Hypothyroid Calorie Calculator
This calculator tells you how many calories to eat per day with hypothyroidism to lose weight, maintain your weight, or protect your metabolism while you get your thyroid dialed in. It’s built for patients with hypothyroidism, Hashimoto’s thyroiditis, subclinical hypothyroidism, or post-thyroidectomy status, and it adjusts for the 5 to 40 percent metabolic slowdown that every generic calorie calculator misses[1][2].
Here’s how to use it:
Enter your age, sex, height, weight, activity level, and thyroid status, flag any modifiers that apply, and pick whether you want to lose weight or maintain. The calculator returns your hypothyroid-adjusted daily calorie target, your protein and carb floors, your realistic monthly weight loss rate, and a comparison against what a generic calorie calculator would tell a person without thyroid disease.
Deficits are capped at 100 to 150 calories per day on purpose. A bigger deficit drops T3, raises reverse T3, and slows thyroid metabolism further, which is the opposite of what you want[5][9].
Note: This calculator is a tool, not a meal plan. Don’t change your thyroid medication or start a calorie deficit based on the results without talking to your doctor first. Skip the deficit entirely if you’re pregnant, breastfeeding, or being treated for an eating disorder.
Hypothyroid Calorie Calculator
Calculate your daily calorie target factoring in your thyroid status, designed to help you lose weight without crashing your metabolism.
The Standard Calculator Lie
Your Total Weight Loss Potential
Your Macro Floors
Protein minimum
Daily, regardless of weight or goal. Critical for preserving muscle.
Carbs minimum
Default for non-insulin-resistant users. Supports T3 conversion.
Hit these two floors, then fill the rest of your calories with whatever combination of protein, carbs, or healthy fats works best for you. As long as protein and carbs hit the floor, the rest of your distribution is up to you.
Why Your Deficit Is Smaller Than Other Calculators
Next Steps to Boost Your Results
The diet deficit is just one of three levers. The biggest gains come from also optimizing your thyroid function. Use these tools to fix the root cause:
Written and medically reviewed by Dr. Westin Childs, D.O. Last reviewed: April 22, 2026.
How to Use This Calculator
Step #1: Enter Your Sex, Age, Height, and Weight
These four inputs tell the calculator the baseline for how many calories your body burns just existing[3].
Men burn about 5% more than women at the same weight. Your metabolism also drops a little each decade after age 20. Height and weight do the rest of the work.
Use the toggles next to each field if you prefer centimeters or kilograms. Either works.
One thing to know: if your BMI is 30 or higher (which is common with hypothyroidism), the calculator adjusts the math in the background so your number doesn’t come back artificially high[4]. You don’t have to do anything for that to happen. Just enter your real weight.
Step #2: Pick Your Activity Level
Your activity level tells the calculator how many calories you burn through daily movement on top of your baseline metabolism. The choices are sedentary (desk job, little or no exercise), lightly active (a few walks or light workouts per week), moderately active (structured exercise most days), very active (hard training most days), and athlete (twice-daily training or hard physical labor).
Most thyroid patients overestimate this. If you sit at a desk and walk a few times a week, you’re sedentary or lightly active, not moderate. Moderate is real structured exercise most days. When in doubt, pick the level below where you think you fit. Hypothyroid fatigue makes everything feel harder, which makes you overestimate. Pick too high and the calculator hands you more calories than you’re actually burning.
Step #3: Pick Your Thyroid Status
Your thyroid status is what makes this calculator different from every generic calorie calculator. Generic calculators assume your thyroid is working normally and burns calories at a normal rate. This one adjusts your calorie target for the 5 to 40 percent metabolic slowdown caused by hypothyroidism, subclinical hypothyroidism, Hashimoto’s thyroiditis, or thyroidectomy.
Pick the option that matches your situation: newly diagnosed and untreated, subclinical, T4-only with or without ongoing symptoms, T4+T3 combination or NDT with or without ongoing symptoms, or post-thyroidectomy. Each option adjusts your metabolism differently in the background. Post-thyroidectomy gets the biggest cut because removing the thyroid permanently damages T4-to-T3 conversion[8].
Not sure which option fits? Let your symptoms be the tie-breaker. Still tired, cold, and struggling to lose weight? Pick “ongoing symptoms,” even if your TSH is in range. Feeling great? Pick “optimal labs.”
Step #4: Pick Your Goal and Deficit Pace
Your goal tells the calculator whether to return maintenance calories or a deficit. Pick “Lose Weight” and you’ll also choose a deficit pace: Slow and Steady (100 calories per day below maintenance, recommended for hypothyroid patients) or Moderate (150 calories per day). Pick “Maintain Weight” and the calculator returns the number of calories to eat to stay where you are.
100 to 150 calories sounds small. On purpose. Most calorie calculators recommend a 500 calorie deficit, which is the number that crashes thyroid patients. A big deficit tells your body there’s a famine and your metabolism slows even more[5][6]. Slow and steady is the only pace that works long-term for thyroid patients.
Step #5: Flag Any Modifiers That Apply
The modifier checkboxes adjust your calorie and carbohydrate targets for four conditions that make hypothyroid weight loss harder: menopause or perimenopause, a history of crash dieting or eating disorders, a current weight loss plateau, and insulin resistance or PCOS. Flag any that apply; they’re optional but worth using if they fit your situation.
Check menopause or perimenopause if it applies; your metabolism is taking another hit on top of the thyroid. Check the crash-dieting flag if you’ve yo-yo’d or had an eating disorder; years of severe restriction leave a permanent dent[6]. Check the plateau flag if you’ve been stuck doing everything right. Check insulin resistance or PCOS if it applies; this one drops your carb floor from 100g to 50g.
Understanding Your Results
Your Daily Calorie Target
Your daily calorie target is the large number displayed at the top of your results. It’s the number of calories you should eat per day to hit your chosen goal (weight loss or maintenance), adjusted for your hypothyroid metabolism, activity level, and any modifiers you flagged.
One catch: if your target falls below the safe minimum (1,200 for women, 1,500 for men), the calculator overrides the deficit and hands you maintenance instead. You’ll see a note telling you to skip calorie cutting and fix your thyroid first. This usually shows up in post-thyroidectomy patients with desk jobs. For that group, calorie restriction isn’t the answer. Getting the thyroid medication dialed in is.
The Three-Tier Comparison
The three-tier comparison shows three side-by-side numbers underneath your target: what a generic calorie calculator would recommend for you, what your body actually burns with your thyroid factored in, and your safe minimum calorie floor below which you shouldn’t drop.
Look at the gap between the first two numbers. That gap is why every diet you’ve tried has failed. If a generic calculator told you to eat 1,800 calories to lose weight but your real maintenance is 1,500, you were in a surplus, not a deficit. You were set up to fail before you took a single bite.
Your Total Weight Loss Potential
Your total weight loss potential with hypothyroidism comes from three smaller levers stacked together, not from a single giant calorie deficit: a small daily deficit of 100 to 150 calories, the metabolic burn you recover when your thyroid medication is optimized, and strength training paired with at least 100 grams of protein per day. Stacked together, these three levers typically produce 2 to 3 pounds of real fat loss per month.
Lever one is the 100 to 150 calorie deficit from this calculator. Lever two is the metabolism you get back when your thyroid medication is actually optimized (the biggest one for most people, and nobody talks about it). Lever three is strength training plus 100g of protein per day, which raises your resting burn by about 50 calories per day over 6 to 12 months[10]. Stack all three and you’re in an effective deficit of 250 to 350 calories per day, which is 2 to 3 pounds of real fat loss per month.
Slower than the 1 to 2 pounds per week every influencer promises. But it’s sustainable, your muscle stays, your metabolism doesn’t crash, and the weight stays off.
Your Macro Floors
Your macro floors are the two daily minimums you need to hit with hypothyroidism: at least 100 grams of protein per day, and either 50 or 100 grams of carbohydrates per day depending on whether you flagged insulin resistance. Hit those two numbers first; then fill the rest of your calorie target with whatever mix of protein, carbs, or fats works for your life.
Protein is non-negotiable. Miss your protein in a deficit and you lose muscle instead of fat, which wrecks your metabolism on top of an already suppressed thyroid. Protein also gives your body the raw materials it needs to make thyroid hormone[11].
Carbs trip most thyroid patients up. Too low (under 50g per day) and you suppress T3 within a few weeks[9]. Too high and you’ll struggle with blood sugar if you have insulin resistance or PCOS. The calculator gives you the right carb floor for your situation.
Why Your Deficit Looks So Small
The 100 to 150 calorie deficit this calculator recommends is deliberately small because larger deficits actively sabotage weight loss in hypothyroid patients. A 500 calorie deficit (the standard weight loss recommendation) drops T3, raises reverse T3, suppresses leptin, and slows metabolism further, which is exactly what someone with an already-suppressed thyroid can’t afford[5][9].
The 500-calorie deficit you’ve read about a thousand times isn’t a deficit for thyroid patients. It’s starvation. Your metabolism is already running 15 to 20% below normal. Cutting 500 more tells your body there’s a famine; T3 drops, reverse T3 climbs, leptin falls, and your metabolism slows down even more[5].
The Biggest Loser contestants were still burning 500+ calories per day below normal six years after the show ended[6]. Six years of damage from one season of aggressive cutting, and they didn’t even start with a thyroid problem. A 100 to 150 calorie deficit flies under that starvation radar, so the damage doesn’t happen.
Thyroid Status Metabolism Adjustment Reference Table
The table below shows the metabolism adjustments the calculator applies for each thyroid status, ranging from 0 percent for patients on T4+T3 combination therapy with optimal labs to 18 percent for post-thyroidectomy patients. The optimization column is how much of that calorie burn you can get back by getting your thyroid dialed in.
| Thyroid Status | Metabolism Adjustment | Optimization Potential | Source |
|---|---|---|---|
| Newly diagnosed or untreated hypothyroidism | -15% | +12% | Untreated metabolic suppression[1][2] |
| Untreated subclinical hypothyroidism | -5% | +5% | Subclinical metabolic effects[12] |
| T4-only therapy with ongoing symptoms | -10% | +7% | Suboptimal T3 on T4 alone[7] |
| T4-only therapy at optimal labs | -3% | +3% | Residual low T3 despite normal TSH[7] |
| T4+T3 combo or NDT with ongoing symptoms | -7% | +7% | Dose or ratio needs adjustment[13] |
| T4+T3 combo or NDT at optimal labs | 0% | 0% | Closest to a healthy thyroid[13] |
| Post-thyroidectomy (full or partial) | -18% | +13% | Permanent conversion loss[8] |
The optimization column is what feeds the “thyroid optimization” line in your results. It’s the daily calorie burn you can realistically get back by moving from where you are today to where you could be.
Example: a newly diagnosed patient who gets on the right medication and hits optimal labs can get back about 12% of their suppressed metabolism. For an average patient that’s around 200 calories per day.
That’s 200 calories per day of weight loss leverage you didn’t have before. Every day. Forever.
Not sure if your thyroid medication is working? Use the Optimal Thyroid Lab Test Calculator to check.
Think your TSH is telling you the dose needs to change? Use the Levothyroxine Dose Adjustment Calculator.
Thinking about switching from T4-only to combo therapy or NDT? Use the Thyroid Medication Conversion Calculator.
Frequently Asked Questions
Most hypothyroid women should eat between 1,200 and 1,600 calories per day to lose weight, and between 1,400 and 1,900 calories per day to maintain their weight. Most hypothyroid men should eat between 1,500 and 2,000 calories per day to lose weight, and between 1,800 and 2,400 to maintain. These ranges are 10 to 40 percent below what a generic calorie calculator would recommend for a person of the same age, height, and weight without thyroid disease.
Your exact number depends on your age, height, weight, activity level, and how suppressed your metabolism is from your thyroid condition. The calculator at the top of this page gives you the exact number.
Whatever number you get, the deficit should be small (100 to 150 calories below maintenance). Not 500. A 500-calorie deficit crashes your thyroid further. A 100 to 150 deficit lets you lose weight without breaking your metabolism in the process.
If you can’t lose weight with hypothyroidism even though you’re in a calorie deficit, it’s almost always because you’re not actually in a deficit. Hypothyroidism slows metabolism by 10 to 40 percent compared to someone without thyroid disease, so the “deficit” a generic calorie calculator gives you is often just maintenance calories (or even a surplus) for a hypothyroid body[1][2].
Here’s what I mean: every generic calorie calculator assumes your metabolism is normal. If your thyroid is slowing your metabolism by 15%, then what the app says is a 500-calorie deficit is actually closer to maintenance. You think you’re cutting. You’re not.
That’s why “doing everything right” doesn’t move the scale.
The other big reason is what all your past diets did to you. If you’ve spent years crash dieting, doing very low calorie plans, or yo-yo’ing up and down, your metabolism is running anywhere from 200 to 500 calories below where it should be. And that damage can stick around for years after the last diet ended[6].
The calculator factors both of these in. The number it gives you is realistic for your actual metabolism, not the one the formula assumes you have.
Hypothyroidism slows metabolism anywhere from 5 to 40 percent depending on severity, treatment status, and whether the thyroid gland is still intact[1][2]. Untreated hypothyroidism causes the biggest drop at 15 to 40 percent below normal. Subclinical hypothyroidism is milder at 3 to 7 percent below normal[12]. Patients on T4-only medication with ongoing symptoms run 5 to 10 percent below normal[7]. Post-thyroidectomy patients run 15 to 20 percent below normal even on the right dose[8].
Untreated hypothyroidism is the worst; thyroid hormone runs every cell in your body, so when T3 falls, your entire calorie burn falls with it. Post-thyroidectomy is the hardest to reverse because removing the gland permanently hurts your body’s ability to convert T4 into T3. Patients on T4+T3 combination or NDT with optimal labs are the closest to normal.
Yes, hypothyroid patients should eat in a calorie deficit to lose weight, but the deficit should only be 100 to 150 calories below maintenance per day, not the standard 500-calorie deficit recommended for healthy adults. A larger deficit triggers further metabolic slowdown, drops T3 levels, raises reverse T3, and makes weight loss harder instead of easier[5][6][9].
The calculator also has a safety floor at 1,200 calories for women and 1,500 for men. If your target hits the floor, the calculator tells you to skip the deficit entirely and fix your thyroid first. You can’t diet your way out of a crashed metabolism. You have to fix the thyroid, build the muscle, and earn your maintenance calories back first.
Hypothyroid patients should eat at least 100 grams of protein per day as a minimum floor, regardless of body weight or weight loss goal. Patients who are strength training or trying to recomp (lose fat and gain muscle at the same time) should eat 0.8 to 1.0 grams of protein per pound of goal body weight, which usually works out to 120 to 160 grams per day[11].
Three reasons: protein protects muscle in a deficit (lose muscle and you lose metabolism), protein keeps you full, and protein gives your body the raw materials it needs to make thyroid hormone[11].
For more, read my full guide on protein needs for thyroid patients.
Most hypothyroid patients can realistically lose half a pound to 1.5 pounds of fat per month from diet alone, and 2 to 3 pounds per month when they combine a small calorie deficit with thyroid optimization, strength training, and at least 100 grams of protein per day. That works out to 25 to 40 pounds of fat loss over the course of a year when all three levers are pulled together.
Diet alone gets you half a pound to 1.5 pounds per month. Slower than the influencer before-and-afters, but it’s the rate that doesn’t crash your metabolism and the rate at which the weight actually stays off.
Speed it up by stacking all three levers: the small deficit, thyroid optimization, and strength training plus 100g of protein. Patients who try diet alone almost always hit a plateau by month 3.
Post-thyroidectomy weight loss is harder than other forms of hypothyroidism because removing the thyroid gland eliminates the body’s ability to fine-tune hormone output in real time. Even with an in-range TSH and a “perfect” dose, post-thyroidectomy patients run about 15 to 20 percent below normal metabolism, the biggest drop of any thyroid patient group[8]. Most patients feel dramatically better when T3 (liothyronine or Cytomel) is added to their T4 medication, when they switch to NDT, or when their T4 dose gets pushed into the upper end of the optimal range.
A healthy thyroid constantly adjusts hormone output moment to moment. Take the thyroid out and you’re stuck on a fixed dose whether your body needs more that day or less. The good news is most post-thyroidectomy patients feel dramatically better when T3 gets added, when they switch to NDT, or when their T4 dose gets pushed to the upper end of the optimal range.
For more, read my guide on weight gain after thyroidectomy.
Levothyroxine helps with weight loss only if it’s actually normalizing your thyroid function at the cellular level, which means bringing free T3 into the optimal range (not just lowering TSH). About 15 to 20 percent of hypothyroid patients don’t convert T4 into T3 well enough on levothyroxine alone, and those patients stay 5 to 10 percent below normal metabolism with ongoing weight, fatigue, and hair loss symptoms even when their TSH looks “in range”[7][13]. Adding T3 (liothyronine or Cytomel) or switching to natural desiccated thyroid usually fixes that.
Your doctor puts you on a dose that brings your TSH into range and the labs look fine, but your free T3 stays low. Your metabolism runs 5 to 10 percent below normal, you still feel tired, and the weight won’t come off[7]. The problem isn’t that you’re not trying hard enough. The medication isn’t working for your body.
Not sure if your dose is working? Use the Optimal Thyroid Lab Test Calculator. Think your dose needs to change? Use the Levothyroxine Dose Adjustment Calculator.
To break a hypothyroid weight loss plateau, take a 1 to 2 week diet break at maintenance calories, then re-check a full thyroid panel (TSH, free T4, free T3, reverse T3) before cutting calories again. If the labs are off, your dose likely needs to be adjusted or you need T3 added. If the labs look good, add strength training and push protein to 120 to 150 grams per day to build muscle and restart fat loss.
The diet break sounds backwards, but a plateau is almost always your body’s response to a long deficit. T3 has dropped, leptin has fallen, and your metabolism has quietly slowed down to match what you’ve been eating. Eating at maintenance for 1 to 2 weeks lets things reset, and a small deficit afterwards usually restarts weight loss within a couple weeks.
A lot of “diet plateaus” in thyroid patients are actually thyroid plateaus. Get a full panel (TSH, free T4, free T3, reverse T3) and run it through the Optimal Thyroid Lab Test Calculator to see if your labs explain the stall.
To calculate TDEE (Total Daily Energy Expenditure) with hypothyroidism, start with the standard Mifflin-St Jeor equation to get your baseline BMR, multiply by your activity factor to get the non-thyroid TDEE, then reduce the result by 5 to 40 percent based on your thyroid status (untreated, subclinical, on T4-only with symptoms, post-thyroidectomy, etc.). The calculator at the top of this page does all of that automatically, including the thyroid-specific adjustments that generic TDEE calculators miss.
TDEE (Total Daily Energy Expenditure) is the total calories your body burns in 24 hours. A generic calculator runs height, weight, age, and activity and assumes your metabolism is at 100%. For a thyroid patient, your real TDEE is 5 to 40 percent below what a generic calculator spits out, and that gap is what’s been sabotaging your weight loss. Use the calculator at the top of this page and it does all of that for you.
References
- Jonklaas J, Bianco AC, Bauer AJ, et al. Guidelines for the treatment of hypothyroidism: prepared by the American Thyroid Association task force on thyroid hormone replacement. Thyroid. 2014;24(12):1670-1751. View on PubMed
- Iwen KA, Schroder E, Brabant G. Thyroid hormones and the metabolic syndrome. European Thyroid Journal. 2013;2(2):83-92. View on PubMed
- Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition. 1990;51(2):241-247. View on PubMed
- Frankenfield D, Roth-Yousey L, Compher C. Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. Journal of the American Dietetic Association. 2005;105(5):775-789. View on PubMed
- Rosenbaum M, Leibel RL. Adaptive thermogenesis in humans. International Journal of Obesity. 2010;34(Suppl 1):S47-S55. View on PubMed
- Fothergill E, Guo J, Howard L, et al. Persistent metabolic adaptation 6 years after “The Biggest Loser” competition. Obesity (Silver Spring). 2016;24(8):1612-1619. View on PubMed
- Wiersinga WM, Duntas L, Fadeyev V, Nygaard B, Vanderpump MP. 2012 ETA guidelines: the use of L-T4 + L-T3 in the treatment of hypothyroidism. European Thyroid Journal. 2012;1(2):55-71. View on PubMed
- Hoang TD, Olsen CH, Mai VQ, Clyde PW, Shakir MK. Desiccated thyroid extract compared with levothyroxine in the treatment of hypothyroidism: a randomized, double-blind, crossover study. Journal of Clinical Endocrinology and Metabolism. 2013;98(5):1982-1990. View on PubMed
- Spaulding SW, Chopra IJ, Sherwin RS, Lyall SS. Effect of caloric restriction and dietary composition on serum T3 and reverse T3 in man. Journal of Clinical Endocrinology and Metabolism. 1976;42(1):197-200. View on PubMed
- Westcott WL. Resistance training is medicine: effects of strength training on health. Current Sports Medicine Reports. 2012;11(4):209-216. View on PubMed
- Pasiakos SM, Cao JJ, Margolis LM, et al. Effects of high-protein diets on fat-free mass and muscle protein synthesis following weight loss: a randomized controlled trial. FASEB Journal. 2013;27(9):3837-3847. View on PubMed
- Karmisholt J, Andersen S, Laurberg P. Variation in thyroid function tests in patients with stable untreated subclinical hypothyroidism. Thyroid. 2008;18(3):303-308. View on PubMed
- Wiersinga WM. Therapy of endocrine disease: T4 + T3 combination therapy: is there a true effect? European Journal of Endocrinology. 2017;177(6):R287-R296. View on PubMed