Free thyroid tools
Thyroid tools and calculators
Free tools built by a thyroid doctor to help you understand your labs, track your progress, and take control of your thyroid health.
Each tool below was designed based on years of clinical experience treating thyroid patients and reflects the optimal ranges and ratios used in functional and integrative medicine, not just the standard reference ranges.
Start here
Three tools to try first
If you don’t know which one you need, start with one of these three.
Optimal Thyroid Lab Test Calculator
Enter your labs and see which ones are optimal, not just normal.
Open this tool →Thyroid Medication Conversion Calculator
Switching medications? Get your equivalent dose in seconds.
Open this tool →Thyroid Supplement Quiz
Answer 6 questions and get a supplement stack matched to your condition.
Open this tool →Lab analysis
Make sense of your lab results
Optimal Thyroid Lab Test Calculator
Enter your thyroid lab values and instantly see whether your results fall within the optimal range, not just the standard reference range. Covers all seven key thyroid markers: TSH, free T3, free T4, total T3, reverse T3, TPO antibodies, and thyroglobulin antibodies.
Reverse T3 Ratio Calculator
Your reverse T3 level alone doesn’t tell the full story. What matters is the ratio between your free T3 and reverse T3. This calculator computes your reverse T3 ratio and tells you whether it falls within the optimal range used in functional medicine.
Thyroid Lab Unit Converter
Your lab report says 17.2 and the range online says 1.4 to 1.77, and nothing is wrong with either number: US labs and international labs use different units. Pick your lab, type your number in either box, and the other unit fills in as you type, with the optimal range shown both ways.
T4 to T3 Conversion Calculator
T4 is a storage hormone, and it does almost nothing until your body converts it into active T3. This interactive calculator turns your free T3, free T4, and reverse T3 into a 0 to 100 conversion score, with a live diagram that shows how much hormone is reaching your cells and how much is going to the reverse T3 dead end.
Medication and dosing
Get your dose right
Thyroid Medication Conversion Calculator
Switching thyroid medications or wondering what an equivalent dose would be? Enter your current medication (or combination of medications), pick the one you want to switch to, and instantly see your equivalent dose. Toggle between Dr. Childs’ recommended conversions and conventional conversion metrics.
Levothyroxine Dosage Calculator
Get a weight-based starting dose of levothyroxine for hypothyroidism, Hashimoto’s, subclinical hypothyroidism, or post-thyroidectomy. The calculator adjusts automatically for pregnancy, age, heart conditions, and weight using the 1.6 mcg/kg/day full-replacement formula from ATA and AACE guidelines.
Levothyroxine Dose Adjustment Calculator
Already on levothyroxine and wondering if your dose needs to change? Enter your most recent TSH, your current dose, and your clinical scenario, and this calculator tells you whether to go up, stay the same, or come down. It uses ATA/AACE step-wise adjustment rules with pregnancy-specific and cancer-specific TSH targets built in.
Armour Thyroid & NDT Dosage Calculator
Get a weight-based starting dose of Armour Thyroid, NP Thyroid, or compounded NDT using Dr. Childs’ clinical conversion math, which values T3 at 3x T4 potency and gives you more NDT than the conventional pharmaceutical chart. The calculator returns your dose in grains and milligrams, breaks down the T4 and T3 components, and builds a 4-week titration schedule so the T3 doesn’t hit you all at once.
Pregnancy TSH Calculator
Pregnant or planning to be and on thyroid medication? This calculator checks whether your TSH is optimal for your trimester and provides levothyroxine dose adjustments if it isn’t. It uses the 2017 ATA Pregnancy Guidelines as the baseline and lets you compare three TSH targets: Dr. Childs’ Optimal range, a Functional range, and the ATA Standard range.
Missed Thyroid Dose Calculator
Missed a dose of Synthroid, levothyroxine, Cytomel, or Armour Thyroid and wondering how much it matters? This calculator uses T4’s 7-day half-life to estimate how far your serum levels have dropped based on the number of days missed, your medication type, and your daily dose. It also flags pregnancy and thyroid cancer cases that need faster follow-up.
T4 to T3 Ratio Calculator
On T4-only medication and still symptomatic? This calculator tells you how much T3 to add to your current T4 dose to hit a physiological 5:1 T4-to-T3 ratio, matching the 80/20 output of a healthy thyroid gland. Built for patients on T4 monotherapy with poor conversion, Hashimoto’s, or post-thyroidectomy who do better on combination therapy.
Thyroid Medication Timing Optimizer
Taking your thyroid medication next to the wrong supplement can cost you a chunk of your dose without you ever knowing it happened. Enter your thyroid medication, everything else you swallow, and the times you take them now. It sorts out what has to move, what can stay exactly where it is, and why, covering iron, calcium, coffee, acid blockers, binders, antibiotics and more than 2,000 medication and supplement names.
Thyroid Medication Interaction Checker
Does creatine interact with levothyroxine? Does berberine? Does the prednisone you were put on last year? Most interaction checkers only look at absorption, which is the smallest part of this. Enter your thyroid medication and everything else you take, and this sorts your list by what each one is actually doing to your thyroid.
TSH Suppression Calculator
A suppressed TSH protects some people and quietly costs others, and the trade is supposed to be re-negotiated as your situation changes. This calculator weighs your benefit side (mainly thyroid cancer protection, by risk tier and response) against your risk side (heart rhythm with age, bone loss after menopause).
Cytomel & Liothyronine Dosage Calculator
Levothyroxine dosing has charts everywhere. T3 dosing has almost nothing, and the math is different: T3 is roughly 3 times as potent, and adding it means your levothyroxine usually comes down at the same time. This calculator turns your current dose into real T3 numbers.
TSH Dose Calculator
Pick the TSH you’re aiming for, the optimal band of 0.5 to 1.0 or the standard target, and find out whether your current levothyroxine dose can get you there, in the same 12.5 to 25 mcg steps doctors actually use.
Cancer and nodules
Nodules, biopsies, and cancer surveillance
TI-RADS Thyroid Nodule Calculator
Score your thyroid nodule using both the ACR TI-RADS system (TR1 through TR5) and the ATA Sonographic Pattern system side by side. Enter your ultrasound features and nodule size and get your risk category, malignancy estimate, and biopsy size threshold from both major classification systems at once.
Bethesda Thyroid Biopsy Calculator
Got your thyroid biopsy results back? Enter your Bethesda category (1 through 6) to see your cancer risk percentage from both the 2017 and 2023 versions of the Bethesda System, whether molecular testing (Afirma, ThyroSeq, ThyGenX) is appropriate, and whether you need surgery or surveillance. Optional modifiers for TI-RADS score, family history, and radiation history refine the recommendation further.
Thyroid Nodule Growth Calculator
Had two ultrasounds on the same nodule? Enter the three dimensions and dates from each scan and this calculator computes your volume change, per-dimension growth, annual growth rate, and a clear yes-or-no answer on whether your nodule meets the ATA significant growth criteria that warrant repeat biopsy or re-evaluation. Optional Bethesda category and TI-RADS score refine the next-step recommendation.
Thyroid Cancer Staging Calculator
Had a thyroidectomy for thyroid cancer and trying to make sense of your pathology report? Enter your cancer subtype (differentiated, medullary, or anaplastic), your age, and your TNM classification (tumor size, lymph node status, distant spread) and this calculator translates it into your AJCC 8th Edition stage with your 5-year survival rate from SEER population data, the standard treatment approach, and what you can do to support your thyroid through treatment and recovery.
Calcitonin & CEA Doubling Time Calculator
If you have medullary thyroid cancer, how fast your calcitonin and CEA are rising matters more than any single number. Enter 2 or more results with their dates and this calculator works out your doubling time, which is the strongest predictor of recurrence in the guidelines. It handles both markers separately so you can see whether they agree.
Thyroid Cancer Recurrence Risk Calculator
After thyroid cancer surgery, your follow-up plan comes from your ATA recurrence risk tier: low, intermediate, or high. This calculator reads the same pathology report details your endocrinologist uses (extension, lymph nodes, vascular invasion, margins) and places you in your tier, with the reminder that matters most: recurrence risk is not survival.
Response To Therapy Calculator (Dynamic Risk)
Your initial risk tier was set once, on the day you were staged. What matters more is how you actually responded to treatment, which is what your care team re-assesses at every visit using your thyroglobulin, your antibodies, and your imaging. This calculator gives you the same four-category read, including the adapted cutoffs for lobectomy and no-RAI patients.
Weight and metabolism
Eat for a slower metabolism
Thyroid Weight Gain Calculator
How much of your extra weight is actually your thyroid? In my experience the answer is 10 to 20 pounds at most, split between true fat and fluid, and the rest comes from somewhere else. Answer questions about your diagnosis, your medication, and your signals for leptin resistance, insulin resistance, cortisol, estrogen, and daily habits, and this calculator splits your extra weight into its causes, in pounds.
Hypothyroid Calorie Calculator
Standard calorie calculators don’t account for the metabolic suppression caused by hypothyroidism, which can reduce your BMR by 5% to 40%. This calculator uses the Mifflin-St Jeor equation with a thyroid-specific adjustment layer and factors in menopause, insulin resistance, plateau status, and a history of crash dieting.
Hypothyroid Macro Calculator
Find out how much protein, carbs, and fat to eat per day with hypothyroidism. Protein is anchored to grams, not a percentage of calories, so it doesn’t undershoot when you’re in a deficit. Choose from five macro patterns (Thyroid-Optimized, Balanced, Higher Protein, Lower Carb, and Mediterranean) with a sixth Keto option if you flag insulin resistance or PCOS.
Thyroid BMI Calculator
BMI is a simple ratio of weight to height, and it knows nothing about your thyroid: not the fluid a slow thyroid holds, not the muscle it costs you. This calculator gives you your BMI and the healthy weight range for your height, then reads the result differently depending on your diagnosis.
Thyroid BMR & TDEE Calculator
Standard metabolism calculators assume your thyroid works. Yours might not, and an under-treated thyroid lowers what you burn at rest, which is exactly why the standard numbers never work for thyroid patients. This calculator gives you the honest version.
Thyroid Food Checker
Someone handed you a list of foods to avoid, and most of it is wrong for you specifically. This checker asks three questions first (your thyroid situation, your medication, your iodine), then gives you the real answer for broccoli, soy, gluten, dairy, kelp, coffee, and the rest, with the evidence graded honestly.
Iodine Intake Calculator
Iodine hides in dairy, eggs, some bread, and seaweed, and it’s missing from sea salt, restaurant food, and nearly all fruits and vegetables. Look up any food (yes, bananas are in there), then add your real day and see where you land between the 150 mcg target and the 1,100 mcg upper limit.
Supplements
Find your supplement formula
Thyroid Supplement Quiz
Not sure which thyroid supplements are right for you? Answer 6 quick questions about your thyroid type, symptoms, goals, current medication, and recent labs, and this quiz matches you with a personalized 3-supplement stack built for your specific situation. It accounts for diagnosis-specific contraindications so you don’t end up taking the wrong thing for your condition.
Do I Need T2? (Quiz)
T2 is the only over-the-counter thyroid hormone, but most patients have never heard of it. This 6-question quiz walks through your thyroid type, current medication, persistent symptoms, and metabolic status to determine whether direct T2 supplementation is a fit for your situation. No lab values needed.
Hashimoto’s Supplement Quiz
Two people can both have Hashimoto’s and need completely different supplements. This quiz asks about your symptoms, your #1 goal, your thyroid medication, and your TPO antibody level, which is the question most Hashimoto’s quizzes skip. A TPO of 60 and a TPO of 900 are not the same problem.
Hypothyroidism Supplement Quiz
Your thyroid medication matters more than your diagnosis when it comes to which supplements will actually help. This quiz asks what you’re taking and how you feel on your current dose, then builds your picks around that. Being on T4 only and still symptomatic is a different problem from feeling good and wanting to optimize.
Hyperthyroidism Supplement Quiz
An overactive thyroid flips the supplement playbook: everything that supports hormone production is suddenly wrong for you. This quiz screens all of that out, then picks support for what hyperthyroidism actually drains: your minerals, your stress response, your muscle, and your sleep.
Graves’ Disease Supplement Quiz
Graves’ has one cause: antibodies forcing your thyroid to overproduce. That’s why your first pick is always aimed at the immune attack itself, and your other two come from what Graves’ is doing to your body right now, from your eyes to your sleep to your muscle.
Post-Thyroidectomy Supplement Quiz
A thyroid gland makes T4, T3, T2, and T1, and adjusts the mix all day. Surgery took that out, and you likely got handed back one fixed dose of T4. This quiz targets the gap: what was removed, why, what you take now, and how you actually feel on it.
Thyroid Nodule Supplement Quiz
Half of everyone has a thyroid nodule by 60, and the right move depends on three things: how big it is, what the biopsy said, and what your thyroid function is doing. This quiz asks exactly that, and if your biopsy came back suspicious, it sends you to your doctor instead of a supplement bottle.
Quizzes
Find out what you’re dealing with
Thyroid Temperature Test
Your morning temperature is a free, at-home window into your T3 status: your thyroid sets your body’s heat production, so mornings that keep coming in low mean something. Enter one reading, taken before you get out of bed, and this test places it across four bands with corrections for underarm readings and where you are in your cycle.
Hypothyroid Symptom Quiz
Not sure if your symptoms point to a thyroid problem? This weighted screening quiz covers symptoms organized by body system, from metabolic and digestive to skin, hair, cardiovascular, and reproductive. It also factors in risk modifiers like age, sex, and family history. Scoring is built on the specificity principles from the Zulewski clinical score and the Colorado Thyroid Disease Prevalence Study.
Hashimoto’s Symptom Quiz
Wondering if your thyroid symptoms are autoimmune? This quiz weights symptoms by how specifically they point to Hashimoto’s, not just low thyroid function, and factors in autoimmune-specific risk factors like family history, other autoimmune conditions, postpartum status, and prior antibody results. If you’ve already tested positive for thyroid antibodies, the quiz adjusts your tier accordingly.
Hyperthyroid Symptom Quiz
Experiencing a racing heart, unexplained weight loss, or anxiety that won’t quit? This weighted screening quiz combines your symptoms with lab signals and risk factors to distinguish overt hyperthyroidism, subclinical hyperthyroidism, and thyroid hormone over-replacement. It’s organized by body system and flags the patterns most specific to an overactive thyroid or excess thyroid medication.
Graves’ Disease Symptom Quiz
Wondering if your overactive thyroid is Graves’ disease? This quiz combines hyperthyroid symptoms with Graves’-specific tells like eye signs, autoimmune family history, and antibody status to distinguish Graves’ from other causes of hyperthyroidism. It’s designed for adults trying to figure out whether antibody testing or specialist referral is the right next step.
Can I Stop Taking Levothyroxine? (Quiz)
Wondering if you can safely come off levothyroxine, Synthroid, NDT, or any thyroid medication? This 10-question quiz uses research-backed predictors to estimate your odds of discontinuing thyroid medication successfully. It walks through your diagnosis, cause, current labs and dose, and any past attempts to stop.
Thyroid Aging Quiz
Is your thyroid making you look older than you are? This 10-question assessment walks through what you’re seeing in the mirror, from hair thinning and new wrinkles to brittle nails and facial puffiness, and scores how much thyroid-driven aging damage is showing up across your hair, skin, and nails. It then matches you with the specific products that target your damage pattern.
Thyroid Score Test
How optimized is your thyroid, in one number? Rate your 12 symptoms, add your medication, and layer in labs, temperature, and weight if you have them. The exact formula is public: labs 40%, symptoms 30%, weight, temperature, and medication the rest, rebalanced around whatever you enter.
Thyroid vs Adrenal Quiz
Fatigue, weight gain, and brain fog belong to both problems, which is why thyroid patients get told it’s stress and stressed patients chase their thyroid for years. Ten either-or questions that target where the two patterns actually differ: the timing of your crashes, your cravings, your recovery, your sleep.
Thyroid Tracker (Free Account)
Six trackers in one place: your symptoms, weight, medications, supplements, labs, and morning temperatures, feeding one Thyroid Score you can actually watch change. Plus an interference checker for your medication list, a printable summary for your doctor, and a download of all your data.
Find help
Find a doctor who gets it
Find a Thyroid Doctor
Most directories list every doctor with a license. This one only lists doctors and practitioners who pass vetting: full thyroid panels with free T3 and reverse T3, treatment to optimal ranges, and openness to NDT and T3 when they make sense. No one can pay to be on it.
These tools are for informational and educational purposes only and are not a substitute for professional medical advice, diagnosis, or treatment. Always consult with a qualified healthcare provider regarding your thyroid health.
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