Health & Fitness Calculators
Use body, nutrition, pregnancy and fitness estimates with formulas and limitations explained on each page. This hub groups closely related tools so you can move from a broad question to the calculator that matches the exact job.
Each calculator opens with the working tool first, followed by the formula or method, a worked example, input guidance, common mistakes and related calculators. That keeps the category useful for quick calculations while still giving enough context to verify the result.
Calculator groups in this section
Body & Energy
BMI, BMR, TDEE and calorie planning tools.
- BMI Calculator — Calculate body mass index using metric or US units.
- BMR Calculator — Estimate basal metabolic rate using the Mifflin–St Jeor equation.
- TDEE Calculator — Estimate total daily energy expenditure from BMR and activity level.
- Calorie Calculator — Estimate daily calories for maintenance, loss or gain.
- Calorie Deficit Calculator — Estimate a daily calorie target from maintenance calories and a chosen deficit.
- Macro Calculator — Split a calorie target into protein, carbohydrate and fat grams.
Pregnancy & Cycle
Pregnancy and due-date estimates.
- Due Date Calculator — Estimate pregnancy due date from the first day of the last menstrual period.
- Pregnancy Calculator — Estimate gestational age and due date from the last menstrual period.
Fitness & Wellness
Strength, pace, sleep and sizing estimates.
- One Rep Max Calculator — Estimate one-repetition maximum from weight lifted and repetitions.
- Pace Calculator — Calculate pace and speed from distance and finishing time.
- Sleep Calculator — Find suggested bedtimes using 90-minute sleep cycles.
How to choose the right calculator
Start with the question you are trying to answer, not just the number you already have. A focused calculator usually gives clearer inputs and a more useful result than a general-purpose tool. If your problem changes units, formula type or planning goal, follow the related-calculator links instead of reusing a tool that was built for a different purpose.
Accuracy, assumptions and rounding
Simple mathematical and unit-conversion tools follow fixed relationships. Finance, health, construction, automotive and other planning calculators may also depend on assumptions you supply. Review the method on the individual calculator page, keep units consistent, and treat estimates as planning information rather than professional advice or a guaranteed real-world outcome.
See our calculator methodology for more detail about formulas, browser-based processing, units, rounding and update practices.