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Why FitCalc?
FitCalc started as a simple idea: put the fitness calculators people actually search for in one place, without accounts, paywalls, or apps to download. Every number above uses established, published formulas — Mifflin–St Jeor for calories, the U.S. Navy method for body fat, the Riegel formula for pace prediction, Epley for one-rep max — rather than anything proprietary or unverified.
These tools give estimates for general planning, not medical advice. Individual factors like medical conditions, medication, genetics, and training history can all shift your real numbers away from a formula's prediction. If you're managing a health condition or training for a specific event, it's worth checking your plan with a doctor, registered dietitian, or coach who knows your full picture.
Every calculator was checked against worked examples from its source paper, cross-referenced against at least two established reference tools, and tested at the extremes where unit-conversion bugs usually hide. The metric and imperial modes are also verified against each other. If you want the full detail — which equation sits behind each tool, how accurate it is, and where it stops being reliable — that's all set out on the about and methodology page.
FitCalc is run by one person in the UK and funded by advertising and Amazon affiliate links, both disclosed openly. No brand has paid for a mention anywhere on this site. Found an error or want a calculator that isn't here? Get in touch.
Go deeper
Full guides behind every calculator — the formulas, the science, and how to actually use your numbers.
Calculated using the Mifflin–St Jeor equation, the formula most dietitians consider the most accurate for estimating everyday calorie needs. This is an estimate for general planning, not medical advice. Your TDEE isn't fixed — it shifts as your weight, activity, and age change, so it's worth recalculating every few weeks rather than treating one number as permanent.
How many calories should I eat to lose weight?
Aim for roughly 300–500 calories below your TDEE for gradual, sustainable fat loss — more aggressive deficits tend to be harder to stick to and can cost you muscle mass.
Why does my calorie need change so often?
Body weight, training volume, sleep, and even stress all shift your metabolic rate slightly, which is why it's worth rechecking your number every 4–6 weeks rather than setting it once.
BMI is a broad screening measure and doesn't account for muscle mass, bone density, or body composition — treat it as a starting point, not a diagnosis. It was designed for population-level health studies, not for judging any one person's build — someone carrying a lot of muscle can score "overweight" despite low body fat.
Is BMI accurate for athletes?
Not reliably — muscle weighs more than fat, so muscular or highly trained people are often misclassified. The body fat % calculator gives a more useful picture for that group.
What BMI range is considered healthy?
18.5–24.9 is the standard "normal weight" range used by most health bodies, though it doesn't account for age, sex, or muscle mass.
Tip: run the Calories tab first, then bring your daily target here to see it split into grams of protein, carbs, and fat. There's no single "correct" macro split — the right ratio depends on your goal, training style, and what you can realistically stick to long-term.
Which macro split should I choose?
Balanced suits most general fitness goals, high-protein helps preserve muscle in a calorie deficit, and low-carb can suit those who feel better eating fewer carbohydrates — try one for a few weeks and adjust based on how you feel and perform.
Do I need to hit my macros exactly every day?
No — treat these numbers as a target range rather than a strict rule. Getting within 10–15g most days matters far more than hitting them to the gram.
Uses the U.S. Navy tape-measure method — measure waist at the navel, neck just below the larynx, and (for women) hips at the widest point. Less precise than DEXA or calipers, but no equipment needed. It trades some precision for convenience — it typically lands within a few percentage points of a DEXA scan, which is plenty accurate for tracking change over time.
How often should I remeasure?
Every 4–6 weeks is plenty. Body fat changes slowly, and measuring more often mostly adds noise from water retention and measurement error rather than real signal.
Why do men and women use different measurements?
Fat distribution differs by sex, so the Navy method uses separate formulas — men's is based on waist and neck, women's adds a hip measurement for a more accurate estimate.
Water intake calculator
Daily water target
2.6L
About 11 cups (250ml each)
Baseline of 35ml per kg of body weight, adjusted for exercise and climate. Includes water from food and drinks generally — needs vary by individual and medical conditions. Thirst and urine colour (pale yellow is the target) are simpler day-to-day gauges than any formula — use this number as a starting point, not a strict quota.
Can I drink too much water?
Yes, though it's rare — drinking excessive amounts in a short period can dilute sodium levels dangerously. Spread your intake across the day rather than front-loading it.
Does coffee or tea count toward my total?
Yes, in moderation — caffeinated drinks have a mild diuretic effect, but for most people they still contribute net fluid, so there's no need to only count plain water.
Race pace predictor
Predicted finish times
5K24:10
10K52:00
Half marathon1:55:30
Marathon4:00:15
Uses the Riegel formula, a standard method for predicting endurance performance across distances from one recent result. Assumes similar training and conditions for both races, so predictions get less reliable for very different distances — a fast 5K time will usually overestimate marathon pace.
Why is my marathon prediction so much slower than expected?
Endurance drops off faster than short-distance speed predicts, especially without dedicated long-run training — treat marathon predictions as optimistic rather than guaranteed.
How accurate is this for beginners?
Less accurate than for experienced runners, since pacing strategy and fuelling matter more over longer distances — use it as a rough guide, not a race-day plan.
One-rep max calculator
Estimated bench press 1RM
117kg
85% · 90kg 90% · 105kg 95% · 111kg
Estimated using the Epley formula. Each lift gets its own saved weight/reps, so switching between bench, squat, and deadlift won't overwrite your numbers. Accuracy drops for sets beyond ~12 reps — formula-based 1RMs are estimates, not guarantees, and depend on technique and fatigue as much as the numbers you enter.
Should I actually attempt my calculated 1RM?
Not without experience and a spotter — most lifters use the estimate to plan training percentages (like the 85/90/95% figures above) rather than testing a true max regularly.
Why do my bench, squat, and deadlift numbers look so different?
Different lifts recruit different muscle groups and leverages — deadlift and squat typically allow heavier loads than bench press for most lifters, which is completely normal.
We'll ask your browser for your location — nothing is stored or sent anywhere except Google's search.
Results come from Google Places. Distance shown is straight-line, not driving distance — tap Directions for a real route. A 5km radius suits most cities; widen it to 10km in less densely populated areas, or narrow to 2km if you'd rather walk or cycle there.
Why does it need my location?
Nearby gym search only works by comparing your coordinates against gym locations — without it, there'd be no way to know what's actually near you. Nothing is stored.
What if no gyms show up?
Try a larger radius, or check that location permission wasn't blocked in your browser settings — some browsers only ask once and remember a previous "block."
Ideal weight calculator
Reference ideal weight
70kg
Range across common formulas: 65–75 kg
Uses the Devine formula (1974), originally developed for drug dosing and now the most widely used "ideal weight" equation in clinical practice. The range shown also includes the Robinson, Miller, and Hamwi formulas — they disagree by design, since "ideal weight" was never a single, precisely defined concept. Treat this as a rough reference point, not a target to chase; body composition and frame size matter far more than where you sit on this chart.
Why do the formulas disagree so much?
Each was derived from a different population decades ago, and none account for muscle mass, frame size, or body composition — they're all linear estimates based on height alone, which is a genuine limitation.
Should I try to hit this exact number?
No — treat it as a loose reference range, not a target. A muscular person will exceed every one of these formulas while being perfectly healthy; body fat percentage and how you feel matter more than this number.
Uses the Boer formula (1984), validated against underwater-weighing measurements and one of the more accurate equation-based methods available without special equipment. Lean body mass includes muscle, bone, organs, and water — everything except fat. It's a useful number for setting protein targets and tracking body recomposition, but it's still an estimate; a DEXA scan or bioelectrical impedance device will be more precise for any one individual.
Why does this matter more than my total weight?
Total weight doesn't distinguish muscle from fat, so two people at the same weight can have very different lean body mass. It's a more direct number for setting protein targets or tracking whether a diet is costing you muscle.
How accurate is the Boer formula?
Generally within a few kilograms of measured values for most adults, and validated against underwater weighing — but like any equation-based estimate, it can't see your actual body composition the way a scan can.
Percentage of estimated max heart rate — add resting HR for a more precise Karvonen estimate
Max heart rate is estimated using the Tanaka formula (208 − 0.7 × age), which is better validated across adults than the older "220 − age" rule of thumb. Add your resting heart rate for heart-rate-reserve (Karvonen) zones, which account for your individual fitness level rather than age alone. These are estimates — actual max HR varies by roughly ±10–15 bpm between individuals of the same age, so treat zones as a training guide, not a hard limit.
Why is this different from the "220 minus age" formula?
"220 minus age" is a rough rule of thumb from the 1970s with no strong research behind it. The Tanaka formula (208 − 0.7 × age) was derived from a much larger dataset and is considered more accurate across a wider age range.
What's the difference between the two zone methods?
Percentage-of-max zones use only your estimated max heart rate. Heart-rate-reserve (Karvonen) zones also use your resting heart rate, which accounts for your fitness level — two people with the same max HR but very different resting HR get different, more personalised zones.
Uses MET-based energy expenditure (Compendium of Physical Activities), with walking pace mapped to a typical step cadence for that speed. Distance assumes an average stride length. This doesn't account for incline, terrain, or added load — treat it as a reasonable estimate for flat, level walking rather than a precise figure, and note it's calibrated for walking, not running.
Does this work for running?
Not accurately — running burns considerably more per step than walking, and the MET values here are calibrated for walking cadence specifically. This calculator is intended for walking.
Why does pace matter so much?
Faster walking raises your MET value and also compresses more steps into less time, so a brisk pace burns noticeably more than a leisurely one for the same step count.
This gives a general maintenance-calorie estimate for pregnancy based on population averages — it never suggests a deficit, and weight loss is not recommended during pregnancy under any circumstances without direct medical supervision. It cannot account for multiples, pre-existing conditions, complications, or your individual pregnancy. It is not medical advice. Always follow the guidance of your midwife, obstetrician, or GP over any online calculator.
Estimated daily calories
2,200kcal
Pre-pregnancy maintenance + 0 kcal for 1st trimester (NHS guidance)
This is a maintenance-calorie estimate only — never a target for weight loss, which isn't recommended during pregnancy regardless of pre-pregnancy weight. Trimester additions follow NHS guidance: no extra calories in the first trimester, roughly +340 kcal/day in the second, and roughly +450 kcal/day in the third. Individual needs vary significantly with pre-pregnancy weight, activity, multiples, and any pregnancy complications — always confirm your actual needs with your midwife, obstetrician, or GP.
Should I try to lose weight while pregnant?
No — weight loss is not recommended during pregnancy, even for people who were overweight beforehand, unless specifically advised and supervised by a doctor. This calculator only ever estimates maintenance calories, never a deficit.
Why is there no calorie deficit option here?
Deliberately — a deficit option would not be appropriate for a general pregnancy tool given the risks of under-eating during pregnancy. If you have concerns about weight gain, raise them with your midwife or doctor rather than restricting intake yourself.
Two quick questions, then two or three specific things worth getting — not a generic list.
What's your main goal right now?
How long have you been training?
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