Free fitness calculators
Free calculators, with the working shown.
Calculators for energy, macros, protein, strength and body fat, and for the business side of coaching. Each one uses a published method, shows its formulas and lists its sources, so you can check the numbers yourself or explain them to a client.
- Free, no sign-up
- Metric or imperial
- Runs in your browser
What are these calculators for?
They answer the numbers questions coaches and their clients ask most: how many calories to eat, how much protein, how to split macros, how strong you are and how lean. Coaches also get two business tools, for take-home income and for how many clients they can coach well. All of them are free.
- Published equations, with the formulas on every page
- Sources linked, from journals and official reports
- Nothing you type is saved or sent anywhere
- Worked examples you can check by hand
Energy and nutrition
Which calculators help with calories and nutrition?
Start with your maintenance calories, then split them into macros and check your protein. The BMR calculator shows the resting energy equations side by side if you want to see where the numbers come from. Each page explains its method, its limits and when to ask a doctor or dietitian instead.
TDEE calculator
Maintenance calories from resting energy and your activity level.
BMR calculator
Resting energy by Mifflin-St Jeor, Harris-Benedict and Katch-McArdle.
Macro calculator
Calories split into protein, fat and carbs, protein first.
Protein calculator
Daily protein by body weight and goal, with vegetarian sources.
Calorie deficit calculator
A daily calorie target for losing weight at a pace you choose.
BMI calculator
BMI with the WHO and the Asian and Indian cut-offs, and its limits.
Ideal weight calculator
Four ideal weight formulas beside the healthy BMI range.
Water intake calculator
Daily water from the adequate intakes, plus training and heat.
Strength and body
Which calculators help with training and body composition?
The one-rep max calculator estimates your best single lift from a set of up to ten reps and turns it into training percentages. The body fat calculator estimates body fat from a few tape measurements. Both show how accurate their methods are, because estimates of strength and body fat carry real error.
One-rep max calculator
Estimated 1RM by four formulas, with a percentage table.
Body fat calculator
Body fat from waist, neck and hip measurements.
Heart rate zone calculator
Maximum heart rate and zones by % of max or heart rate reserve.
VO2 max calculator
VO2 max from a 12-minute run, a mile walk or your heart rate.
RPE chart
Reps in reserve and the % of 1RM for each RPE.
DOTS and Wilks calculator
Powerlifting totals compared across body weights.
Plate calculator
The plates to load on each side for a target weight.
Coaching business
Which calculators help coaches run their business?
Two tools are for coaches rather than their clients. The income calculator turns clients and packages into monthly take-home after software and payment fees, with your real hourly rate. The capacity calculator works out how many clients your weekly hours can serve well before quality slips.
How they are built
How are these calculators built?
Each calculator uses a method from a peer-reviewed paper or an official report, and its page shows the formula, a worked example, the limits and the sources. The maths is unit-tested against hand-worked values. Calculations run in your browser: nothing you type is saved, sent to Trainaq or used for anything else.
- Formulas and a worked example on every page
- Sources linked from journals and official reports
- Health estimates come with their limits and when to see a professional
FAQ
Free tools FAQ
Are these calculators accurate?
They are as accurate as the published methods behind them, and each page says how accurate that is. Equations predict the average person with your measurements, so treat any result as a starting point and check it against real data, such as your weight trend or the reps you actually complete.
Do you save what I enter?
No. The calculations run in your browser and nothing you type is stored, sent to Trainaq or shared. Reload the page and the fields go back to their example values. The site uses no tracking on these pages, so your numbers stay on your device unless you write them down yourself.
Can coaches use these numbers with clients in Trainaq?
Yes. Coaches set each client’s calorie and macro targets in Trainaq, and the client logs food against them in the free Trainaq app. Strength numbers feed programs, where clients see last time’s weights and the app flags personal records. The calculators are free for anyone, with or without a Trainaq account.
