Free fitness calculators
The numbers every plan starts from - calories, protein, healthy weight and lifting maxes - free, with no sign-up. Use them, then let the coach build the plan around them.
Calorie calculator
Your maintenance calories, a target for fat loss or muscle gain, and a protein / fat / carb split - from the formula dietitians use.
Work it out →Protein calculator
How many grams a day for your bodyweight and goal, split per meal, with a table showing what that looks like in real food.
Work it out →BMI & healthy weight
Your BMI, the NHS band it falls in, the healthy weight range for your height - and an honest note on when BMI is the wrong tool.
Work it out →One rep max calculator
Estimate your max from any set of 1–12 reps without risking a heavy single, then get training weights for every percentage.
Work it out →Macro calculator
Turn a calorie target into grams of protein, fat and carbs - balanced, lower carb, higher carb or your own split - and per meal.
Work it out →Body fat calculator
Estimate body fat from a tape measure (US Navy method), with fat mass, lean mass and the NHS waist-to-height check.
Work it out →Goal weight date
Pick a goal weight and a pace and see the date you could reach it, the milestones on the way, and the daily calorie change it takes.
Work it out →Water intake calculator
Roughly how much to drink today for your size, training, job and the weather - in litres, bottles and mugs.
Work it out →Strength standards
Is your bench, squat, deadlift or press good for your bodyweight? Beginner to elite bands and the next target to chase.
Work it out →Calories burned
Walking, running, weights, football - and site work like bricklaying and labouring - for your bodyweight and time.
Work it out →Steps to calories
What your daily steps burn, how far you walk, and what a few thousand more would be worth in fat over a month.
Work it out →Plate loading calculator
Type the weight you want on the bar and see exactly which plates go on each side - with the plates your gym actually has.
Work it out →Sleep & recovery check
Hours, shift pattern, training days, soreness and stress into one score, with the thing to fix first.
Work it out →Should I bulk or cut?
A straight answer from your body fat (or waist), your goal and how long you have trained - and the calculator to use next.
Work it out →Meal cost calculator
What a week of high-protein home cooking costs against your takeaways and meal deals, and the saving over a year.
Work it out →Rest timer
60s to 5 minutes, beeps and buzzes when time is up, counts your sets. Keep it open in the gym - nothing to install.
Open it →Weight trend tracker
Log daily weigh-ins and see the 7-day average and weekly trend, so the scales stop lying to you. Stays on your device.
Start tracking →Running pace calculator
Pace per km and mile, treadmill speed, and predicted 5k, 10k, half and marathon times from any run.
Work it out →Why these are free
Because the numbers are the easy part. Anyone can tell you that you need 2,100 calories and 160 g of protein a day. The hard part is turning that into meals you will actually cook, sessions that fit around a shift pattern, and adjustments when the scales stall in week three. That is what the Build Me Different coach does, and it starts from exactly these numbers - so try them, see what they say, and if you want the plan built around them, the trial is 30 days free.
How to use them together
Start with the BMI tool if you are not sure whether fat loss or muscle gain is the right first goal. Then run the calorie calculator with that goal to get a daily target, and the protein calculator to make sure the target is built on enough protein. Once you are training, the one rep max calculator tells you what weight to put on the bar.
A note on accuracy
Every formula here is an estimate for the average person. Yours will be within roughly 10% of the truth, which is close enough to start. Track your weight for two weeks, adjust by 100–200 calories if it is not moving the way you want, and you will have a better number than any calculator can give you.
Want the plan built around your numbers?
The AI coach turns these numbers into a full training and meal plan, then adjusts it every week. Free for 30 days.
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