Strength and nutrition calculators

Built on the same math as the app

Every calculator here uses the formulas the Muscla app uses, and the same test cases check both. The one-rep max you see on this site is the one Muscla shows after a set, and the calorie target follows the same rules as the app’s onboarding.

Each page shows the formula with your own numbers, explains how accurate the result is and lists the studies behind it. There are no ads and no tracking cookies.

Which calculator do you need?

• Starting a strength program? Estimate your one-rep max from a recent hard set, then use the rep table to pick your working weights.
• Changing your body weight? The calorie calculator gives your maintenance calories and a daily target for losing or gaining at a pace you choose.
• Building muscle or keeping it while you diet? The protein calculator turns your weight and goal into grams per day and per meal.
• Tracking progress beyond the scale? The body fat calculator estimates your body fat from a few tape measurements.
• Standing in front of the bar? The plate calculator tells you which plates go on each side, including a warm-up.

How the calculators fit together

The five calculators work on their own, and some of them pass your numbers on to the next one, so you do not type them twice.

• One-rep max to plate calculator. Your estimated max carries over to the plate calculator, which shows the plates that make up that weight on the bar. Change the number to the weight your program asks for.
• Calorie calculator to protein calculator. The protein calculator takes your weight and your goal from the calorie calculator, then turns them into grams of protein per day and per meal.
• Body fat to calorie calculator. The body fat calculator hands your height and weight to the calorie calculator, so your maintenance calories start from the same body.

You can also work through them in this order: estimate your body fat, set your calories, check your protein and then plan the bar for your main lifts. Each page works just as well alone. Every link keeps the units you chose, kilograms or pounds.

A starting point, not a verdict

A formula knows your numbers, not your body. Use the results to start, then let your training log and your weight trend correct them. That is what Muscla does for you: it adjusts your weights after every workout and checks your calorie target against your weight each week.