Every free online fitness calculator here runs on your own phone or computer, so you can work out training maxes, macros and race splits without handing over your body measurements. Nothing you type is uploaded, and no sign up, email confirmation or cookie banner stands between you and a result.
Estimate a training max with the One Rep Max Calculator, which uses Epley, Brzycki and the other standard formulas, then take that number straight to the Barbell Plate Loading Calculator to see exactly which plates go on each side of the bar. On the nutrition side, the Body Fat Calculator (Navy), the Macronutrient Calculator and the Protein Intake Calculator ask for height, weight and tape measurements that never leave your device.
A one rep max calculator gives an estimate, not a number you have actually lifted, and the standard formulas do not all land in the same place. That is why the One Rep Max Calculator shows Epley, Brzycki and the others together, so you can compare before you load the bar. The Body Fat Calculator (Navy) works the same way: tape measurements are only as consistent as your technique, so measure the same way every time.
Endurance training gets the Swim Pace Calculator for 100m splits, the Rowing Split Calculator for Concept2 500m pace and Cycling Power Zones built from your FTP. For the pub sports there is a Dart Checkout Calculator covering finishes from 170 down and a Bowling Score Calculator that handles strike and spare carryover correctly across all ten frames. Because the sums are done by your own device, they keep working if your signal drops in the gym basement or at the pool.
They are accurate to within roughly five percent of a true max when you enter a set of three to eight reps taken close to failure. Accuracy falls off sharply above ten reps, because the formulas were built from low rep data. Different formulas also disagree with each other, so the One Rep Max Calculator shows several estimates side by side and you should treat the range, not a single number, as your training max.
No. Every calculation is done by your own phone or computer, so the numbers you type into the Body Fat Calculator, Macronutrient Calculator or Protein Intake Calculator are never sent to us or anyone else. There is nothing to submit, no account, and nothing tracking your inputs. Close the tab and the numbers are gone. That matters because body composition and weight figures are health data that most calculator sites send off to their own computers.
The Navy method needs your height plus a neck and waist measurement for men, and height plus neck, waist and hip measurements for women. Use a flexible tape held snug but not squeezing the skin, measuring at the narrowest point of the neck and across the navel for the waist. It typically lands within three to four percent of a DEXA scan, which makes it useful for tracking change over time rather than giving one exact figure.