Strength, Running & Nutrition Calculators
Free, no-signup fitness calculators. Every tool shows its formula, a worked example you can verify by hand, and honest limitations — no black boxes.
Strength — 1RM & Training
One-rep-max estimates from three validated formulas, plate loading, and percentage charts for programming.
One Rep Max Calculator
Free one rep max calculator: enter weight and reps for an estimated 1RM from three proven formulas (Epley, Brz
Bench Press 1RM Calculator
Bench press 1RM calculator with barbell plate loading: estimate your max from a rep set, then see which plates
Squat 1RM Calculator
Squat one rep max calculator: turn any working set into an estimated 1RM with Epley, Brzycki and Lombardi form
Deadlift 1RM Calculator
Deadlift 1RM calculator: estimate your max pull from a rep set using three validated formulas, with plate load
1RM Percentage Chart
Interactive one rep max percentage chart: enter your 1RM for a full training table from 100% to 50%, with rep
Running — Pace & Race
Pace calculators, converters and race prediction from 5K to marathon.
Running Pace Calculator
Free running pace calculator: enter distance and time to get your pace in min/km and min/mile, plus speed in k
Marathon Pace Calculator
Marathon pace calculator: enter your goal finish time to get the exact required pace per km and mile, plus a 5
5K Pace Calculator
5K pace calculator: get your current pace and Riegel-based predictions for 10K, half marathon and marathon fro
Half Marathon Pace Chart
Half marathon pace chart: pick a goal finish time to see required pace per km/mile and mile splits. Covers 1:3
Pace Converter
Running pace converter: instantly convert between min/km, min/mile, mph and kph. One input, all four units, wi
Nutrition — Calories & Protein
TDEE, bulking and cutting targets and protein intake from peer-reviewed formulas.
TDEE Calculator
Free TDEE calculator using the Mifflin-St Jeor equation: enter sex, weight, height, age and activity level for
Bulking Calorie Calculator
Bulking calorie calculator: start from your TDEE and add a lean 10–20% surplus for muscle gain, with protein t
Cutting Calorie Calculator
Cutting calorie calculator: build a 15–25% deficit from your TDEE for fat loss while keeping muscle, with mini
Protein Intake Calculator
Protein intake calculator: daily protein grams from body weight using the ISSN position stand range of 1.6–2.2
Why TrainMath exists
Most fitness calculators hide one formula behind one number. TrainMath shows the math: three 1RM formulas side by side, Riegel predictions with the exponent visible, Mifflin-St Jeor solved step by step. If a number on this site cannot be checked by hand, it should not be here.