Calculators — Volume 01, free, no sign-up
Calculators with formulas you can read.
Calculators for the math an online coach runs every week. BMR, TDEE, FFMI, 1RM, RPE, macros. Same formulas that ship inside Coach Sheet. The math is on the page so you can verify it.
5 tools live · 5 more on the way
1RM Calculator: Epley, Brzycki, Lombardi side by side
Epley · Brzycki · Lombardi
Estimate your one-rep max from any working set. Three formulas displayed together (Epley, Brzycki, Lombardi) with median output. RIR adjustment for honest non-failure sets. Worked example for a 100 kg × 5 reps RIR 1 set.
FFMI Calculator with Body-Fat Adjustment
Kouri-Adjusted FFMI
Fat-Free Mass Index calculator using the Kouri height-adjusted formula. Includes the natural-ceiling reference for males and females. Worked example with body-fat input via Navy or DEXA-measured percentages.
Macros Calculator: Body-Weight Anchored, Carb-Filled
Body-Weight Anchored
Macronutrient calculator that anchors protein and fat to body weight, then fills carbohydrates from the remaining calorie budget. Cut, maintain, and surplus presets. Worked examples and reasonable g/kg ranges from peer-reviewed research.
RPE Calculator: Map Reps × RPE to Percentage of 1RM
RTS RPE Table
Convert prescribed RPE and reps into a target load via the Reactive Training Systems table. With RIR equivalents, color-coded RPE bands, and worked examples for top sets, back-off sets, and deload weeks.
TDEE Calculator with Mifflin-St Jeor
Mifflin-St Jeor
Total Daily Energy Expenditure calculator using the Mifflin-St Jeor equation (1990). With activity multipliers, three macro variants, and worked examples for cutting, maintenance, and surplus targets.