Performance calculators
Deterministic fitness math for lifters and runners.
57 calculators for FFMI, DOTS, 1RM, VO2 max, Zone 2, race times, and recovery. Every formula sourced, every limit named.
Free · Private · No signup · 57 tools
Pick your goal
Optimize Body Composition
Optimize body composition with calorie targets that preserve strength while dropping body fat.
Open →Build Strength & Muscle
Build muscle by translating your calorie target into macro and protein plans for strength gains.
Open →Benchmark Your Strength
Benchmark your lifts against DOTS, strength standards, and 1RM projections.
Open →Plan Your Race
Plan race pacing, dial in training paces, and calibrate heart rate zones for distance running.
Open →Recover Better
Recover better by aligning sleep, hydration, and intensity to improve training quality.
Open →Understand Body Composition
Understand body composition with simple estimates that track direction over time.
Open →Worth reading.
Long-form articles
Evidence-backed, sourced, dated.
The 2026 Evidence-Based Programming Guide
Evidence-based programming for 2026: volume, intensity, frequency, and specificity reviewed through the Schoenfeld meta-analyses, with dated caveats.
Zone 2 Training: What the Literature Actually Says
Zone 2 training: polarised work, Seiler's 80/20, Stöggl & Sperlich 2014, and the San Millán mitochondrial framing — separated from the social-media version.
Protein for Lifters: 2026 Dose-Response Meta
Protein for lifters in 2026: dose-response meta-analysis, leucine threshold, distribution across meals, and plant-based adjustments. Sourced.
In under a minute.
Browse all 57 calculators.
FFMI, DOTS, 1RM, VO2 max, Zone 2, race times, recovery — every formula sourced.
FFMI
Calculate Fat-Free Mass Index to gauge muscularity and compare against natural benchmarks.
Open →1RM
Estimate one-rep max with Epley, Brzycki, and Lombardi formulas.
Open →Race Predictor
Race Time predictor: predict finish times across 5K, 10K, half marathon, and marathon from any known race result using Riegel's formula.
Open →