Calculators built for athletes.
From the timer you keep open at the rack to research-grade VBT and F-V profiling. Every tool runs in your browser — no signup, no install.
In-session tools
Interval Timer & Stopwatch
EMOM, Tabata, rest timer, custom intervals with audio cues.
Training Metronome
BPM-based metronome for tempo lifts, sprint cadence, and plyometric rhythm.
Running Pace Calculator
Convert pace ↔ time ↔ distance with split tables for common race distances.
Heart Rate Training Zones
5-zone training calculator using HRR (Karvonen) or %MHR — Z1 recovery to Z5 VO2max.
Personal Records (PR) Tracker
Log PRs by lift, auto-compute Epley e1RM, view history. Stored on device.
VO2max Estimator
Estimate aerobic capacity from Cooper run, Rockport walk, or resting HR.
Session Tools
Interval Timer & Stopwatch
EMOM, Tabata, rest timer, custom intervals with audio cues.
Training Metronome
BPM-based metronome for tempo lifts, sprint cadence, and plyometric rhythm.
Heart Rate Training Zones
5-zone training calculator using HRR (Karvonen) or %MHR — Z1 recovery to Z5 VO2max.
Running Pace Calculator
Convert pace ↔ time ↔ distance with split tables for common race distances.
VO2max Estimator
Estimate aerobic capacity from Cooper run, Rockport walk, or resting HR.
Race Time Predictor (Riegel)
Predict your time at any distance from a known performance using Riegel formula.
Strength
1RM Calculator
Estimate 1-rep max from submaximal sets via 4 validated formulas.
Wilks / DOTS Score
Bodyweight-adjusted powerlifting strength score.
Strength Standards by Bodyweight
See where your lifts sit — Untrained to Elite — based on bodyweight ratios.
Barbell Plate Calculator
Which plates to load per side for any target weight. kg and lb support.
RPE ↔ %1RM Chart
Convert reps × RPE to %1RM and target weight (Helms/RTS table).
Velocity / VBT
VBT Velocity Zone
Map mean bar velocity to training zone and %1RM range.
Velocity-Loss Rep Predictor
Predict reps remaining from first-rep velocity and target loss %.
Force-Velocity Profile Builder
Build F-V profile with chart from 3-4 load/velocity pairs.
Power-to-Weight Calculator
Sustained W/kg compared to cycling categories from recreational to world-class.
Jump
RSI Calculator
Reactive Strength Index from jump height and contact time.
Jump Power (Sayers/Harman)
Peak and mean power output from CMJ height and body mass.
EUR (CMJ ÷ SJ)
Eccentric Utilization Ratio — SSC contribution efficiency.
Sprint ↔ Jump Converter
Convert between broad jump, CMJ, and 10/20/30m sprint times.
Planning
Tempo & TUT
Compute total time-under-tension from 4-digit tempo and set/rep.
Macrocycle Planner
12-week backward plan from competition date.
Personal Records (PR) Tracker
Log PRs by lift, auto-compute Epley e1RM, view history. Stored on device.
ACWR Calculator
Acute:Chronic Workload Ratio for injury-risk monitoring (Gabbett 2016).
Recovery
Left-Right Asymmetry (LSI)
Compute Limb Symmetry Index and injury-risk band.
DOMS Onset Predictor
Estimate soreness peak time from session type and load.
Macro Calculator for Athletes
TDEE + protein/carb/fat split tailored to your goal (Mifflin–St Jeor).
Body Fat Estimator (Navy)
Estimate body fat % from circumference measurements (US Navy method).
Sport Calorie Burn
MET-based calorie burn for 30+ sports and training activities.
Daily Recovery Score
Composite readiness from sleep, soreness, mood, motivation, and HRV.
Hydration & Sweat Rate
Daily water needs + exercise-specific sweat replacement (ACSM/ISSN).