$ train --smarter
Free fitness calculators that just work
Running pace, race predictions, heart rate zones, one rep max, and plate math — fast, accurate, and free. No signup, no spreadsheet required.
Running
Calculate your running pace per mile or kilometer for any distance — 5K, 10K, half marathon, or marathon. Get split times and your target finish time instantly.
Open calculator →Predict your finish time for the 5K, 10K, half marathon, and marathon from a recent race result using the proven Riegel formula.
Open calculator →Heart Rate
Strength
Estimate your one rep max (1RM) for squat, bench press, deadlift, or any lift from a submaximal set. Uses Epley, Brzycki, Lombardi, and O'Conner formulas with a full percentage table.
Open calculator →Enter a target weight and see exactly which plates to load on each side of the barbell, in pounds or kilograms. Supports standard 45 lb and 20 kg bars.
Open calculator →Why RepWorks?
Every calculator here answers a question people actually ask mid-workout: What pace do I need to break 25 minutes in the 5K? What should my heart rate be on an easy run? How much is 85% of my max squat, and which plates do I put on the bar? Each tool gives you the answer in seconds, works on your phone in the gym or on the track, and explains the formula behind the number so you can trust it.
Whether you're training for your first 5K or chasing a marathon PR, building strength or just getting started, these tools are free and always will be.