1RM calculator
Estimate your 1RM — without a max attempt
Estimate your one-rep max (1RM) from a regular set: weight and reps are enough. Based on the Epley and Brzycki formulas — including a table of training weights per intensity.
Your estimated 1RM
| % of 1RM | Weight | Typical reps |
|---|---|---|
| 95 % | – kg | 2 |
| 90 % | – kg | 4 |
| 85 % | – kg | 6 |
| 80 % | – kg | 8 |
| 75 % | – kg | 10 |
| 70 % | – kg | 12 |
| 65 % | – kg | 15 |
| 60 % | – kg | 15–20 |
And who remembers your sets?
Myron is your voice-powered training log: "Hey Myron, eighty kilos, eight" — set logged, rest timer running on your Apple Watch. With progress charts per exercise and muscle group.
How the 1RM calculator works
The calculator uses two established estimation formulas: Epley (weight × (1 + reps ⁄ 30)) and Brzycki (weight × 36 ⁄ (37 − reps)) — the headline number is their mean, and the table weights are rounded to plate-friendly 2.5 kg steps. Up to about 10 reps the formulas are usually within a few percent of the true maximum; beyond that the estimate gets markedly less accurate.
The 1RM is the reference for percentage-based training plans: 3 × 5 at 85% or 4 × 8 at 75% translate directly into kilograms with it. You'll find exercises with clean technique instructions in the exercise directory; how many calories and how much protein support your training is shown by the calorie calculator and protein calculator.
Frequently asked questions
What is the 1RM (one-rep max)?
The maximum weight you can move exactly once with clean technique in an exercise. It is the reference for training intensities: percentages in training plans (e.g. "5 reps at 80%") refer to the 1RM.
Do I really have to test my 1RM?
Not for programming — the estimate from one heavy set is almost always enough in practice. True max attempts are injury-prone for beginners and belong, if anywhere, at the end of a training block: rested, warmed up and with a spotter.
How accurate are 1RM formulas?
At 1–10 reps, Epley and Brzycki are usually within ±5% — provided the set really went close to failure. Above 10 reps and in highly technique-dependent lifts (deadlifts, Olympic lifts) the estimate becomes less accurate.
What do I need the 1RM for in training?
To translate training plans into concrete weights (percent of 1RM) and to measure strength progress without constantly maxing out: if your estimated 1RM rises in the same lift, you are getting stronger.
Formulas: Epley B. (1985): Poundage Chart. Boyd Epley Workout. · Brzycki M. (1993): Strength Testing — Predicting a One-Rep Max from Reps-to-Fatigue. More to look up: exercise directory · methodology & data sources.