1RM calculator
Estimate your one-rep max from any hard set. Enter the weight and the reps you lifted it for. No max-out attempt required.
In Mekimeki an estimated 1RM is calculated on every set you log, free, using Brzycki, Epley or a hybrid of the two — the formulas are written out here.
- Lowest of seven formulas
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- Average of seven
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- Highest of seven
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Your training percentages
Percentages of your estimated 1RM, with the rep count each is typically good for. Programs prescribe sets like "5 reps at 80%". This is that table, filled in for you.
| % of 1RM | Weight | Typical reps |
|---|---|---|
| 95% | - | 2 |
| 90% | - | 4 |
| 85% | - | 6 |
| 80% | - | 8 |
| 75% | - | 10 |
| 70% | - | 12 |
| 65% | - | 15 |
All seven formulas, side by side
No 1RM formula is magic. Each one was fitted to a different dataset, so a small disagreement is normal. Looking at the range is more useful than pretending one number is exact: the spread shows you how rough the estimate really is.
| Formula | Estimated 1RM | Character |
|---|---|---|
| Brzycki (1993) | - | Conservative above 10 reps |
| Epley (1985) | - | The most widely used |
| Lombardi (1989) | - | A power curve, not a linear fit |
| Lander (1985) | - | Close to Brzycki at low reps |
| Mayhew (1992) | - | Fitted on bench press data |
| O'Conner (1989) | - | The most conservative here |
| Wathen (1994) | - | Reads highest at high reps |
What problem does this solve?
Most good programs prescribe loads as percentages: "5 reps at 80%". Without a 1RM number, you can't turn a program into actual weights on the bar. Testing a true max gives you that number, but it's fatiguing, risky, and disrupts a training week.
An estimated 1RM solves both problems. Any hard set you've already done becomes a strength number you can plan loads from and compare over time. The percentage table above turns it straight into training weights.
What more do you get in Mekimeki?
The app doesn't just run this formula once. It runs it on everything you do:
- Zero manual entry. Every working set you log updates your estimated 1RM automatically.
- PRs flagged in the moment. When a set implies a new best e1RM, Mekimeki tells you mid-session.
- Trends, not snapshots. Per-exercise e1RM history shows whether your strength is actually climbing.
The formulas
Brzycki: 1RM = weight × 36 ÷ (37 − reps). Epley: 1RM = weight × (1 + reps ÷ 30). The hybrid result averages the two. All of them model the same idea: the more reps you can do at a weight, the higher the single-rep strength it implies.
How accurate are 1RM calculators?
Estimates are most accurate for sets of 2–6 reps. Above 10 reps the error grows, because the weight–reps relationship varies between lifters and exercises. Treat the result as a consistent yardstick for tracking progress, not a guaranteed max.
Which 1RM formula should I use?
Brzycki is slightly more conservative at higher reps; Epley slightly more generous. It matters less which one you pick than that you keep using the same one, so your trend stays comparable.
Should I test my real 1RM instead?
Rarely. A true max attempt is fatiguing, riskier, and disrupts a training week. An estimated 1RM gives you the same signal (is my strength going up?) from the working sets you were already doing.
Stop calculating. Start tracking.
Mekimeki estimates your 1RM from every set you log, with the same formulas, and flags new PRs the moment you hit them.
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