One-Rep Max Calculator
Estimate your one-rep max (1RM) for any lift using the Epley formula, with a percentage table for training loads.
| Reps | % of 1RM | Estimated Weight |
|---|---|---|
| 1 | 100% | 216 lb |
| 2 | 95% | 205 lb |
| 3 | 93% | 201 lb |
| 4 | 90% | 194 lb |
| 5 | 87% | 188 lb |
| 6 | 85% | 183 lb |
| 7 | 83% | 179 lb |
| 8 | 80% | 173 lb |
| 9 | 77% | 166 lb |
| 10 | 75% | 162 lb |
Use this table to plan training loads — e.g. 183 lb for a set of about 6 reps.
- 95% of 1RM205 lb
- 90% of 1RM194 lb
- 85% of 1RM183 lb
- 80% of 1RM173 lb
- 75% of 1RM162 lb
- 70% of 1RM151 lb
- 65% of 1RM140 lb
- 60% of 1RM130 lb
The Epley formula is most accurate for sets of 10 reps or fewer — heavier singles and doubles give the most reliable estimate.
ƒShow your work
1RM = weight × (1 + reps ÷ 30)
- 1Weight lifted = 185 lb, Reps completed = 5
- 21RM = 185 × (1 + 5 ÷ 30) = 216 lb
About the One-Rep Max Calculator
A one-rep max (1RM) is the heaviest weight you could lift for a single complete rep, and this calculator estimates it from a lighter set you actually performed, using the Epley formula. It's a prediction extrapolated from submaximal reps, not a measured max — actual 1RM testing involves real risk and fatigue that a formula can't capture, so treat the number as a planning estimate rather than a guaranteed true max.
Lifters use estimated 1RM mainly to program percentage-based training — knowing that a working set at, say, 80% of 1RM should feel a certain way lets you plan progressive overload without maxing out every session, which is both safer and less fatiguing over a training block.
This is general strength-training information, not personalized coaching — form, experience and individual recovery all affect how a real max would compare to the estimate. Your lift numbers are calculated instantly in your browser and never stored.
How it’s calculated
The Epley formula: 1RM = weight × (1 + reps ÷ 30). It's one of several competing rep-max formulas (Brzycki is another common one), and all of them share the same core assumption — that the relationship between weight and reps-to-failure follows a fairly predictable curve — which holds up reasonably well for moderate rep ranges but grows less reliable at the extremes.
Estimates get less accurate the higher the rep count used to calculate them: a set of 3–5 reps predicts 1RM fairly reliably, but a set of 15–20 reps asks the formula to extrapolate much further from what was actually lifted, and fatigue and pacing differences start to matter more than the formula accounts for.
Frequently asked questions
How accurate is a 1RM calculator?
It's generally a solid estimate for sets in the 1–10 rep range, particularly under 5 reps, but accuracy declines the higher the rep count used — a max estimated from a set of 15+ reps is a much rougher guess than one from a set of 3.
Which formula is more accurate — Epley or Brzycki?
Neither is universally more accurate; they tend to agree closely at low-to-moderate reps and diverge more at higher rep counts. Both are reasonable estimates, and neither replaces an actual tested max for precision.
Should beginners test their true 1RM or just estimate it?
Most coaches recommend beginners estimate rather than test a true max early on, since proper technique under near-maximal load takes time to develop and true max attempts carry more injury risk without that foundation. An estimate from a controlled set of 3–5 reps is a safer starting point.
How often should I retest or recalculate my 1RM?
Every few weeks to a couple of months is common for lifters running percentage-based programs, since strength changes gradually — recalculating too often just adds noise, while going too long risks training off an outdated number.
Is my 1RM the same percentage-wise across different lifts?
Not exactly — the relationship between reps and percentage of 1RM can vary somewhat by exercise and by individual, with compound lifts like the squat or deadlift sometimes behaving slightly differently than isolation movements. The percentage table above is a general guide, not an exact rule for every lift.
Related calculators
Powered by GetCalculator.online