Sports & Performance
One Rep Max (1RM)
Estimate your maximum single-rep lift using the Epley formula.
Knowing your 1RM (one-repetition maximum) lets you calculate training percentages for periodization programs. Most lifters test working-weight performance rather than risking maximal attempts.
Estimated 1RM
216 lbs
- pct90
- 194 lbs (90% — heavy set)
- pct80
- 173 lbs (80% — 8-rep sets)
- pct70
- 151 lbs (70% — 12-rep sets)
Formula and method
Epley: 1RM = Weight × (1 + Reps/30); Brzycki: 1RM = Weight / (1.0278 - 0.0278 × Reps)
Epley formula is most commonly used and accurate for 1-10 reps. Brzycki is more accurate at lower rep ranges. Both are estimates — actual 1RM varies by day, rest, and fatigue.
Worked examples
Bench press working set
- Weight Lifted (lbs):
- 225
- Reps Completed:
- 5
- Formula:
- Epley (most popular)
Estimated 1RM: 263 lbs
Squat heavy triple
- Weight Lifted (lbs):
- 315
- Reps Completed:
- 3
- Formula:
- Brzycki (accurate for 1-10 reps)
Estimated 1RM: 334 lbs
Assumptions and limits
- All reps completed with consistent form
- Accurate rep count (no partial reps)
This tool provides an educational estimate. Rules, rates and personal circumstances can change the answer. Review the assumptions before relying on a result. Report a correction.
Common mistakes to avoid
- Using rep ranges above 10 — these formulas become unreliable above 10 reps.
- Not accounting for technical breakdown under fatigue — the estimate assumes all reps have equal difficulty.
- Using 1RM estimate to set training weights without adjustment — use the percentages as starting points and adjust based on feel.
Frequently asked questions
Is it safe to test my actual 1RM?
For experienced lifters with proper form, yes — with a spotter. For beginners, using the formula is safer. Most powerlifting-style programs use estimated 1RM from working sets to set training weights.
What percentage should I train at?
90%+: maximal strength (1-3 reps). 80-90%: strength (3-5 reps). 70-80%: hypertrophy (6-12 reps). 60-70%: hypertrophy/endurance (12-15 reps). Below 60%: endurance and technique.