LiftMax

One Rep Max Calculator

Plug in a set you've completed (weight × reps) — see your estimated 1RM and a training-percentage table.

Weight lifted (lb)

Repetitions

Estimated 1 rep max

262.5 lb

% of 1RM	Weight (lb)	Typical reps
100%	262.5	1
95%	249.4	2
90%	236.3	3–4
85%	223.1	5–6
80%	210	7–8
75%	196.9	9–10
70%	183.8	10–12
65%	170.6	12–15
60%	157.5	15+
55%	144.4	15+
50%	131.3	15+

What you entered

Weight lifted: 225 lbReps: 5

1
Epley formula: weight × (1 + reps ÷ 30)
225 × (1 + 5 ÷ 30)= 262.5 lb

Result

Estimated 1 rep max: 262.5 lb

Lifting 225 lb for 5 reps suggests a one-rep max around 262.5 lb — the Epley formula is an estimate, most accurate in the 2-10 rep range, and can drift for very high or very low rep counts.

Estimated one-rep max by weight lifted and reps completed

The Epley formula, 1RM = weight x (1 + reps / 30), applied to common barbell loads. Each column is the estimated max implied by a set taken to that rep count.

Weight lifted (lb)	1RM from 3 reps (lb)	From 5 reps (lb)	From 8 reps (lb)	From 10 reps (lb)
95	104.5	110.8	120.3	126.7
115	126.5	134.2	145.7	153.3
135	148.5	157.5	171.0	180.0
155	170.5	180.8	196.3	206.7
185	203.5	215.8	234.3	246.7
205	225.5	239.2	259.7	273.3
225	247.5	262.5	285.0	300.0
275	302.5	320.8	348.3	366.7
315	346.5	367.5	399.0	420.0

The multipliers are unit-free, so kilograms work identically: 100 kg for 5 reps estimates 116.7 kg. Epley is most reliable between 2 and 10 reps and drifts high above that, and it has no way to know your technique, your fatigue, or how close to failure the set really was. Re-estimate every 4 to 8 weeks, because training percentages taken from a stale 1RM stop driving progress.

How is one rep max calculated?

The Epley formula is the most widely used: 1RM = weight × (1 + reps/30). For example, if you bench press 185 lb for 8 reps: 1RM = 185 × (1 + 8/30) = 185 × 1.267 = 234 lb. The formula is most accurate for 2–10 reps — above 10 reps, it tends to overestimate.

Training percentages from your 1RM

Strength: 80–95% of 1RM for 1–6 reps. Hypertrophy: 65–80% for 6–12 reps. Muscular endurance: below 65% for 12+ reps. Most programs cycle through these phases. For example, at a 300 lb squat 1RM: strength work uses 240–285 lb, hypertrophy uses 195–240 lb.

When to test vs estimate your 1RM

Testing a true 1RM requires a spotter, warm-up sets, and carries injury risk. Estimation from a 3–5 rep set is safer and nearly as accurate. Retest (or re-estimate) every 4–8 weeks as you get stronger, since training percentages from an old 1RM become too easy.

Strength standards by exercise

Common benchmarks for intermediate male lifters (bodyweight multiplier): bench press 1.0–1.5×, squat 1.5–2.0×, deadlift 1.75–2.5×, overhead press 0.65–1.0×. Female lifters typically reach about 60–70% of these multipliers. These are guidelines, not rules.

Frequently asked questions

What is a one rep max (1RM)?

Your one rep max is the maximum weight you can lift for a single repetition with proper form. It's used to calculate training loads — most strength programs prescribe weights as a percentage of your 1RM (like '5 sets of 3 at 85%').

How accurate is the Epley formula for 1RM?

The Epley formula (1RM = weight × (1 + reps/30)) is accurate within about 5% for sets of 2–10 reps. Above 10 reps, all 1RM formulas lose accuracy because they extrapolate too far. For the best estimate, use a set of 3–5 reps.

Should I test my actual one rep max?

For most people, estimating from a 3–5 rep set is safer and almost as accurate. Only test a true 1RM if you're a competitive powerlifter or need an exact number for a meet. Always use a spotter, warm up thoroughly, and don't attempt it when fatigued.

How often should I update my 1RM estimate?

Re-estimate every 4–8 weeks as you progress. Using an outdated 1RM means your training percentages are too low to drive adaptation. Track your best recent sets and recalculate — your training weights should increase as your 1RM estimate climbs.