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1 Rep Max (1RM) Calculator

Estimate your one-rep max from a sub-max set, with a full %1RM training table. Free, no login.

kg lb

Exercise

Weight lifted

Reps performed

Use a true close-to-failure set, 1-12 reps. The formulas degrade above 10.

Formula

Estimated 1RM

— kg

Enter weight and reps to estimate your 1RM

Epley —

Brzycki —

Lander —

Lombardi —

What is a 1 rep max?

Your 1 rep max (1RM) is the maximum weight you can lift one time with proper form for a given exercise. It's the gold-standard reference for strength: powerlifting and weightlifting compete on it, and most strength programs prescribe loads as a percentage of it ("work up to 85% × 5"). Testing a true 1RM is taxing and risky if you're not fresh, well-coached, and properly warmed up — so coaches use estimation formulas that take a sub-max set (say, 100 kg × 5) and predict what the all-out single would be. Four widely used formulas are Epley, Brzycki, Lander, and Lombardi. Each was fit on different lifter populations, so they disagree slightly: Epley tends to read a bit high above 5 reps, Brzycki tends to read low at 10+ reps, Lander sits in between, and Lombardi is more conservative. The honest answer is that all four are estimates — the most useful number is usually the average of all four, or whichever one matches your experience over time. Reliable inputs require a true close-to-failure set; if you stop with reps in the tank, the estimate is too low.

How to use this calculator

1. Pick the exercise (bench, squat, deadlift, OHP, or custom). 2. Enter the weight you lifted and the reps you performed. Use a clean set close to failure — RPE 9 or so — and ideally fewer than 10 reps for the most accurate prediction. 3. Choose which formula to display, or pick "Average" to combine all four. 4. The %1RM table updates with weights for 50% through 100%, with typical rep ranges and training uses (testing, peaking, strength, hypertrophy, endurance, warm-up).

The four formulas

Epley: 1RM = w × (1 + r ÷ 30) Brzycki: 1RM = w × 36 ÷ (37 − r) Lander: 1RM = w ÷ (1.013 − 0.0267123 × r) Lombardi: 1RM = w × r^0.10 where w is the weight lifted and r is the reps performed. All four match closely at 3-5 reps; they diverge at high reps where the underlying assumption (linear strength-endurance relationship) breaks down.

%1RM training table

Fill in your set above and the table shows the working weights for typical training percentages, with the reps each load supports and what that intensity is good for.

%1RM	Weight	Reps	Use
100 %	—	1	Testing / max attempt
95 %	—	2	Peaking / heavy doubles
90 %	—	3-4	Strength
85 %	—	5-6	Strength
80 %	—	7-8	Strength-power
75 %	—	9-10	Hypertrophy
70 %	—	11-12	Hypertrophy
65 %	—	14-16	Muscle endurance
60 %	—	17-20	Muscle endurance
50 %	—	20+	Warm-up / technique

Frequently asked questions

Which formula should I use?

For 1-5 reps, all four are within 2-3% of each other. For 6-10 reps, Epley and Lander tend to read slightly high, Brzycki low — the average usually splits the difference well. Above 10 reps, expect ±5% error or more.

How accurate are 1RM estimates?

For trained lifters using a true close-to-failure set under 10 reps, estimates land within roughly 5% of an actual tested 1RM. For new lifters, untested exercises, or sets stopped well short of failure, the error is bigger.

Should I actually test my 1RM?

If you compete or follow percentage-based programming, periodic max tests (every 6-12 weeks) help calibrate. For general training, estimates from heavy sets of 3-5 are safer and almost as informative.

Why is my deadlift 1RM higher than my squat?

The deadlift uses more posterior-chain mass and starts from a dead stop with no eccentric phase, so most lifters pull more than they squat. Typical strength-trained ratios are roughly bench < OHP × 1.4, squat = bench × 1.3, deadlift = squat × 1.2.

Why does the result drop when I add reps at the same weight?

It shouldn't — more reps at the same weight always implies a higher 1RM. If you're seeing a drop, you probably typed reps without updating weight, or you exceeded the formula's domain (Brzycki requires reps < 37).

Can I use this for accessory lifts like rows or curls?

Yes — pick "Other / custom" and enter the weight and reps. Estimates work for any compound or isolation lift, but they're least accurate for short-range or single-joint movements where neural fatigue dominates.

1 Rep Max (1RM) Calculator