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One Rep Max Calculator
Estimate the most you could lift for a single repetition without having to test it. Enter a weight and the number of reps you completed with good form; you get your one-rep max by the Epley formula, the Brzycki and Lombardi estimates, and a table of training percentages.
- Brzycki
- 253.1 lb
- Lombardi
- 264.3 lb
Percentages of your one-rep max (Epley)
| % of 1RM | Weight (lb) | Weight (kg) |
|---|
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Your recent calculations
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Formula
How to use it
- Enter the weight you lifted, in pounds or kilograms.
- Enter the number of full reps you completed in one set taken close to failure.
- Read your estimated one-rep max and use the table to pick working weights at a percentage of it.
Worked examples
225 lb for 5 reps (Epley 262.5 lb, Brzycki 253.1 lb)
- One-rep max (Epley)
- 262.5 lb
- Brzycki
- 253.1 lb
- Lombardi
- 264.3 lb
100 kg for 8 reps
- One-rep max (Epley)
- 279.3 lb
- Brzycki
- 273.7 lb
- Lombardi
- 271.4 lb
Getting a reliable estimate
The formulas are most accurate for sets of about 2 to 10 reps. Beyond that, endurance rather than strength starts to decide how many reps you get, and the estimates drift apart. Epley and Brzycki give exactly the same answer at 10 reps; below that Epley is slightly higher, above it Brzycki is.
Estimates also vary by lift and by lifter. Treat the number as a guide for choosing training loads, and build up to any true maximum attempt with a spotter or safety bars.
Using the percentage table
Programs often prescribe loads as a percentage of one-rep max — for example sets of 5 at around 80–85%, or sets of 8–10 at around 70–75%. The table lists each 5% step in both pounds and kilograms; round to the nearest plate you can load.
Questions people ask
What is my one-rep max if I lift 225 lb for 5 reps?
About 262.5 lb by Epley (225 × 1.1667) and about 253 lb by Brzycki (225 × 36 ÷ 32).
Which 1RM formula is most accurate?
None is consistently best. They agree closely for sets of 10 reps or fewer — Epley and Brzycki are identical at 10 reps and within about 4% of each other below that — so either is a reasonable guide for choosing training loads.
How many reps can I do at 80% of my max?
Rearranging the Epley formula gives about 7 to 8 reps at 80%, about 5 at 85% and about 3 at 90%, though this varies between people and lifts.