How do I calculate my one-rep max?

From a heavy set taken near failure. Epley gives weight × (1 + reps ÷ 30); Brzycki gives weight ÷ (1.0278 − 0.0278 × reps). Bench pressing 90 kg for 5 reps estimates roughly 105 kg by Epley and 101 kg by Brzycki, so the honest answer is a 101–105 kg range.

Which 1RM formula is most accurate?

They agree closely below about six reps and diverge above ten. Rather than choosing one, take both and treat the spread as your uncertainty. The bigger factor is the set you estimate from — three to five reps near failure is far more reliable than fifteen.

Should I test my actual one-rep max?

Most people do not need to. Estimating from working sets gives you everything programming requires without the fatigue or injury risk. Competitive lifters and those whose sport requires a verified figure are the real exceptions. If you do test, use a spotter or safety pins and stop when form breaks.

Why does my 1RM change day to day?

Sleep, nutrition, hydration, stress and accumulated training fatigue all move maximal strength by a few percent. A lower number on a given day reflects readiness, not lost strength, and reprogramming around a bad day is a mistake.

What percentage should I train at?

It depends on the goal. Roughly 85–95% for maximal strength at low reps, 70–85% for a strength and size mix at moderate reps, and 60–70% for endurance and work capacity. These are averages — rep capacity at a given percentage varies by lift and by individual.

1 Rep Max Calculator — Bench Press, Squat, Deadlift

Calculate your 1 rep max (1RM) for any lift using the Epley, Brzycki, and Lander formulas. Get your full training percentage chart.

Weight Lifted (lbs)

Reps Completed

Lift

Estimated 1 Rep Max

257 lbs

Bench 1RM

263 lbs

Epley Formula

253 lbs

Brzycki Formula

231 lbs

90% (sets of 3)

206 lbs

80% (sets of 5)

Your estimated 1RM is 257 lbs. Use the chart below to plan your training percentages.

Training Percentage Chart

100% — 1 rep

257 lbs

95% — 2 reps

244 lbs

90% — 3 reps

231 lbs

85% — 4 reps

219 lbs

80% — 5 reps

206 lbs

75% — 6 reps

193 lbs

70% — 8 reps

180 lbs

65% — 10 reps

167 lbs

60% — 12 reps

154 lbs

Analysis & insights

Based on 225 lbs × 5 reps, your estimated 1RM is 257.16512660287697 lbs (averaged across the Epley, Brzycki, and Lander formulas). Tight estimate — formulas are most reliable at low reps. For programming: 80% = working set strength, 70% = hypertrophy, 90% = competition singles. Re-estimate every 1-3 months as you progress.

Estimated 1RM: 257.16512660287697 lbs

Averaged across three standard formulas. Formulas converge well for 1-10 rep ranges; above 10 reps they over-estimate.

Industry benchmarks

Estimated 1RM (avg)257.16512660287697 lbs
Epley formula262.5 lbs
Brzycki formula253.15031503150314 lbs
Lander formula255.8450647771277 lbs
Your test225 lbs × 5 reps

Key insights

Formulas under-estimate at high reps

You tested 5 reps. Estimates are most accurate at 1-5 reps, decent at 6-10, and increasingly approximate above 10. If your test was at 12+ reps, treat the 1RM as a rough ceiling, not a target to attempt.

Test true 1RM with a spotter

Formula estimates are useful for programming, but a true 1RM test (built up over 3-4 single attempts on a planned day) gives you the real number. Always with a spotter for bench, squat, and overhead.

Don't test 1RM weekly

True 1RM attempts are extremely stressful on the central nervous system. Test 2-4 times per year max for most lifters. Use estimated 1RM for programming the rest of the year.

Recommended actions(3)

Program training intensity by %1RM

High priority

Standard ranges: strength 80-95% 1RM × 1-5 reps. Hypertrophy 65-80% × 6-12 reps. Power 50-80% × 1-5 reps (moved fast).

Impact: Using percentages avoids the trap of always going to failure — sustainable progress requires "leaving reps in reserve" most sessions.

Track all working sets

High priority

Note weight, reps, and RPE (rate of perceived exertion 6-10) for each set. Patterns over weeks reveal progress and overreaching.

Re-estimate quarterly

Medium priority

Use your best recent set of any rep range as a new 1RM input. Watching the number climb is one of the best motivators in lifting.

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This tool is for informational purposes only and does not constitute medical advice. Consult a healthcare professional for advice specific to your situation.

What is One-Rep Max (1RM)?

Your one-rep max is the heaviest weight you can lift once with acceptable form. It matters because most strength programming is written as a percentage of it — "work up to 80% for three sets of five" is meaningless without a number to take 80% of.

Testing a true 1RM is taxing and carries real injury risk, particularly without a spotter or without competition-level technique. So most lifters estimate it instead, from a heavier set taken close to failure. That is what these formulas do.

The estimates are reliable in a narrow window and drift badly outside it. Predicting from a set of three is accurate; predicting from a set of twenty is close to guesswork, because at high repetitions you are measuring muscular endurance rather than maximal strength.

The formula — how to calculate One-Rep Max (1RM)

Epley: 1RM = weight × (1 + reps ÷ 30) Brzycki: 1RM = weight ÷ (1.0278 − 0.0278 × reps)

weight: = the load lifted
reps: = repetitions completed with good form, at or very near failure

Both are only meaningful if the set was genuinely close to failure. A set of five with three left in reserve estimates the 1RM of someone lifting a much heavier weight, not yours.

Step-by-step example

01You bench press 90 kg for 5 clean reps, at roughly one rep short of failure.
02Epley: 1RM = 90 × (1 + 5 ÷ 30) = 90 × 1.1667 ≈ 105 kg.
03Brzycki: 1RM = 90 ÷ (1.0278 − 0.0278 × 5) = 90 ÷ 0.8888 ≈ 101 kg.
04The two disagree by about 4 kg, which is typical and honest — take the range, roughly 101–105 kg, rather than a single figure.
05Now the same weight for 12 reps: Epley gives 90 × 1.4 = 126 kg; Brzycki gives 90 ÷ 0.694 ≈ 130 kg.
06That number should be treated with real suspicion. At twelve reps you are testing endurance, and the formulas systematically overestimate maximal strength.

Percentage training zones

Typical relationship between load and reps

% of 1RM	Reps usually possible	Primary adaptation
95–100%	1–2	Maximal strength, neural
90–95%	2–4	Strength
85–90%	4–6	Strength with some size
80–85%	6–8	Strength and hypertrophy
70–80%	8–12	Hypertrophy
60–70%	12–20	Endurance, work capacity

These are averages. Rep capacity at a given percentage varies substantially by lift and by individual — leg press tolerates far more reps at 80% than a heavy deadlift does.

Which formula, and when to distrust both

Epley and Brzycki produce nearly identical results at low repetitions and diverge as reps climb. Below about six reps the difference is usually within a couple of percent, which is why estimating from a set of three to five is the standard advice.

Beyond ten reps, both lose reliability. Epley tends to run slightly higher and Brzycki slightly lower at high rep counts, but the more important point is that neither is measuring the same quality any more. Someone with excellent endurance and modest peak strength will have their 1RM overestimated badly.

The estimates also behave differently across lifts. Deadlift and squat 1RMs tend to be predicted reasonably; bench press somewhat less so; and isolation movements poorly, because technical failure and muscular failure diverge.

Estimate from a set of 3–5, not from a high-rep set

The single biggest improvement you can make to a 1RM estimate is to take it from a heavier set of three to five reps rather than a light set of fifteen. The formula does not become more accurate with more data points — it becomes less accurate as the rep count rises.

Testing safely, if you test at all

Most lifters do not need a true 1RM. Estimating from working sets provides everything programming requires without the fatigue cost or the risk. Competitive lifters and anyone whose sport requires a verified number are the genuine exceptions.

If you do test, the fundamentals are unglamorous: warm up thoroughly with ascending singles, rest three to five minutes between attempts, use a spotter or safety pins on bench and squat, and stop the moment form breaks rather than grinding a rep that is already lost. A missed lift with good positioning is a normal training event; a missed lift with a rounded spine is an injury.

Expect your 1RM to fluctuate day to day by a few percent based on sleep, nutrition and accumulated fatigue. A number measured on a bad day is not a decline in strength, and reprogramming around it is a mistake.

Key considerations

Estimate from a set of three to five reps for the most reliable result.
The set must be genuinely close to failure or the estimate is meaningless.
Treat the two formulas as a range rather than picking whichever is higher.
Expect day-to-day variation of a few percent from sleep, food and fatigue.
Re-estimate every four to six weeks rather than every session.
Use a spotter or safety pins for any genuine maximal attempt.
Estimates are least reliable on isolation lifts, where technical and muscular failure diverge.

Common mistakes to avoid

Estimating from a high-rep set, where the formulas measure endurance rather than strength.
Using a set that was several reps short of failure, which inflates nothing and simply misestimates.
Picking the higher of the two formula outputs as your number.
Testing a true max frequently, which costs recovery for no programming benefit.
Programming from a stale figure months out of date.
Grinding a failing rep with broken form rather than racking it.

Frequently asked questions

Sources & references

Written and fact-checked by the CalcProLabs Editorial Team. Read our calculation methodology and editorial policy.

Last updated July 28, 2026