One-rep max calculator

One hard set. See what you’re capable of.

START HERE

Your last set.

Quick-set reps1–12

Use clean reps close to failure. Estimate only.

Your estimated 1RM

Updates live

Estimated one-rep max 116.7 kg. Epley. 5 reps. high confidence.

257.2 lb

Your strength curve

8 reps
Estimated rep max

92.1 kg × 8 reps

79% of 1RM92.5 kg rounded

More reps, less weight. The same estimated strength.Rep maxes assume a hard set.

High confidence · Estimated, not tested.

90% training max 105 kgrounded

PUT YOUR STRENGTH IN PERSPECTIVE

See where you stand.

One lift. A bigger picture. Find your level and what comes next.

Compare with

Strength relative to bodyweight. For this exercise, in your selected group.

YOUR STRENGTH, IN CONTEXT

Every lifter has a place to start.

Your result lights up herePick a group to see the distribution

Choose your exercise, then add your bodyweight and comparison group.

Your next chapter.

Benchmarks. Your own pace.

Select a supported exercise to see its strength benchmarks.

Data from Strength Level’s published bodyweight-ratio standards for people who log lifts there. Not the general population. No age adjustment. Approximate. How it works

Training load tablesPercentages & rep maxes

Training percentages

Based on your Epley 1RM. Loads rounded to 2.5 kg increments; exact values shown alongside.

Training percentages from the estimated 1RM
%LoadExact~RepsPurpose
100117.5 kg116.71Test / opener
95110 kg110.82Heavy singles
90105 kg1054Heavy triples–fours
85100 kg99.26Strength work
8092.5 kg93.38Strength / volume
7587.5 kg87.510Hypertrophy
7082.5 kg81.7~11Hypertrophy / technique
6575 kg75.815Technique / endurance
6070 kg70AMRAPGeneral / deload
5565 kg64.2AMRAPWarm-up
5057.5 kg58.3AMRAPWarm-up / speed

Estimated rep maxes

Predicted maximum weight for each rep target, using Epley.

Estimated n-rep maxes from the active formula, 1 to 10
nRMLoad% of e1RM
1116.7 kg100%
2109.4 kg94%
3106.1 kg91%
4102.9 kg88%
5 (this set)100 kg86%
697.2 kg83%
794.6 kg81%
892.1 kg79%
989.7 kg77%
1087.5 kg75%
Compare all seven formulas 5.6% spread

Select a formula to make it active. Their spread is disagreement, not a confidence interval.

Why this calculator

Why this is the best 1RM calculator

Most 1RM calculators hide the equation and sell you a number. This is the best 1RM calculator we have ever used.

It names seven published formulas, tells you when the estimate is junk, ranks 107 lifts against published standards, and uses the same math the LIFTAG log will keep using next week.

If another calculator does all of that, use it. We have not found one.

  1. Seven named formulas, live

    Epley is the default so the website and the app agree. Switch to Brzycki, Lombardi, Mayhew, O’Connor, Wathen, or Lander on the same set. The spread is disagreement between equations, not a confidence interval.

  2. Confidence that follows the set

    A hard 5 is high confidence. A 12 is rough. A 20 is labeled endurance, not a max. Reynolds, Gordon, and Robergs 2006 found 5RM beat 10RM beat 20RM. This page says so before you program from a burnout.

  3. 107 lifts, ranked with receipts

    Pick the exercise, enter bodyweight, choose a comparison group. You get “stronger than X% of lifters” from published Strength Level ratios, interpolated between the 5th and 95th. Past elite, a sourced world-record ratio is 100% when we have one.

  4. The website and the log agree

    Same Epley estimator the LIFTAG app stores per exercise. Training loads round to 2.5 kg or 5 lb. Calculated on your device. No signup. The worked example, 100 kg × 5 = 116.7 kg, is true with JavaScript off.

Make progress a habit. Track your sets. Watch your max grow.

Track with LIFTAG

What a 1RM is, and what a PR is

A one-rep max is the most you can lift once, with the standard you actually compete or train with. A PR is any personal record: a 5-rep bench, a paused squat, a volume day. People search “PR calculator” when they mean this tool. It estimates a 1RM. LIFTAG stores both.

You do not need a meet to use the number. You need a hard set of a few reps, a named formula, and a log that does not invent a second max next week.

How to use this calculator

Weight, reps, units

Type the load and the clean reps. Switch kg or lb; the physical weight stays put. The result updates as you type. No submit button, no email gate, no app wall in front of the number.

Pick an exercise to compare your strength

In See where you stand, search from 107 common gym exercises with strength benchmarks, across barbell, dumbbell, cable, and machine lifts. Choose a lift, enter your bodyweight, and select a comparison group to see an approximate “stronger than X% of lifters” ranking. Exercise selection changes the comparison, not the 1RM equation.

Why 3–8 near failure beats a 15-rep burnout

Prediction error grows as the set gets longer. A hard 5 is the sweet spot. A 20-rep set measures how long you can last, not what you could unrack once. If you only have a high-rep set, do a heavier one. Then come back.

How LIFTAG estimates 1RM

LIFTAG estimates 1RM with the Epley formula for sets of 1–10 reps near failure. A single is stored as the weight you lifted, not as 3% extra. The website uses the same estimator as the app. Optional RPE is context on the set, not a second formula.

The formula, assumptions, and worked example are also available in a plain Markdown version. Core tracking is free; pricing is the dated fact sheet.

How the strength percentile works

Your estimated 1RM divided by bodyweight gives your strength-to-bodyweight ratio. We compare it with published male or female Strength Level ratios for the selected exercise.

The anchors are the 5th (beginner), 20th (novice), 50th (intermediate), 80th (advanced), and 95th (elite) percentiles. LIFTAG interpolates between them and shows “You are stronger than X% of lifters”. Below the 5th we show “fewer than 5%”. A sourced raw world-record ratio can extend the final 5% to 100%.

This is an approximate benchmark comparison, not a measured population percentile. The source reflects people who log lifts, not everyone. It does not adjust for age, body proportions, or every bodyweight difference. Valid sets are 1–30 reps and bodyweights 30–300 kg; after 10 reps the estimate and ranking are rougher.

Dumbbell loads are per dumbbell, including the handle; goblet squats and dumbbell pullovers use one weight. Machine designs and pulley ratios vary. Pull-ups, chin-ups, and dips use bodyweight plus added weight for a total-load estimate and receive no percentile. Other exercise also gives an estimate only.

All 107 exercise benchmarks and sources

Strength Level standards, reviewed 9 September 2026.

How the formulas work

Epley is the default so the website and the log agree. The comparison table shows six other published equations on the same set. At one rep every formula returns the load you typed.

Worked example, always true without JavaScript: 100 kg × 5. Epley is 116.7 kg. 225 lb × 5 is 262.5 lb.

How the formulas work
FormulaYearExact100 kg × 5
Epley19851RM = w × (1 + r / 30)116.7 kg
Brzycki19931RM = w × 36 / (37 − r)112.5 kg
Lombardi19891RM = w × r^0.10117.5 kg
Mayhew19921RM = 100w / (52.2 + 41.9 e^(−0.055r))119 kg
O'Connor19891RM = w × (1 + r / 40)112.5 kg
Wathen19941RM = 100w / (48.8 + 53.8 e^(−0.075r))116.6 kg
Lander19851RM = 100w / (101.3 − 2.67123r)113.7 kg

Epley (1985)

Linear. 1RM = w × (1 + r / 30). At 10 reps it meets Brzycki at w × 4/3. Below 10 it runs a little high. This is LIFTAG’s default because it is stable, named, and already in the app.

Brzycki (1993)

1RM = w × 36 / (37 − r). Conservative in the middle. Undefined at 37 reps, which is why this page will not show a Brzycki number on a 30-rep set as if it were a max.

The rest of the family

Lombardi is a power curve. Mayhew and Wathen are exponential and were the LeSuer bench winners. O’Connor is a shallower linear (r/40). Lander is the NSCA-era percentage chart in equation form. The LeSuer et al. 1997 paper is still the paper to cite: every formula under-predicted deadlift by about 10%.

When the estimate is wrong

  • High-rep sets. Past 10, uncertainty increases; use a lower-rep set before making decisions.
  • Isolation lifts and machines produce more reps at a given percentage than a free squat.
  • A bounce bench and a paused bench are different standards; the formula cannot see the difference.
  • Squat depth, deadlift start, and grip change the set. Formula disagreement is not a confidence interval.
  • Fatigue, a cut, and poor sleep make the same kilos a different session. That is what RPE is for.

Bench, squat, and deadlift maxes

Select your exercise in the calculator for lift-specific context and strength benchmarks. The 1RM formulas remain the same. Most validation studies focus on bench, squat, and deadlift. A machine chest press 8RM is not a competition bench.

For percentage programs like 5/3/1, use the 90% training max as a conservative reference. The best workout app for powerlifting guide covers how that looks in a log.

How to test a true 1RM

  1. Warm up to a heavy triple you already own.
  2. Take small jumps and leave a rep in reserve until the last attempt.
  3. Use a spotter and safeties. Set safety pins before adding load.
  4. Log the single. LIFTAG stores it as the max, not as an estimate.

Most weeks you should skip this. Log submax work, watch estimated 1RM trend, and add load when the overload is honest.

How LIFTAG uses 1RM

Every working set can update estimated 1RM for that exercise. The app uses Epley per set, just like this page. PRs stay on the lift you performed, and percentage cues read that history. Partner-gym NFC and QR tags open the right exercise.

Get the app. Core tracking is free on iOS and Android. Estimated 1RM is not paywalled.

Frequently asked questions

Take a hard set of 2–10 reps and run Epley: 1RM = weight × (1 + reps / 30). A 100 kg set of 5 estimates 116.7 kg. It is an estimate, not a tested single.

Method

Written by the LIFTAG team, Bratislava. Last reviewed September 11, 2026. First published September 9, 2026. We log estimated 1RM with Epley. This page shows the rest of the family so you can see the spread. Facts and how to cite us: about, press kit. about, press kit. Questions: support. support.