One Rep Max Calculator for Bench Press, Squat and Deadlift
A one rep max is the heaviest load you can move for a single clean repetition. Testing it is fatiguing and technically risky, so lifters estimate it from a submaximal set. Every estimation formula is a curve fit to real lifting data, and each behaves differently at high rep counts — which is why this tool prints three of them side by side rather than pretending one number is exact.
Estimates diverge more as reps rise — at 5 reps the spread between formulas is 5.0 units.
| % of 1RM | Working weight | Typical rep target |
|---|---|---|
| 95% | 109.8 | 1-2 |
| 90% | 104.0 | 2-3 |
| 85% | 98.2 | 3-5 |
| 80% | 92.4 | 5-6 |
| 75% | 86.7 | 6-8 |
| 70% | 80.9 | 8-10 |
| 65% | 75.1 | 10-12 |
| 60% | 69.3 | 12-15 |
Epley vs Brzycki vs Lombardi
Epley is linear and slightly generous above 8 reps. Brzycki is conservative and considered the most reliable in the 2-8 rep window used by most strength programmes. Lombardi uses a power curve and tracks better for high-rep endurance sets. Below 6 reps all three agree within a couple of percent; at 12 reps they can disagree by 8-10%.
Why lift selection changes reliability
Deadlifts have the flattest strength curve, so a 5-rep set predicts the single well. Bench press fatigues faster because of the smaller muscle mass and stretch-shortening contribution, and overhead press degrades fastest of all. Treat estimates from squats and deadlifts as tighter than estimates from pressing movements.
Programming from the percentage chart
Classic linear programmes sit at 75-85% for volume work and touch 90%+ only in peaking blocks. 5×5 lands around 80%, a hypertrophy 4×8 around 72-75%, and speed work uses 50-60% with compensatory acceleration. Recalculate after each mesocycle rather than after each personal best.
Reps-to-percentage reference (Brzycki basis)
| Reps performed | % of 1RM | Multiplier to 1RM | Primary adaptation |
|---|---|---|---|
| 1 | 100% | 1.00 | Maximal strength |
| 2 | 97% | 1.03 | Maximal strength |
| 3 | 94% | 1.06 | Strength |
| 5 | 89% | 1.13 | Strength |
| 6 | 86% | 1.16 | Strength / hypertrophy |
| 8 | 81% | 1.24 | Hypertrophy |
| 10 | 75% | 1.33 | Hypertrophy |
| 12 | 71% | 1.41 | Hypertrophy / endurance |
People also ask
How many reps should I use for the most accurate 1RM estimate?
Three to six reps taken close to technical failure gives the tightest estimate. Sets above eight reps are limited by local muscular endurance rather than maximal force, so the projection drifts high.
Is it safe to test a true one rep max?
For trained lifters with stable technique and a spotter, occasional testing is fine. Beginners gain nothing from it — estimated maxes from a 5-rep set are accurate enough to programme with and far less fatiguing.
Why is my bench press estimate higher than what I can actually lift?
Pressing strength decays faster with fatigue than the formulas assume, and a paused competition bench is typically 3-6% lower than a touch-and-go set.
Three worked examples
Same engine, three different starting points — useful if you want to see how sensitive the answer is before you type your own numbers in.
Example 1: weight lifted 78 kg / lb, lift "Bench press"
On the lower / more conservative end. Estimates diverge more as reps rise — at 5 reps the spread between formulas is 3.9 units.
Example 2: weight lifted 100 kg / lb, lift "Bench press"
A typical middle-of-the-road setup. Estimates diverge more as reps rise — at 5 reps the spread between formulas is 5.0 units.
Example 3: weight lifted 130 kg / lb, lift "Back squat"
On the higher / more demanding end. Estimates diverge more as reps rise — at 5 reps the spread between formulas is 6.5 units.
Quick answers about the One Rep Max (1RM) Calculator
What exactly does the One Rep Max (1RM) Calculator work out?
A one rep max is the heaviest load you can move for a single clean repetition. You enter lift, weight lifted and repetitions completed and the result panel updates straight away, so you can compare two or three versions of the same question in a few seconds.
What do I need before I start?
Only 3 fields: lift, weight lifted and repetitions completed. Nothing else is needed and nothing is stored.
How is it calculated — epley vs Brzycki vs Lombardi?
Epley is linear and slightly generous above 8 reps. The same maths runs inside this page, so hand-checking the result on paper gives you the identical figure.
Why do two calculators give me different answers for one Rep Max (1RM)?
Deadlifts have the flattest strength curve, so a 5-rep set predicts the single well. Different sites pick different assumptions, so always check which method a calculator states before you trust the gap between two numbers.
What does the "Reps-to-percentage reference (Brzycki basis)" table on this page tell me?
It is the reference range this tool works against — 8 rows from "1" (100%) up to "12" (71%). Use it to sanity-check whether the number you just calculated sits where you expected it to.
Which lift should I pick?
The dropdown offers 4 choices — Bench press, Back squat, Deadlift and Overhead press. Pick the one that matches your real situation rather than the one you would like to be true; lift usually moves the final figure more than any other single input, so it is worth running it twice with the option above and below your guess.
Do I have to press a button or reload the page to see the result?
No. One Rep Max (1RM) Calculator runs completely inside your browser, so the moment you change a value the cards recalculate — there is no submit step, no page reload and no waiting for a server round trip. That also means it keeps working on a weak or intermittent mobile connection.
Is it free, and do you keep what I type?
It is free with no sign-up, no app install and no usage limit. Nothing you enter into One Rep Max (1RM) Calculator leaves your device — the calculation is JavaScript running locally, so there is no upload of your figures to DrHint or anyone else.
Can I use it on a phone?
Yes — the layout stacks to a single column on small screens and the number fields open the numeric keypad on both Android and iOS. Many people bookmark this page or add it to their home screen and re-open it whenever the question comes up.
Anything to be careful about with the result?
Three to six reps taken close to technical failure gives the tightest estimate. Treat the output as a well-grounded estimate for planning, not as a professional, legal or medical decision on its own.
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