One-Rep Max (1RM) Calculator + Training Loads
Estimate your one-rep max from a weight, reps and RPE with Epley, Brzycki, Lombardi and other formulas, plus a 50–95% training-load table and rep maxes.
Training loads
| of 1RM | kg | Used for |
|---|---|---|
| 95% | 108.9 | Strength — up to 6 reps, 2–6 sets |
| 90% | 103.1 | Strength — up to 6 reps, 2–6 sets |
| 85% | 97.4 | Strength — up to 6 reps, 2–6 sets |
| 80% | 91.7 | Muscle growth — 6–12 reps, 3–6 sets |
| 75% | 85.9 | Muscle growth — 6–12 reps, 3–6 sets |
| 70% | 80.2 | Muscle growth — 6–12 reps, 3–6 sets |
| 65% | 74.5 | Muscular endurance — 12+ reps, 2–3 sets |
| 60% | 68.8 | Muscular endurance — 12+ reps, 2–3 sets |
| 55% | 63 | Muscular endurance — 12+ reps, 2–3 sets |
| 50% | 57.3 | Muscular endurance — 12+ reps, 2–3 sets |
Goals by load as the NSCA’s Essentials of Strength Training and Conditioning assigns them.
Rep maxes
| Reps | of 1RM | kg |
|---|---|---|
| 1 | 100% | 114.6 |
| 2 | 95% | 109.4 |
| 3 | 93% | 106.2 |
| 4 | 90% | 103 |
| 5 | 87% | 100 |
| 6 | 85% | 97.1 |
| 7 | 82% | 94.2 |
| 8 | 80% | 91.4 |
| 9 | 77% | 88.6 |
| 10 | 75% | 85.9 |
Warm-up for a max attempt
| Set | of 1RM | kg | Reps | Rest |
|---|---|---|---|---|
| 1 | 40% | 45.8 | 8 | 1 min |
| 2 | 50% | 57.3 | 5 | 2 min |
| 3 | 60% | 68.8 | 4 | 2 min |
| 4 | 70% | 80.2 | 3 | 2 min |
| 5 | 80% | 91.7 | 2 | 3 min |
| 6 | 90% | 103.1 | 1 | 3 min |
| 7 | 95% | 108.9 | 1 | 5 min |
| Attempt | 100% | 114.6 | 1 |
StrengthLog’s warm-up protocol, lightest first; the attempt is the estimate above.
Plates to load
Each side: 25 · 20 · 1.25
On the bar: 112.5 kg
114.6 kg cannot be made with these plates; this is the nearest load under it.
Each side: 25 · 20 · 1.25. On the bar: 112.5 kgPlates assumed, in pairs: 25, 20, 15, 10, 5, 2.5, 1.25 kg.
🔒 Calculated in your browser. Estimates from rep-based formulas — real maxes depend on form, fatigue and the lift. Don't attempt a true max without a spotter.
Estimate your max without maxing out
Enter a weight you lifted and how many reps you managed, and the tool estimates your one-rep max (1RM) — by default the average of the Epley and Brzycki formulas, or, from the "Formula" select, the average of every formula or any one of them, Lombardi, Lander, O'Conner, Mayhew and Wathan included — and shows each formula's own answer beside it. If the set stopped short of failure, set "RPE (how hard the set was)" and the reps you had left are counted before any formula runs. It also builds a percentage table (50–95% of 1RM) so you can pick training loads for your program, and a "Rep maxes" table of the weight the estimate says you should manage at each low rep count. “Show loads in” turns every load on the page into kilograms or pounds, whichever you program in, and the folded “Plates to load” lays out the plates for each side of the bar — kilo discs or pound plates — for the estimate or any load you type. “Save this set” keeps the set and the day in this browser under “Training log”, with its estimate beside it, to set against the next one; each can be opened again or deleted, and “Delete them all” empties it.
An estimate, lift safely
Rep-based estimates get less accurate as reps climb (best under about 10), and real maxes depend on form, fatigue and the lift itself. Use the numbers to program training, and never attempt a true one-rep max without a spotter or safeties. Everything runs in your browser.
The two formulas, and where they disagree
Epley is weight × (1 + reps ÷ 30). Brzycki is weight × 36 ÷ (37 − reps). They cross at exactly ten reps, where both give the same answer, and disagree either side of it. Below ten Brzycki reads lower — at one rep it returns the weight you lifted, while Epley adds 3.3% to it. Above ten the order flips and the gap widens fast, because Brzycki's denominator is shrinking: 9% apart at 15 reps, 27% at 20. The page opens on their average and shows every formula's answer beside it rather than picking for you, because which one fits you is something only your own heavy singles can settle.
Reps are the accuracy, not the weight
A set of 3 predicts a max well. A set of 15 predicts endurance, and the number it produces is a guess about a lift you have not done. The input stops at 36 reps because Brzycki's formula divides by 37 − reps and becomes meaningless as that approaches zero — at 37 it would divide by zero outright. If you want a usable estimate, test with a weight you can move 3 to 6 times, the last rep close to failure.
Frequently asked questions
How is one-rep max calculated?
From a submaximal set: Epley = weight × (1 + reps/30); Brzycki = weight × 36 ÷ (37 − reps). 100 kg × 5 reps is about 113–117 kg.
How accurate are 1RM estimates?
Good for low reps (roughly under 10) and rougher above that. They’re a training guide — form and fatigue affect a real max.
Which formula should I use?
Near ten reps it does not matter at all — the two formulas meet there. Below ten, Brzycki is the conservative one; above ten, Epley is, and by twenty reps they are 27% apart. Most people take the average, which is what "Estimated 1RM" shows by default, and then correct it against a real heavy single once they have one.
Why does it stop at 36 reps?
Brzycki divides by 37 minus your rep count, so at 37 reps it divides by zero and just below that it produces enormous numbers. 36 is only the last input before that division, not a usable one: at 36 reps Brzycki returns 36 times the weight you lifted. Estimates are worth trusting under about 10 reps; past that, read them as a rough guide.
Is the estimate a weight I should attempt?
No. It is arithmetic on one set, with nothing in it about your form, your fatigue that day, or whether you have a spotter. Treat it as a starting point for programming percentages, not as a target to walk up to the bar and try.
What if I did not take the set to failure?
Set "RPE (how hard the set was)" to how hard it felt — each option spells out the reps you had left, such as "8 — about 2 reps left". Those reps are added to the ones you did before any formula runs, so five reps with two in reserve is estimated as the seven you could have done. It opens on RPE 10, a set to failure.
Can it say what each load is for, or plan my warm-up?
Yes. The “Training loads” table has a “Used for” column naming each load's goal — strength, muscle growth or muscular endurance — with its reps and sets as the NSCA's Essentials of Strength Training and Conditioning assigns them. “Warm-up for a max attempt” lists StrengthLog's warm-up sets, lightest first, each with its weight, reps and rest, ending in the attempt at the estimate. A “Lift” select labels the copied line, and for the deadlift adds that every formula underestimated the deadlift max in LeSuer et al. (1997), so the figure is best read as a floor.
Can it tell me which plates to load, or show the loads in the other unit?
Yes. “Show loads in” turns every load on the page — the estimate, the tables, the copied line and the plates — into kilograms or pounds, converted by the exact pound. “Plates to load” takes a load, the estimate unless you type one, and the bar, and lists the plates for each side from IWF kilo discs or common pound plates; a load the plates cannot make is rounded down to the nearest one they can, and the page says so.