Overhead Press 1RM Calculator

By Jack Kyle — Jack Kyle writes about strength training and lifting math — calculators, programming and standards — with a focus on honest numbers and practical guidance.

Strength tools / Overhead Press 1RM

Overhead Press 1RM Calculator

Estimate your overhead press one-rep max — Quick, Consensus, My Curve and RPE.

Enter 2-3 recent sets to failure. We find your curve — more accurate than any generic formula.

6 easy10 max effort

OHP is the strictest of the big four: no leg drive, no back bend beyond a natural lean, bar from shoulders to full lockout. A push-press set (any knee dip) is a different lift and will badly overstate a strict-press 1RM — enter strict-press sets only.

Because OHP loads are small, a 2.5 kg jump is a 4–5% jump at a 50–60 kg press — twice the relative jump of the same plates on a deadlift. That is why this page rounds weights to the nearest 0.5 kg/lb: use 0.5–1.25 kg plates for OHP top sets and progress in 1–2.5 kg steps, not 5 kg jumps.

OHP estimates are most reliable from low-rep sets (1–8) because shoulder and triceps fatigue accumulates fast and bar path drifts on later reps. A 10-rep OHP set that ended with a grind and a layback estimates high — confirm with a heavy triple before attempting a 1RM.

Estimates only — see our Disclaimer

What this calculator does

The overhead press moves the smallest weights of the four main lifts, which makes it the hardest to estimate well. A two-kilogram error is a rounding error on a deadlift and a full jump on a press. This calculator estimates your overhead press one rep max from a rep set, with weights rounded to 0.5 kg/lb, so the numbers it gives you are numbers you can actually load — not a false-precision figure like 61.37 kg that no gym can build.

It is built for lifters who programme press day by percentage: heavy top sets, volume work, and variations that need loads read off one max. It helps when you press a rep personal best and want to know what it implies for next week’s heavy single, or when a 1 kg jump feels like a wall and you want to see where your current sets place you. Enter the weight and the reps from a strict set, take the rounded estimate as a planning number, and let the next heavy session confirm it. The bar decides.

How it works

Enter the weight you pressed and the reps you completed. The calculator applies six published 1RM formulas — Epley, Brzycki, Lombardi, O’Conner, Mayhew, and Lander — to that set and shows a percentage table for training loads.

  • Epley: 1RM = weight × (1 + reps ÷ 30)
  • Brzycki: 1RM = weight × 36 ÷ (37 − reps)
  • Lombardi: 1RM = weight × reps^0.10
  • O’Conner: 1RM = weight × (1 + reps ÷ 40)
  • Mayhew: 1RM = 100 × weight ÷ (52.2 + 41.9 × e^(−0.055 × reps))
  • Lander: 1RM = 100 × weight ÷ (101.3 − 2.67123 × reps)

Rounding. All weights on this calculator are rounded to 0.5 kg/lb. On a press, that rounding is the difference between a load you can build and one you cannot, so the calculator rounds every displayed weight to the nearest half unit rather than showing un-loadable decimals.

Limits to know. The formulas cannot tell a strict press from a push press. A push press uses leg drive, so the same weight and reps describe an easier set and make the estimate read high — enter strict-press sets only. Estimates are most reliable from sets of 1–5 reps and get shakier past 10 reps. For the general case across lifts, use the one rep max calculator.

Calibrate to your own sets (My Median)

Population formulas assume an average lifter. My Median calibrates to you: enter two or three sets you actually lifted, and the calculator takes the Epley estimate from each set and returns the median — the middle value. One outlier set pulls the median far less than it would pull an average. My Median fits no curve and models nothing about your strength curve; it is a median of Epley estimates, and it still needs honest, comparable inputs.

Use strict-press sets only — no leg drive. Enter two or three such sets and the calculator takes the Epley estimate from each and returns the median. The median result is rounded to 0.5 kg/lb like every other result on this calculator. Do not mix strict sets with push-press sets in one My Median calculation.

Frequently asked questions

Why is the overhead press so hard to estimate?

Because the weights are small and the jumps between them are large in percentage terms. A 2.5 kg jump on a 60 kg press is over 4% — the same jump on a 200 kg deadlift is barely over 1%. Small absolute errors therefore look large on the press, which is why this calculator rounds to 0.5 kg/lb and why low-rep inputs matter more here than anywhere.

Strict press vs push press — which numbers go in?

Strict-press numbers only. A push press adds leg drive, so it lets you handle more weight for the same reps and makes a strict-press estimate read high. If you train both, log them as separate lifts and do not mix the inputs.

Why does the calculator round to 0.5 kg/lb?

Because most gyms cannot load finer than that. Fractional plates exist, but a result like 61.37 kg cannot be built from standard plates, so it pretends at a precision the gym cannot deliver. Rounding to the nearest 0.5 kg/lb keeps every displayed weight loadable with ordinary plates.

My press stalls while other lifts grow — is the estimate wrong?

Not necessarily. The press grows slowly because the muscles involved are small and the loads are light, so progress shows up in smaller steps than on the squat or deadlift. If the estimate stays flat across several blocks while your logged sets improve, re-check that the input sets are strict, low-rep, and done to the same standard.

How do I use the percentage table for press day?

Read your top-set percentage off the table, then work back down through warm-ups and working sets. The plate calculator turns each percentage into a per-side plate list — useful on press day, when the small plates matter — and the warm-up calculator maps the jumps to your top set. To compare the number against other lifters, use the strength standards calculator.