One Rep Max
Overhead Press 1RM Calculator
Estimate your overhead press one rep max. Enter the weight you pressed and the number of reps for results from both the Epley and Brzycki formulas, plus a training percentage table for your programme.
How the overhead press 1RM calculator works
This calculator estimates your one rep max using two widely-used formulas. You enter the weight you lifted and the number of reps you completed, and the calculator works backwards to predict the heaviest single rep you could perform.
The Epley Formula
Developed by Boyd Epley, this is one of the most commonly used 1RM prediction equations. Tends to produce slightly higher estimates at higher rep ranges (above 10 reps).
1RM = weight × (1 + reps ÷ 30)The Brzycki Formula
Created by Matt Brzycki, this formula is slightly more conservative and is often preferred for lower rep ranges. Becomes invalid at 37 or more reps.
1RM = weight × (36 ÷ (37 − reps))Which formula is more accurate?
Neither is universally better. For rep ranges of 1–6 both produce very similar results. Above 10 reps, Epley tends to overestimate slightly. This calculator shows both so you can compare.
Using the percentage table
The training percentage table shows what weight to use for different intensities based on your estimated 1RM. Most strength programmes prescribe working sets between 70–85% of 1RM, while hypertrophy work typically falls in the 60–75% range.
Frequently asked questions
What is a good overhead press 1RM?
For men, 0.75x bodyweight is intermediate. A bodyweight overhead press is advanced and a significant milestone. For women, 0.5x bodyweight is a solid intermediate benchmark.
Standing vs seated overhead press — which should I use?
Standing press is the standard for 1RM comparison as it engages more stabiliser muscles. Seated press removes leg drive and core demands, typically yielding a lower number. Be consistent with your variation.
Why is the overhead press so hard to progress?
The shoulders are smaller muscle groups than the legs or back, so progress is naturally slower. Adding 1–2.5kg per month is realistic for intermediate lifters. Microplates can help with smaller increments.
Can I use push press reps to estimate strict press 1RM?
No. Push press uses leg drive and will significantly overestimate your strict press. Only use strict overhead press reps with this calculator for an accurate estimate.
How do I avoid shoulder injury when pressing heavy?
Warm up thoroughly with band pull-aparts and light sets. Keep your core braced, ribs down, and avoid excessive back lean. Stop the set immediately if you feel any sharp pain in your shoulders.