🏋️ 1-Rep Max (1RM) Calculator

Calculate your true maximum strength and get a full training percentage breakdown for any lift.

Select Lift

🏋️ Bench Press

🦵 Squat

💀 Deadlift

🔝 Overhead Press

🔄 Barbell Row

⚙️ Other

Weight Lifted

lbs

kg

Weight

Reps Completed

Calculate My 1RM →

Bench Press 1RM — lbs Averaged across Epley, Brzycki & Lombardi formulas

Training Percentage Breakdown

← Recalculate

Quick How-To Guide

1

Select Your Movement & Unit Choose the specific exercise you performed and toggle between lbs or kg.

2

Enter Weight and Reps Input a recent weight you successfully lifted and the exact number of clean repetitions completed (best results occur between 1 and 10 reps).

3

Analyze Your Breakdown Click Calculate to instantly view your estimated absolute maximum and unlock tailored percentage targets for your strength, hypertrophy, or endurance training blocks.

💡 Pro Tip For the highest accuracy, use data from an "all-out" set where your form remained flawless. Testing with sets of more than 10 repetitions makes mathematical 1RM predictions less accurate due to muscular fatigue variations.

What Is Your True Strength? How to Calculate Your 1-Rep Max

Your one-rep max — the maximum weight you can lift for a single repetition — is the gold standard for measuring strength. But testing it directly is risky and unnecessary. This calculator estimates your 1RM from a set you actually did, so you can program smarter without rolling the dice on a max lift.

Why Your 1-Rep Max Matters

If you have ever followed a strength program, you have seen percentages like "work up to 85% of your 1RM." These are meaningless without knowing your actual maximum. Your 1RM is also the most objective measure of strength progress — body weight fluctuates, measurements can be unreliable, but if your squat went from a 185-pound 1RM to 225 pounds over three months, that is unambiguous progress.

💡 Companion Feature

The PR Tracker is the natural companion to this calculator — it logs your 1RM records over time and shows the delta from each previous best, so you can see the trajectory your training is producing rather than just the single number you have today.

How the Formulas Work

Three major formulas are used to estimate 1RM from submaximal sets. This calculator averages all three for a more reliable result.

The Epley formula — the most commonly used — multiplies your working weight by one plus the number of reps divided by 30. The Brzycki formula is considered more accurate for very low-rep sets (2 to 6 reps). The Lombardi formula uses a power function and produces slightly different results for higher-rep sets. Averaging all three consistently outperforms any individual formula across a wide range of training scenarios.

The Best Rep Range for Accurate Estimates

The most accurate 1RM estimates come from sets of 2 to 8 reps. As rep counts go higher, accuracy drops — fatigue, breathing, and technical breakdown introduce variability the formulas cannot fully account for.

Using Your 1RM to Set Training Weights

The percentage breakdown table shows you what to lift for different rep ranges and goals. For maximal strength development, most programs use 85 to 95 percent of 1RM for sets of 1 to 5 reps. For hypertrophy, the sweet spot is 65 to 80 percent for sets of 8 to 12 reps. If you want to put these percentages to work inside a fully structured program, the 12-Week Strength Planner uses your 1RM as the foundation for a periodized training block that builds systematically toward new maxes.

When to Retest Your 1RM

Your 1RM changes as you get stronger, so update it periodically. A practical approach is to retest every 4 to 8 weeks using a new working set. Many lifters track these retest numbers over time in the Strength Volume Tracker alongside their weekly volume data — which makes it easy to see whether volume increases are translating into actual strength gains.