Which 1RM formula is most accurate?

Research shows Epley and Brzycki perform best for 1–6 rep ranges. For higher reps (8–12+), accuracy degrades across all formulas. The consensus estimate (average of multiple formulas) tends to be more robust than any single formula. For powerlifting meets, using 90-95% of your calculated 1RM as your opening attempt is standard practice.

How many reps should I use for the most accurate estimate?

2–5 rep sets give the most accurate 1RM estimates. Beyond 8–10 reps, fatigue and cardiovascular endurance begin to influence performance, reducing formula accuracy. For best results, use a weight you fail or could fail on rep 4–6.

What is a training max and why is it different from my 1RM?

A training max (TM) is typically 85–90% of your estimated 1RM and is used as the reference number for percentage calculations in programs like 5/3/1. Using a training max rather than true 1RM provides a buffer that keeps weekly training weights submaximal, reducing injury risk and allowing progression.

Should I actually test my 1RM?

Actual 1RM testing is recommended only for experienced lifters with strong technique, adequate warm-up, and a spotter (for barbell lifts). Beginners and intermediates are better served by estimated 1RM from submaximal sets. When in doubt, underestimate — starting a program with weights slightly too light is always safer and more productive than starting too heavy.

❤️Health

What Is Your True Maximum Lift?

What is your maximum lift?

What This Does

Your one-rep maximum (1RM) is the heaviest weight you can lift for a single repetition with proper form. It's the foundational number in strength training programming — almost all percentage-based training programs (5/3/1, conjugate, linear periodization) derive their working weights as percentages of your 1RM. Knowing your 1RM accurately makes the difference between a program that challenges you appropriately and one that's too easy or too hard. The problem is that actually testing your 1RM carries injury risk, especially for beginners and intermediate lifters. That's where predictive formulas come in. Using a submaximal weight (a weight you can lift 2–10 times) combined with your rep count, multiple validated formulas estimate your 1RM within ±5% accuracy for most lifters. The most commonly cited formulas are Epley (best for lower rep ranges), Brzycki (reliable 2–10 reps), and Lombardi (used by powerlifting coaches). No single formula is universally best — this calculator shows you results from all three and gives you a consensus estimate. It then generates a full training zone breakdown: 50% (warm-up), 60% (hypertrophy endurance), 70% (moderate hypertrophy), 75% (5x5 range), 80% (strength), 85% (heavy strength), 90% (near-maximal), 95% (competition prep), and 100% (1RM attempt).

When Should You Use This?

→Setting up a percentage-based strength training program (5/3/1, conjugate, etc.)
→Estimating your true 1RM without the injury risk of an actual max attempt
→Calculating working weights across all training zones and percentages
→Tracking strength progress by comparing 1RM estimates over time
→Preparing for a powerlifting meet or strength test

Example Scenario

Derek can squat 275 lbs for 5 reps. Using the Epley formula: estimated 1RM = 275 × (1 + 5/30) = 321 lbs. Brzycki gives 327 lbs. Lombardi gives 318 lbs. Consensus estimate: 322 lbs. For his 5/3/1 program, his training max is 90% = 290 lbs. Week 1 working sets: 65% (209 lbs), 75% (242 lbs), 85% (274 lbs). The calculator produces all of these in one calculation.

One Rep Max Calculator

4 Formulas · Training Zones · Standards · 5/3/1 Program

Results update in real time as you adjust any input.

Weight Unit

Sex

Lift Type

Weight Lifted (lbs)

lbs

Reps Completed

Most accurate: 1–5 reps

Bodyweight (lbs)

lbs

About This Calculator

This one rep max calculator estimates your 1RM using four established formulas — Epley, Brzycki, Lombardi, and Mayhew — and displays the consensus average as your primary result. It supports both lbs and kg, four major lifts with strength standards (Squat, Bench Press, Deadlift, Overhead Press), and bodyweight-based relative strength classification. Results update in real time as you adjust any input. The Training Max (90% of 1RM) is calculated automatically for programming use.

The Zones tab renders a horizontal bar chart of all 9 training zones (50–100% of 1RM) colour-coded from sky blue (warm-up) to dark red (1RM), with a reference line at your max and gram labels on each bar. The Standards tab provides a radar chart of your progress toward Beginner/Intermediate/Advanced/Elite thresholds across all four levels, plus a bar chart comparing strength standard thresholds to your current 1RM with a reference line at your max. The Sensitivity tab plots a line chart of 1RM estimates across rep counts 1–12, with your current set highlighted.

The 5/3/1 program tab generates all four weeks of Wendler's 5/3/1 with precise plate-friendly weights rounded to the nearest 2.5 lbs/kg. A strength score (0–100) reflects both strength level and set quality (lower rep sets score higher). Accuracy flags appear automatically when rep counts exceed 6 or formula variance exceeds 8%. Export to PDF generates a complete report with the full zone reference table and key insights.

Results are estimates only and do not constitute medical advice. Consult a qualified healthcare professional before making health decisions.