Which 1RM formula is most accurate?

For most lifters and rep ranges (3-8 reps), the Epley formula is the closest to a real tested 1RM. Brzycki is gentler on higher reps (>8) and Lombardi handles very low rep ranges better. When in doubt, use the 'Average' option — it averages all three formulas and tends to be within 2-3% of a real tested max.

How do I use 1RM percentages for training?

60-70% of 1RM = hypertrophy / muscle growth (8-12 reps, 3-4 sets). 75-85% = strength (3-6 reps, 3-5 sets). 90-95% = peak power (1-3 reps). Below 60% is generally warm-up or technique work. Above 95% = testing territory, use sparingly.

Can I use this for bench press, squat, and deadlift?

Yes — all three formulas work for any compound barbell lift. They were originally derived from powerlifting data (primarily squat and bench) so bench press, squat, and deadlift 1RM estimates from a set of 3-8 tend to be very accurate. Exercise selection does not change the math.

How often should I retest my 1RM?

Real (tested) 1RM attempts are taxing — at most every 8-12 weeks. But you can re-estimate using this calculator every 4-6 weeks from a heavy working set (e.g. a top set of 3-5). If your 5RM improves by 10 lb, your estimated 1RM has gone up by roughly 12-13 lb.

Why is my estimated 1RM different from my real tested max?

Formulas predict within about ±5% for most lifters. Differences come from: (1) rep range used — more than 8 reps inflates the estimate, (2) grinding vs. bar-speed style — if your last rep was painfully slow, you were closer to your true max than the formula assumes, (3) individual neural profile — some lifters have a huge gap between 5RM and 1RM, others do not.

One Rep Max Calculator

The One Rep Max (1RM) Calculator estimates the heaviest weight you can lift for a single repetition based on a submaximal set you already performed. Enter the weight you lifted, the number of reps completed at that weight, and pick a formula — Epley, Brzycki, Lombardi, or the average of all three for maximum reliability. You get your estimated 1RM plus a full training-percentage chart (from 60% up to 95%) so you know exactly what weight to load for hypertrophy, strength, and peak power work. This tool is especially useful for the big three powerlifting lifts (bench press, squat, deadlift) but works for any resistance exercise. All three formulas lose accuracy above ~10 reps, so use a heavy set of 3-8 reps for the most reliable estimate.

star 4.9 (524 ratings)

calendar_today Updated: April 2026

New

Your Lift

Weight Lifted

Unit

Reps

Formula

fitness_center

Estimated 1RM

— lb

Enter a lift to estimate

Epley

—

Brzycki

—

Lombardi

—

table_chart

Percentage Training Chart

%1RM	Weight	Typical Reps	Goal

Input Values

Weight Lifted

Reps Performed

Unit

Pounds (lb)

Kilograms (kg)

Formula

Epley

Brzycki

Lombardi

Average of all three

tips_and_updates Tips

• Most accurate in the 3-8 rep range — above 10 reps all formulas drift high
• Warm up properly before any heavy set you plan to convert to a 1RM estimate
• Epley and Brzycki give nearly identical numbers at 5 reps; they diverge at higher reps
• For powerlifting, the 'Average' option smooths out formula bias and is a good default
• Hypertrophy work: 65-75% of 1RM for 8-12 reps, 3-4 sets
• Strength work: 80-90% of 1RM for 3-6 reps, 3-5 sets
• Peak power / max strength: 90-95% of 1RM for 1-3 reps, long rests (3-5 min)
• Recalculate your 1RM every 4-6 weeks — real maxes drift as you train

How to Use This Calculator

Enter weight lifted

Type the weight of your working set in pounds or kilograms.

Enter reps performed

How many clean reps you completed at that weight. Best accuracy is 3-8 reps.

Pick a formula

Epley is the most common; Brzycki is gentler above 8 reps; Lombardi handles low reps well. Use 'Average' for the most neutral estimate.

Read your percentage chart

The chart below shows what to load for hypertrophy (65-75%), strength (80-90%), and peak work (90-95%).

The Formula

All three classical 1RM formulas scale your submaximal set up to a single-rep estimate. Epley (1985) is the most widely used and fits most lifters well. Brzycki (1993) is gentler on higher reps. Lombardi uses a power-law fit. The 'Average' option averages the three to smooth out formula bias. Accuracy is highest in the 3-8 rep range; above 10 reps, estimates diverge sharply.

Epley: w × (1 + reps/30) | Brzycki: w × 36 / (37 - reps) | Lombardi: w × reps^0.10

lightbulb Variables Explained

w Weight lifted (in kg or lb)
reps Number of repetitions performed with that weight
1RM Estimated one rep maximum

tips_and_updates Pro Tips

Most accurate in the 3-8 rep range — above 10 reps all formulas drift high

Warm up properly before any heavy set you plan to convert to a 1RM estimate

Epley and Brzycki give nearly identical numbers at 5 reps; they diverge at higher reps

For powerlifting, the 'Average' option smooths out formula bias and is a good default

Hypertrophy work: 65-75% of 1RM for 8-12 reps, 3-4 sets

Strength work: 80-90% of 1RM for 3-6 reps, 3-5 sets

Peak power / max strength: 90-95% of 1RM for 1-3 reps, long rests (3-5 min)

Recalculate your 1RM every 4-6 weeks — real maxes drift as you train

How the Epley, Brzycki, and Lombardi 1RM formulas work

Epley (1985) uses a linear relationship: 1RM = w × (1 + reps/30). Every additional rep adds about 3.3% of the weight to the max estimate. Brzycki (1993) uses a hyperbolic fit: 1RM = w × 36 / (37 - reps), which caps sensibly as reps climb. Lombardi uses a power-law: 1RM = w × reps^0.10, which is gentle at low rep counts and most accurate for 1-5 reps. All three formulas were fit to real powerlifting data and agree within about 5% for sets of 3-8.

Using 1RM percentages for programming

Most strength programs prescribe work as a percentage of 1RM. General guidelines: 60% = easy technique / speed work, 65-75% = hypertrophy (8-12 reps), 80% = strength endurance (5-6 reps), 85-90% = classic strength (3-5 reps), 92-97% = peak power (singles and doubles). Knowing your current 1RM lets you program intelligently instead of guessing — and this calculator's percentage chart does the math for every band automatically.

Frequently Asked Questions

Related Tools

View all Health & Fitness View all arrow_forward

health_and_safety