1RM Calculator – Calculate Your One Rep Max for Any Lift

Find your one-rep max without maxing out. Enter the weight and reps you lifted to calculate your estimated 1RM and set smarter strength training goals.

Weight Lifted

Unit

Repetitions Performed

For best accuracy, use 3-10 reps

How to Use This 1RM Calculator

Enter Your Lift Data

Input the weight you lifted and the number of reps you completed with good form.

Calculate Your 1RM

Click "Calculate 1RM" to see your estimated one-rep max across multiple formulas.

Use Your Results

Apply your 1RM to set training percentages for strength, hypertrophy, or endurance work.

1RM Formula Comparison

Formula	Best For	Characteristics
Epley	Higher reps (8+)	Most commonly used formula. Simple calculation that works well across rep ranges.
Brzycki	Lower reps (3-7)	Gives conservative estimates. More accurate when testing with heavier weights and fewer reps.
Lander	Moderate rep ranges	Balanced approach. Works well for mid-range rep testing between 5-10 reps.
Lombardi	Higher rep ranges	Tends to overestimate for very high reps. Uses exponential calculation method.

Rep Max Percentage Chart

Use this chart to plan training loads based on your 1RM. Each rep range corresponds to a percentage of your one-rep max.

Reps	% of 1RM	Training Focus
1	100%	Maximum strength
2	95%	Maximum strength
3	93%	Strength
4	90%	Strength
5	87%	Strength
6	85%	Strength / Power
7	83%	Strength / Hypertrophy
8	80%	Hypertrophy
9	77%	Hypertrophy
10	75%	Hypertrophy
11	72%	Hypertrophy / Endurance
12	70%	Muscular endurance

Safe Rep Ranges for Testing

Why You Shouldn't Test 1RM Directly

Testing your actual one-rep max carries real risks. Heavy single attempts put significant stress on your joints, connective tissue, and central nervous system. The injury risk goes up when you're fatigued or your form breaks down under maximal load. Most lifters don't need to test true 1RM regularly.

Best Rep Ranges for Testing

3-5 Reps (Strength Focus)

Best for strength athletes. Heavy enough to give accurate 1RM estimates while keeping form solid. Lower CNS fatigue than true max attempts.

8-10 Reps (Hypertrophy Focus)

Better for bodybuilding or general fitness. Less joint stress, safer for solo training. Form stays cleaner through the set.

When to Use Submaximal Testing vs Actual 1RM

Use submaximal testing (3-10 reps) for most training cycles. It's safer, easier to recover from, and gives you the data you need. Save actual 1RM attempts for competition prep or specific testing phases—maybe 2-3 times per year max. Even then, work up gradually and stop if form breaks down.

Frequently Asked Questions

How accurate are 1RM calculators?

1RM calculators give estimates, not exact numbers. They're usually within 5-10% of your actual 1RM when you test in the 3-10 rep range. Accuracy drops outside that range. Use them as a guide, not a guarantee.

What's the best rep range for testing 1RM?

3-5 reps works best for strength-focused lifts. 8-10 reps is better for hypertrophy work or if you're training alone. Both ranges give solid estimates without the risks of max testing.

Should I test my 1RM directly?

Most of the time, no. Submaximal testing is safer and easier to recover from. Only test true 1RM if you're preparing for competition or have a specific reason. Even then, limit it to a few times per year.

Do different formulas give different results?

Yes. Each formula uses different math, so results vary—especially at higher rep counts. That's why this calculator shows multiple formulas. The average usually gives a reasonable estimate.

Can I use this for any exercise?

This works best for compound lifts like squat, bench press, deadlift, and overhead press. It's less accurate for isolation exercises or movements where fatigue hits before the target muscles do (like grip on deadlifts).

Other Free Tools

Search tools