How accurate are 1RM calculators?

1RM calculators are generally accurate within 5-10% when used with rep ranges under 10. The accuracy depends on factors like training experience, muscle fiber composition, and the specific formula used. Our calculator uses 7 different formulas to give you the most comprehensive estimate.

Which 1RM formula is most accurate?

The Epley formula is most widely used and accurate for most people, especially with rep ranges of 2-10. However, different formulas work better for different individuals. Brzycki tends to be conservative, while Lombardi works well for powerlifters. Our calculator shows all 7 formulas so you can compare.

Can I use this for any exercise?

Yes, you can use 1RM calculators for any compound exercise like bench press, squat, deadlift, overhead press, and rows. The formulas are based on general strength principles that apply across exercises, though they're most accurate for compound movements.

What rep range should I use for the most accurate calculation?

For best accuracy, use rep ranges between 2-10 reps. The sweet spot is 3-8 reps where most formulas perform optimally. Avoid using very high rep ranges (15+) as the formulas become less reliable due to muscular endurance factors.

How often should I recalculate my 1RM?

Recalculate your 1RM every 4-6 weeks or whenever you notice significant strength gains. For beginners, monthly calculations work well. Advanced lifters might recalculate every 6-8 weeks. Always use recent max effort sets for the most accurate results.

What percentage of 1RM is 5 reps?

A set of 5 reps to failure typically corresponds to approximately 87% of 1RM. This is an average across rep-to-failure validation studies; individual variance ranges from 83-90% depending on training experience and muscle fiber composition. For programming, 5 reps at 80-85% is the common prescription for sub-maximal strength work.

What percentage of 1RM is 8 reps?

A set of 8 reps to failure typically corresponds to approximately 80% of 1RM. Programming-wise, 8 reps at 70-77% is the standard prescription for hypertrophy work with 2-3 reps in reserve. At 80%+, the set will be at or near failure for most lifters.

What percentage of 1RM is 10 reps?

A set of 10 reps to failure corresponds to approximately 75% of 1RM. For productive hypertrophy programming without taking sets to failure, prescribe 10 reps at 65-72%, which leaves 1-3 reps in reserve and produces high training volume.

How accurate is the 1RM percentage chart?

The standard rep-to-percentage chart is accurate to within ±5% for trained lifters. Individual variation comes from muscle fiber composition (fast-twitch dominant lifters have shallower drop-off) and training emphasis (lifters who train predominantly low-rep have a higher rep-to-1RM relationship). For programming, the chart is reliable; for true 1RM testing, use the 7-formula calculator instead.

Are these percentages the same for all exercises?

No — these percentages are most accurate for compound barbell lifts (squat, bench, deadlift, OHP, row). For Olympic lifts (snatch, clean & jerk), rep drop-off is steeper because technical complexity limits sets. For isolation movements (curls, lateral raises), the chart underestimates rep capacity at sub-maximal loads.

Printable reference

1RM Percentage Chart

The standard rep-to-percentage chart for strength programming. Use it to set working weights, design percentage-based programs, and convert between rep counts and %1RM.

Reps to %1RM

Reps	% of 1RM	Training Zone
1 rep	100%	Max Strength
2 reps	95%	Max Strength
3 reps	92%	Max Strength
4 reps	90%	Strength
5 reps	87%	Strength
6 reps	85%	Strength
7 reps	83%	Strength
8 reps	80%	Hypertrophy
9 reps	77%	Hypertrophy
10 reps	75%	Hypertrophy
11 reps	72%	Hypertrophy
12 reps	70%	Hypertrophy
13 reps	68%	Endurance
15 reps	65%	Endurance
18 reps	62%	Endurance
20 reps	60%	Endurance

Percentages reflect a set taken to failure (RPE 10). For programming with reps-in-reserve, deduct 3-5% per RIR. See the RPE calculator for full RPE-to-percentage tables.

Percentage table for common 1RMs

Direct lookup table for popular 1RM values. Find your max in the leftmost column, read across to find the corresponding training weight at each percentage.

1RM	95%	90%	85%	80%	75%	70%	65%	60%
135 lb	130	120	115	110	100	95	90	80
185 lb	175	165	155	150	140	130	120	110
225 lb	215	205	190	180	170	160	145	135
275 lb	260	250	235	220	205	195	180	165
315 lb	300	285	270	250	235	220	205	190
365 lb	345	330	310	290	275	255	235	220
405 lb	385	365	345	325	305	285	265	245
455 lb	430	410	385	365	340	320	295	275