Calculate your estimated max lift (1-rep max) for any exercise. Enter the weight and number of repetitions performed to estimate your one-rep max (1RM).
Safety note: This calculator provides an estimate (not a guaranteed safe or exact max). Do not attempt a true 1-rep max based only on this result. Use proper warm-ups, technique, and a spotter/safeties when appropriate, and stop if you feel pain, dizziness, or unusual symptoms. If you’re new to lifting or have an injury/medical condition, get guidance from a qualified professional.
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1RM Calculator
This calculator estimates a one-rep max (1RM) using common 1RM prediction equations. All 1RM predictions are approximations, and they tend to be most reliable when based on lower-rep sets (roughly 1–10 reps, up to ~12).
- 1 Rep - 100% max lift
- 2 Reps - 95% max lift
- 3 reps - 93% max lift
- 4 reps - 90% max lift
- 5 reps - 87% max lift
- 6 reps - 85% max lift
- 7 reps - 83% max lift
- 8 reps - 80% max lift
- 9 reps - 77% max lift
- 10 reps - 75% max lift
- 11 reps - 73% max lift
- 12 reps - 70% max lift
As reps increase, estimates can become less reliable—especially beyond about 10–12 reps.
One Rep Max Calculator
Why would you need to know your max lift of any given exercise?
First, almost all lifting programs are based on your max lifts. Using your max lift numbers is used as a gauge to determine how much workload you can handle. Of course, this is only an estimation, but it's still an essential first step in setting up a weight lifting program.

Another good use of this calculator is to estimate where you are at for powerlifting competitions. More often than not, you don't want to max out every lift every single week. This puts enormous strain on your body and leads to injury. Instead, most people go for reps or 3-5 for strength. When leading up to competition, powerlifters definitely don't want to max out because they might get hurt. Instead, you can use this calculator to gauge where you are at and plan your competition lifts.
For more information on lifting, visit our bench press calculator.
For more related calculators, visit our health & fitness calculators.
Source:
https://www.sciencedirect.com/science/article/pii/S0169814112001126