Estimated one-rep max (e1RM)
The estimated one-rep max (e1RM) is the heaviest weight you could probably lift once, calculated from a set you actually did. It lets you compare a set of 5 at 120 kg with a set of 3 at 130 kg on one scale.
Formula
Sparlift's default is the Epley formula, adjusted for reps in reserve (RIR):
e1RM = weight × (1 + (reps + RIR) / 30)
Adding RIR treats a set stopped short of failure as if you had done the reps you had left. With no RIR logged, Sparlift assumes 0, which gives the plain Epley formula.
Brzycki and plain Epley are also available. The formula is a user setting, and every stored value records which formula produced it.
Parameters
| Parameter | Value | Source |
|---|---|---|
| Divisor | 30 | Epley formula |
| RIR when not logged | 0 | Convention |
| Maximum reps used | 12 | Estimates get unreliable on long sets |
Test vectors
These cases are shared between the engine's tests and this page, so the two cannot disagree.
| Weight | Reps | RIR | Expected e1RM |
|---|---|---|---|
| 100 kg | 5 | 0 | 116.7 kg |
| 100 kg | 5 | 2 | 123.3 kg |
| 150 kg | 3 | 1 | 170.0 kg |
Limits
e1RM formulas are population averages. They drift for very high rep sets and differ between people and between lifts. Use the trend over weeks rather than any single value.