# Estimate a one-rep max

GET query params (same names as `/api/v0/one-rep-maxes`):

- `weight` (required)
- `reps` (required)
- `formula` (default: epley)
- `unit` (default: kg)
- `rpe` or `rir` (not both)

`100 × 5 @ RPE 8` is treated as `100 × 7 @ 10`, then the formula runs. That leftover-rep rule is not the Helms % chart.

These tools estimate or convert numbers. They are not a training plan.

Live UI: [/calculator/one-rep-max](/calculator/one-rep-max)