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Protocolv0.17.0 BETA
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Training tool

One-rep max calculator

Estimate your 1RM from a recent set, then turn that estimate into a practical training-max reference. Useful for structured lifting blocks. Not a promise of a tested max.

Best for

For lifters using structured strength or hypertrophy programs who need a planning number without max testing every week.

Estimate from a recent set

Lower-rep sets usually make better inputs.

Use the load you actually lifted with the technique you want to compare over time.

This public calculator accepts 1-12 reps and caps RPE-adjusted reps at 12.

Estimated result

Enter a recent set.

The output will show formula spread, RPE/RIR adjustment, and a conservative training max.

No black box

Formula transparency

Protocol shows the formula spread instead of pretending there is one perfect estimate. Epley uses weight x (1 + reps / 30). Brzycki uses weight x 36 / (37 - reps).

The displayed Protocol estimate averages those two outputs when both are available. RPE is handled as a simple reps-in-reserve adjustment: RPE 10 means 0 reps left, RPE 9 means about 1 rep left, and so on.

Treat the result as a planning number. If your program uses a training max, keep it conservative and update it from repeatable sets, not one unusually good day.

Use the next calculator

Set a training maxOnce you have an e1RM, turn it into a lower planning number before percentage work.Choose an RPE loadIf today's set is effort-based, use the e1RM as the starting point for RPE planning.Load the barBefore lifting the target, translate the number into plates and check the remainder.

Formula and assumptions

  • Epley: weight x (1 + reps / 30).
  • Brzycki: weight x 36 / (37 - reps).
  • Protocol estimate: average the available formula outputs, then adjust for RPE by adding estimated reps in reserve.

Use it well

  • Use a recent set with consistent technique, preferably lower reps, as the input.
  • Compare formula outputs instead of treating one number as truth.
  • Use the training max as a conservative anchor for planned percentages.
  • Retest with the same movement standard so the trend means something.

Keep it honest

Caveats

  • Estimated 1RM is a planning reference, not a tested max.
  • Higher-rep sets, inconsistent tempo, form changes, fatigue, and exercise selection can distort estimates.
  • Max testing needs appropriate setup, spotting, and experience.

References

Sources