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One Rep Max Calculator

Estimate one-rep max from a completed set and rep count, then view common training loads as percentages of that estimated max.

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Estimate one-rep max from a working set

Use a completed set and rep count to estimate your one-rep max and common training percentages for strength programming.

95% of 1RM

110.8 kg

90% of 1RM

105 kg

85% of 1RM

99.2 kg

80% of 1RM

93.3 kg

75% of 1RM

87.5 kg

70% of 1RM

81.7 kg

65% of 1RM

75.8 kg

60% of 1RM

70 kg

Results

Estimated 1RM

116.7 kg

Input set

100 kg x 5

Best used for hard sets rather than very easy practice reps.

How to use it

  1. 01Enter the weight you lifted and the number of reps completed.
  2. 02Review the estimated one-rep max.
  3. 03Use the percentage table to set rough training loads for programming.

Result guide

  • Rep-based 1RM estimates are rougher when the rep count gets very high.
  • This page is best for planning, not for replacing safe coaching judgment under a heavy barbell.
  • Estimated max and percentage loads should still be adjusted for technique, fatigue, and exercise type.

Why this page matters

One-rep-max pages are practical because lifters often want a quick training benchmark without testing a true max in the gym.

A calculator is especially helpful when it turns the estimate into usable training loads, not just one headline number.

Frequently asked questions

Is the estimate exact?

No. It is a formula-based approximation that becomes less precise as rep counts rise or lifting conditions change.

Why show percentages of 1RM too?

Because strength programs usually prescribe work as percentages of an estimated maximum rather than using the 1RM figure alone.

Should beginners test a true one-rep max instead?

Often not. Many people use estimates like this to plan training without exposing themselves to unnecessary risk during a true max test.

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