How do I calculate my one-rep max?

Enter the weight you lifted and how many reps you completed. The calculator estimates your 1RM using established formulas such as Epley, Brzycki and Lombardi, then shows a median estimate and range.

One Rep Max Calculator

Estimate your one-rep max

Q: How accurate is a 1RM calculator?

A 1RM calculator provides an estimate, not a guarantee. Lower-rep sets usually give more useful estimates than high-rep sets because fatigue and individual endurance vary more as reps increase.

Q: Is estimated 1RM better than testing a max?

Many lifters use estimated 1RM for programming without frequently attempting true maximal singles. An estimate from a recent working set is often more practical than max testing.

Enter a weight and rep count to estimate your 1RM and useful training percentages.

Weight lifted

Repetitions

Unit

kg lb

Estimated 1RM

Primary estimate

Estimated 1RM 99.5 kg

Estimated range: 98.5–101.5 kg

Useful estimate

Moderate-rep sets are still useful for estimating 1RM, but individual endurance varies.

Estimated rep maxes

Rep max	Estimated weight
1RM	99.5 kg

Percentage of 1RM

% of 1RM	Weight
100%	99.5 kg

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What is a one-rep max?

A one-rep max (1RM) is the maximum load you can lift for one successful repetition with appropriate technique. It is a common reference point for strength programming, even when you rarely test a true single.

How is estimated 1RM calculated?

This calculator estimates 1RM from a completed set using three established formulas:

Epley: weight × (1 + reps ÷ 30)
Brzycki: weight ÷ (1.0278 − 0.0278 × reps)
Lombardi: weight × reps^0.10

The primary estimate is the median of the formula outputs. The range shows the lowest and highest estimate. If you enter a completed single, the result is the weight you lifted.

How accurate is a 1RM calculator?

Any 1RM calculator provides an estimate, not a guarantee. Lower-rep sets usually give more useful estimates than high-rep sets. Individual endurance, exercise selection, technique and fatigue all affect how closely an estimate matches a true max.

Should I test my real 1RM?

Many lifters programme from estimated 1RM without frequently attempting true maximal singles. An estimate from a recent working set is often more practical than max testing, especially when you are training consistently and want to avoid unnecessary fatigue or risk.

Worked example

For 80 kg × 8 reps, the formulas estimate roughly 98.5–101.5 kg, with a median estimate of about 99.5 kg. Rep-max and percentage tables are derived from that primary estimate using the inverse Brzycki relationship.

Turn one set into your next session

OVED uses your real workout history to track progress and help plan what you should do next.