Wathan Formula 1RM Calculator

The Wathan formula is an exponential model published in the National Strength and Conditioning Association journal.

100w ÷ (48.8 + 53.8 × e^(−0.075r)) — The Wathan formula is an exponential model published in the National Strength and Conditioning Association journal.

5 reps
One Rep Max
5 reps @ 225lb
253
lb
Wathan formula
Estimated One Rep Max
5@225lb
253lb
Using the Wathan formula
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Big Four Strength Levels

Strength levels for a 200lb male, age 30 lifting 253lb in each lift type · enter your details.

Rep Max Projections

Wathan algorithm

RepsWeight (lb)
1RM253lb
2RM246lb
3RM239lb
4RM232lb
5RM(current)225lb
6RM218lb
7RM211lb
8RM204lb
9RM197lb
10RM190lb
20RM119lb

Percentage Calculator

Based on 253lb estimated max

IntensityWeight (lb)
100%253lb
95%240lb
90%228lb
85%215lb
80%202lb
75%190lb
70%177lb
65%164lb
60%152lb
55%139lb
50%127lb
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