1RM percentages without doing sums on the whiteboard
How to turn «5 × 3 at 80 %» into each athlete's kilos, rounded to your box's plates, and what to do with someone who does not know their max.
Wodmark team Updated 8 Nov 2026 7 min read
Why programme in percentages
Programming strength as percentages of the max (the 1RM, the one-rep max) lets the same session work for someone who squats 60 kg and someone who squats 160. The stimulus is similar for everyone: 80 % weighs the same for each of them relative to what they can lift.
The trouble starts at seven in the morning, with twelve people in front of the whiteboard doing the same multiplication in their heads. Some round up, others load what they had last week, and someone asks out loud what their max was.
The sum, without a calculator
The working weight is the max times the percentage. For a 5 × 3 at 80 %:
| 1RM | Exact 80 % | With a 2.5 kg jump |
|---|---|---|
| 95 kg | 76 kg | 75 kg |
| 122 kg | 97.6 kg | 97.5 kg |
| 140 kg | 112 kg | 110 kg |
A trick that helps at the whiteboard: 10 % is moving the decimal point, and the rest builds from there. 80 % of 140 is 140 minus twice 14. But if every athlete has their max written down, nobody should be doing the sum by hand.
Rounding to your box's plates
The exact number can almost never be loaded. What decides is your smallest plate: with 1.25 kg plates per side, the bar goes up in 2.5 kg steps; with 0.5 kg fractional plates, in 1 kg steps.
In Wodmark you set this once per box (the smallest jump, the unit and the bar weight) and each athlete sees their kilos already rounded, with the plates to put on each side.
Someone who does not know their max
Testing a real 1RM is not always a good idea, above all with new people. You can estimate it from a set of several reps done with good technique. The two most used formulas:
- Epley: 1RM ≈ weight × (1 + reps / 30).
- Brzycki: 1RM ≈ weight × 36 / (37 − reps).
With 100 kg for 5 reps, Epley estimates about 117 kg and Brzycki 112.5 kg. They are estimates: the more reps, the less reliable, and above 10 it is better not to use them. For high percentages, stick with the lower of the two.
When to update the 1RM
A max from six months ago stops being useful: 80 % falls short for someone who has improved and overshoots for someone who has been injured. Three simple rules:
- Review maxes at the end of each strength cycle, not in the middle.
- If someone gets through every set of a high percentage with room to spare, their max has probably gone up.
- A new max is confirmed, not applied on its own. One good afternoon should not change the loads of the coming weeks unless the athlete or the coach decides so.
Wodmark follows that last rule: when a result points to a higher max, the app suggests it and the athlete confirms it. Until then, their percentages are worked out from the max they had.