One-Rep Max Percentage Chart

Find your one-rep max down the left edge and read across for the load at each training percentage. Figures are rounded to the nearest half kilogram, which is finer than most gyms can actually load — round to whatever your plates allow, and prefer rounding down when the programme calls for many sets.

The reps column is the number a trained lifter can typically complete at that load, taken close to but not beyond failure. It is a guide rather than a rule: rep capacity at a given percentage varies considerably between people and between lifts.

The general pattern is that heavier loads for fewer reps develop maximal strength and neural efficiency, while lighter loads for more reps accumulate the volume that drives muscle growth. The overlap is large — hypertrophy occurs across a wide range of loads provided sets are taken near failure — so the choice of percentage is more about managing fatigue and practising the lift than about unlocking a specific adaptation.

A 1RM is usually estimated rather than tested, and there are four widely used formulas for doing it. The table below inverts each one: instead of predicting a max from a set, it shows what percentage of your max each formula thinks a given rep count represents.

Three findings come out of that table, and all three have practical consequences.

• The formulas agree best in the middle. The tightest agreement is at 7 reps, where the four fall within 2.3 percentage points of each other. That is the range to test from if you want a reliable estimate — a set of six to eight reps taken near failure.
• They fall apart at high reps. By 15 reps the spread reaches 15.2 percentage points. On a 100 kg max that is a 15 kg disagreement about the same set. Estimating a max from a set of 15 is not a calculation so much as a guess.
• Two of them have hard limits. Brzycki divides by 37 minus reps, so it returns nonsense as reps approach 37 and is undefined at exactly 37. Lander goes negative past about 38 reps. Lombardi, being a power function, keeps producing plausible-looking numbers well past the point where it is meaningful — which makes it the most misleading of the four at high reps rather than the most robust.

This is why the one-rep max calculator averages all four rather than picking one. It also explains the rounding in the first table: when the input carries several percentage points of uncertainty, precision to the half kilogram is decoration.

One cross-check between the two tables on this page is worth making. Compare the average column above with the conventional percentage-to-reps table in the previous section. Through the heavy rows they line up: the formula average across five to six reps runs from 86.9 down to 84.6 percent, and the conventional table calls that range 85. From seven reps upwards the conventional figure drifts just below the formula span — 80 percent against a formula average of 80.2 to 82.3 for seven to eight reps, and 70 against 71.9 to 73.9 for eleven to twelve. The gap never exceeds about two percentage points, and where the two differ it is always in the same direction: the conventional chart prescribes marginally less weight than the formulas imply, which is the safer direction for a programme to err in.

Percentage charts are built on population averages, and individual rep capacity at a given percentage varies enough to matter.

• Rep capacity is lift-specific. Most lifters manage more reps at a given percentage on the squat and deadlift than on the bench press, because more muscle mass is involved and the range of motion is longer. Applying one chart to every lift will overshoot on some and undershoot on others.
• Training history changes the curve. Lifters with more experience at low reps tend to express a higher percentage of their max for a single, while those who train mostly in higher rep ranges do better at 70 to 80 percent than the chart predicts.
• Estimates assume a set near failure. If you stop three reps short, every formula underestimates your max substantially. Reps in reserve is the variable the formulas cannot see, and it is the largest single source of error.
• Deadlifts and isolation work fit worst. Formulas were validated mostly on bench press and squat. Deadlift rep capacity drops off faster than the equations predict for many lifters, and small isolation movements do not follow the pattern at all.

The practical method is to log an actual set — weight and reps taken near failure — recalculate every few weeks, and treat the estimate as a starting load rather than a verdict. If your programme is written around percentages, using a slightly conservative 1RM costs almost nothing and prevents the whole block from running too heavy.