1RM calculator.

1RM = weight × 36 / (37 − reps) up to 10 reps, weight × (1 + reps / 30) from 10 to 15, and at most 5% more past 15. A single is the weight itself. Use a challenging lower-repetition set when available; high-rep estimates depend more on individual repetition endurance.

How accurate is a 1RM calculator?

Accuracy varies by exercise, technique, and effort. A challenging lower-repetition set generally offers a more useful comparison than a high-repetition set. Past 15 reps the estimate barely rises; that limits extrapolation but does not guarantee accuracy.

Which formula does this use?

Brzycki up to 10 reps, Epley from 10 to 15, then at most +5% past 15 reps. A single returns the weight itself.

Should I test my true 1RM?

You do not need a true maximum to use this tool. A recent challenging set gives an estimate for planning. Actual maximal testing is a different task that needs appropriate preparation, equipment, and supervision; the estimate is not a substitute for a measured result.

How do I use percentages of my 1RM?

Use the percentage specified by your program, then adjust for the intended repetitions and effort. The table converts your estimate into loads from 100% to 50%. Percentages do not guarantee a particular rep count.

Enter the total weight you lifted and the number of completed reps. For a barbell exercise, include the bar and both sides of plates. Use a recent, challenging set of the exact exercise you want to estimate. A paused bench press and a touch-and-go bench press are different performances; a calculator cannot adjust for the pause.

An estimated one-rep max, or e1RM, converts a multiple-repetition set into a rough single-repetition equivalent. It helps compare sets such as 185 lb for five reps and 190 lb for four reps without requiring a maximal attempt. It does not establish that you can lift the displayed weight today.

For example, 185 × 5 gives 185 × 36 / 32, or approximately 208 lb. A set of 190 × 4 gives approximately 207 lb. Those two sets suggest similar estimated strength even though one used a heavier weight. Small differences can reflect ordinary variation in effort and technique rather than a meaningful gain or loss.

A bench press of 135 lb for eight reps estimates 171 lb. A squat of 225 lb for five estimates 262.5 lb, displayed as 263. A deadlift of 315 lb for three estimates 346.5 lb, displayed as 347. These are examples of the formula, not strength standards or recommended attempts. Your training history and execution still matter.

For a single repetition, this tool returns the weight itself: 225 × 1 returns 225. Above 12 repetitions, it uses 12 in the calculation. That means 100 × 12 and 100 × 20 both return 140 lb. The cap limits extrapolation; it does not make a high-repetition set as informative as a heavier set. Use a lower-repetition set when you have one available.

Keep the weight convention consistent for dumbbells. If you enter one 40 lb dumbbell, the result describes one dumbbell. If you enter the combined 80 lb, it describes the combined load. Do not compare a per-hand number against a combined-load record. Machine stack numbers should also stay tied to the same machine and setup.

Multiply the estimated maximum by the percentage in your program. If your estimate is 216 lb and the program calls for 75%, the arithmetic gives 162 lb. Then choose a load you can actually build, such as 160 lb, and check that it fits the prescribed effort and repetitions. The plate calculator shows the plates for your selected total.

A percentage is a starting point, not a promise about repetitions. Exercise choice, fatigue, rest periods, and individual repetition endurance affect how a load feels. A meta-regression of repetitions at percentages of 1RM found variation in the relationship, including differences between exercises. Avoid treating a percentage chart as an exact rep limit.

If the prescribed set becomes a grind much earlier than expected, reduce the load. If you finish with substantially more capacity than the program intended, record that before increasing next time. A useful estimate supports decisions; it should never force you to ignore the set you are actually performing.

Compare the same lift, range of motion, equipment, and approximate effort across sessions. A set stopped with several reps remaining will usually understate your capacity compared with a near-limit set. Do not invent extra repetitions to correct the estimate; record the completed reps and note the effort separately.

Look for a trend across several workouts. One unusually strong or tired session should not rewrite your entire program. More reps at the same weight, the same reps with more weight, or cleaner technique at the same load can all be worthwhile progress. The displayed e1RM captures only the first two directly.

For your next session, use the warm-up calculator to rehearse the planned lift. To compare the six yardstick lifts in SET, open the strength level calculator. An estimated maximum and a strength level answer different questions: one estimates a load, while the other places performance on SET’s bodyweight-adjusted scale.