One-rep max calculator

A one-rep max (1RM) estimate lets you plan squat, bench, deadlift, or press percentages without testing a true max every week. Enter a weight you lifted for 1–12 solid reps; FreeNutri shows Epley and Brzycki estimates plus a chart from 95% down to 60% of the average. Free, no signup, and built for training math—not ego loading.

Epley and Brzycki in practice

Epley estimates 1RM as weight × (1 + reps/30). Brzycki uses weight × 36/(37 − reps). For a single clean rep, both equal the weight on the bar. At five reps with 100 kg, Epley lands near 116.7 kg and Brzycki near 112.5 kg; we also show the average so you can pick a middle ground for programming.

Accuracy falls as reps climb or form breaks down. Sets of three to eight clean reps usually estimate better than a fifteen-rep grind. Rest long enough that the set represents strength, not pure fatigue. If the last reps turn into a different exercise, the formulas will invent a fantasy max.

Using the percentage chart

Many programs prescribe work as a percent of 1RM: heavy singles near 90%+, volume work around 70–80%, and technique sets lower. The chart applies those percentages to the average estimate so you can sketch warm-ups and working sets quickly. Round to the nearest plate your gym actually has.

Recalculate when the working weight for a given rep range jumps meaningfully—after a deload, a new peak, or a long layoff. An outdated 1RM makes “80%” days secretly max-effort days. Keep a simple log of the set you used for the estimate (lift, weight, reps, date) so future you trusts the number.

Safety and progression before max math

Estimated maxes are not permission to miss a lift with poor bracing. Warm up, keep a spotter or safety pins on barbell work, and stop if joints complain. Beginners often progress faster by adding small loads to comfortable sets than by chasing theoretical 1RMs every session.

Nutrition supports the chart: protein for repair, carbohydrates around hard lower-body days, and overall calories from a realistic TDEE. Strength stalls that look like “weak programming” are often sleep and under-eating. Pair this calculator with FreeNutri’s calorie and protein tools when recovery feels off.

Which lifts fit these formulas?

The classic equations were popularized for compound barbell lifts. Machines, kettlebells, and odd objects still benefit from relative loading, but treat the output as a planning aid. Unilateral work and Olympic lifts have different fatigue profiles—use conservative numbers there.

If Epley and Brzycki disagree by a large margin, your rep range may be high or the set quality uneven. Retest with fewer reps and cleaner form. Consistency of method matters more than which formula is “correct” in a textbook sense.

Keep training sustainable

Use 1RM math to organize weeks, not to turn every Tuesday into a meet. Cycle intensity, leave reps in reserve on most sets, and schedule easier days after heavy lower-body work. The free calculator is here so the arithmetic never blocks you from training.

Educational only—not medical advice. People rehabbing injuries or managing blood pressure should clear intense loading with a clinician or qualified coach. FreeNutri does not replace coaching cues or in-person spotting.