One Rep Max Calculator
Benched 225 for 5 — what could you lift for a single? Estimate your 1RM from any recent set with four published formulas, then get the percentage chart coaches actually program from, without ever maxing out in the gym.
Estimated one-rep max (average of 4 formulas)
258.3 lb
Epley
262.5 lb
Brzycki
253.1 lb
Lombardi
264.3 lb
O'Conner
253.1 lb
Training percentages (from 258 lb)
95%
245 lb
~2 reps
90%
232 lb
~4 reps
85%
220 lb
~6 reps
80%
207 lb
~8 reps
75%
194 lb
~10 reps
70%
181 lb
~12 reps
65%
168 lb
speed work
60%
155 lb
warm-ups
These are estimates only — formulas typically land within ~5% for sets of 2–6 reps and drift further apart beyond that. Don't attempt an actual 1RM test without a spotter and proper warm-up. Educational use only.
How 1RM Formulas Work
Every formula converts “weight × reps” into an equivalent single lift, just with different curves. Take 225 lb for 5 reps: Epley gives 225 × (1 + 5/30) = 262.5 lb, Brzycki gives 225 × 36/32 = 253.1 lb, Lombardi gives 225 × 50.1= 264.3 lb, and O'Conner gives 225 × 1.125 = 253.1 lb — an average of about 258 lb. The ~11 lb spread is the honest uncertainty, which is why this calculator highlights the average rather than any single formula.
The four formulas (w = weight, r = reps)
Epley w × (1 + r/30) 262.5 lb @ 225×5
Brzycki w × 36/(37 − r) 253.1 lb
Lombardi w × r^0.10 264.3 lb
O'Conner w × (1 + 0.025r) 253.1 lb
Training: strength 80–90% · hypertrophy 65–80%
speed/technique 60–70% of 1RMFrequently Asked Questions
How much should I be able to bench for my bodyweight?
Common strength standards put a novice male around 0.75× bodyweight for one rep, intermediate around 1× bodyweight, and advanced around 1.5×; women's standards run roughly 0.5×/0.75×/1× for the same levels. These are benchmarks from lifting populations, not requirements — training age, limb length, and bodyweight class all shift them. Use a recent multi-rep set in the calculator above to see where your estimated 1RM lands.
Which one rep max formula is most accurate?
For sets of 2–6 reps, Epley and Brzycki agree within a few pounds and both track tested maxes well; the spread widens with rep count. At 225 lb × 5 the four formulas here range from 253 to 264 lb — about 4%. Averaging them, as this calculator does, smooths out each formula's individual bias.
How many reps should I use to estimate my 1RM?
A heavy set of 3–6 reps gives the tightest estimate. Past about 10 reps the formulas drift apart badly because high-rep sets are limited by muscular endurance as much as raw strength — a 12-rep set can overestimate or underestimate a true max by 10% or more depending on your fiber type and training history.
What percentage of my 1RM should I lift for muscle growth?
Hypertrophy work typically lives at 65–80% of 1RM for sets of 6–12 reps, while pure strength work sits at 80–90%+ for sets of 1–5. With an estimated 1RM of 258 lb, that's roughly 168–207 lb for growth-focused sets. Research shows lighter loads also build muscle if sets approach failure, but the 65–80% band is the most time-efficient zone.