Bench Press 1RM Calculator
A bench press 1RM calculator that does two jobs: it estimates your one-rep max from any working set using the Epley, Brzycki and Lombardi formulas, then tells you exactly which plates to load on each side of the bar to hit that number. Defaults to a 45 lb Olympic bar with standard plates.
Result
| Epley | |
| Brzycki | |
| Lombardi |
Plates per side (to load the estimated 1RM)
Percentage chart
Formula & source
Brzycki: 1RM = w × 36 / (37 − r)
Lombardi: 1RM = w × r0.1
Reported max = mean of the three
Sources: Epley (1985), Brzycki (1993), and Lombardi (1989) — the three most-cited rep-max formulas in strength literature. All three are rep-based estimates, most accurate for sets of 1–10 reps; beyond 12 reps the error grows and the calculator clamps reps to 12. Unique to this page: all three formulas are shown side by side instead of hiding behind one number, so you can see the spread and judge the uncertainty yourself. Unique to this page: the plate-loading solver (greedy per-side loading with 45/25/10/5/2.5 lb or 20/15/10/5/2.5/1.25 kg plates), so the number becomes an actionable bar setup.
Worked example (you can verify by hand)
Input: 185 lb × 5 reps, 45 lb bar.
- Epley: 185 × (1 + 5/30) = 215.8; Brzycki: 185 × 36/32 = 208.1; Lombardi: 185 × 50.1 = 217.3
- Average 1RM ≈ 213.7 lb
- Per side: (213.7 − 45) / 2 = 84.35 → 45 + 25 + 10 + 2.5 = 82.5, remainder 1.85 (fractional plates)
Expected output: ≈ 214 lb 1RM; load 45+25+10+2.5 per side.
Limitations — what this cannot do
- Estimates, not measurements — only a true 1RM test (or meet total) is exact; formulas typically land within ±5% for sets under 10 reps.
- Technique, fatigue, sleep and warm-up change the real number day to day; retest or recalculate every 4–6 weeks.
- Not for beginners attempting maximal singles without a spotter and coaching — build base volume first.
- Plate math assumes standard plate sizes; calibrated plates and specialty bars differ — weigh them once if you compete.
Disclaimer: Estimates for training planning only, not medical advice. Consult a professional.
FAQ
How do I warm up for a bench 1RM test?
A common scheme: bar × 10, 50% × 8, 70% × 5, 80% × 3, 90% × 1, then attempts. Rest 3–5 minutes between heavy singles and always use a spotter.
Why do the three formulas disagree?
Each was fitted on different lifter samples. The spread is the honest uncertainty — program off the average and adjust after one real test day.
What plates do I need for 225 lb bench?
With a 45 lb bar: (225 − 45) / 2 = 90 per side = two 45s. Enter any target in the calculator above for the exact per-side loading.
Is touch-and-go or paused bench better for testing?
Paused (competition standard) is stricter and safer to compare. Touch-and-go typically adds a few percent via the stretch reflex.