How do you calculate 1 rep max?

The most common formula is Epley (1985): 1RM = weight × (1 + reps/30). For example, lifting 100 kg for 5 reps: 1RM = 100 × (1 + 5/30) = 116.7 kg. Brzycki (1993) formula: 1RM = weight × 36 / (37 − reps). These formulas are most accurate with 1–10 reps; accuracy decreases above 10 reps. The average of multiple formulas gives a more reliable estimate.

What percentage of 1RM should I train at?

Training zones by percentage of 1RM: 90–100%: 1–3 reps — maximal strength (IPF powerlifting competition range). 80–90%: 3–5 reps — strength development. 70–80%: 6–10 reps — hypertrophy (muscle building). 60–70%: 10–15 reps — muscular endurance and hypertrophy. Below 60%: 15+ reps — muscular endurance. These percentages are used by the International Powerlifting Federation (IPF), USAPL, and most national strength federations worldwide.

True 1RM testing carries injury risk, especially for beginners or without proper spotting. Estimating 1RM from submaximal reps (using 5–8 reps at a challenging weight) is safer and nearly as accurate. National strength federations (IPF, USAPL, British Powerlifting, Powerlifting Australia) require competition lifts to be performed with certified spotters and judges for safety.

🏋️ IPF Global Epley Formula Brzycki Formula kg / lbs

One Rep Max (1RM) Calculator

Calculate your one rep maximum from any set. Get a full training percentage table showing what to lift for each training goal — used by powerlifters, strength athletes, and coaches worldwide.

Quick Answer

Epley formula: 1RM = weight × (1 + reps/30). Lifting 80 kg for 8 reps = 80 × 1.267 = 101.3 kg estimated 1RM. For strength: train at 80–90% of 1RM for 3–5 reps. For hypertrophy: 70–80% for 6–12 reps. The International Powerlifting Federation (IPF) uses percentage-based programming; these formulas are universally applied across all countries with no national variation.

Weight lifted (kg)

Reps completed

Most accurate with 1–10 reps. Enter 1 for actual 1RM.

Powerlifting Federation Standards by Country

Country	Federation	Weight Classes & Notes
🌍 International	IPF (International Powerlifting Federation)	Men: 59, 66, 74, 83, 93, 105, 120, 120+ kg. WADA drug-tested. Uses IPF Points for comparison across weight classes.
🇺🇸 USA	USAPL (IPF affiliate)	Drug-tested. Most common federation. Also: USPA (untested), RPS, SPF.
🇬🇧 UK	British Powerlifting (IPF affiliate)	Drug-tested, IPF rules. Also: GPC-GB (untested).
🇨🇦 Canada	CPU (Canadian Powerlifting Union, IPF affiliate)	Drug-tested. Also: CAPO (untested).
🇦🇺 Australia	PA (Powerlifting Australia, IPF affiliate)	Drug-tested, IPF rules. Also: GPC Australia.
🇩🇪 Germany	BVDK (Bundesverband Deutsche Kraftdreikämpfer)	IPF affiliate; drug-tested competitions.
🇯🇵 Japan	JFPA (Japan Powerlifting Federation, IPF affiliate)	Drug-tested; Japan has produced several world-record holders in lighter weight classes.

Training Goals by % of 1RM

Goal	% of 1RM	Rep Range	Used By
Maximal strength	90–100%	1–3 reps	IPF powerlifting, Olympic weightlifting
Strength	80–90%	3–6 reps	Strength athletes, powerlifters
Strength-hypertrophy	70–80%	6–12 reps	Bodybuilding, general gym
Hypertrophy	60–70%	12–20 reps	Bodybuilding, volume training
Muscular endurance	<60%	20+ reps	Functional fitness, rehab

Frequently Asked Questions

Which 1RM formula is most accurate? ▾

For low rep ranges (1–5 reps), all formulas give similar results. For higher reps (8–10+), Brzycki tends to underestimate more than Epley, while Lombardi and O'Conner give higher estimates. No single formula is universally most accurate — using the average of all four gives a more reliable estimate. Most accurate estimation comes from lifts of 3–6 reps with proper technique.

Do powerlifting standards differ by country? ▾

Powerlifting equipment and weight classes are standardized by the International Powerlifting Federation (IPF) globally. Weight classes are the same worldwide (men: 59, 66, 74, 83, 93, 105, 120, 120+ kg). Drug-tested (WADA compliance) vs. untested federations exist in most countries. Country-specific federations include USAPL (US), British Powerlifting (UK), CAPO (Australia), and FAJR (Japan). Performance-enhancing drug rules differ between federations, not countries.