Tools / 1RM Calculator
1RM Calculator
Estimate your one-rep max from any working set. Uses three validated formulas so you can see the consensus estimate.
Example calculation
You lift 100 kg for 5 reps on the barbell bench press. Here is what each formula gives you:
- Epley: 100 × (1 + 5 ÷ 30) = 117 kg
- Brzycki: 100 ÷ (1.0278 − 0.0278 × 5) = 116 kg
- Lombardi: 100 × 50.1 = 115 kg
- Consensus (average): 116 kg
To set your 80% training weight from a 116 kg 1RM: 116 × 0.80 = 93 kg. Use this for hypertrophy work (8–12 rep sets). For strength work at 85%: 116 × 0.85 = 99 kg.
Track your 1RM over time in SteelRep
SteelRep logs every set and tracks your estimated 1RM automatically — so you can see your strength progress across every lift.
How the formulas work
Epley formula
1RM = weight × (1 + reps / 30)
The most widely used formula. Slightly overestimates at higher reps but is reliable for sets of 2–10 reps.
Brzycki formula
1RM = weight × (36 / (37 - reps))
Often considered more accurate for sets under 10 reps. Produces undefined results at 37+ reps, which is beyond any practical strength application.
Lombardi formula
1RM = weight × reps^0.10
A power-law formula that tends to produce slightly lower estimates than Epley. Useful as a conservative lower bound.