Free One-Rep Max Calculator 🏋️

Weight Lifted

Repetitions (1–10)

Formula

Epley (default, most common)

Enter a weight and reps above to see your estimated 1RM and training percentages instantly.

What is Free One-Rep Max Calculator 🏋️?

🏋️ A One-Rep Max (1RM) is the maximum weight you can lift for a single repetition of an exercise with proper form. It is the universal currency of strength sports and a foundational metric for structured training programming. Why does your 1RM matter? Training loads in powerlifting, weightlifting, and strength-focused programming are expressed as percentages of 1RM. A program that prescribes "3 sets at 80%" means nothing unless you know your 1RM. Testing your true maximum is risky and unnecessary — instead, lift a submaximal weight for multiple reps and use a validated formula to estimate it safely. 📐 The Three Formulas: Epley (1985) — default, most widely used: 1RM = Weight × (1 + Reps ÷ 30) Brzycki (1993) — more accurate for lower rep ranges (1–5): 1RM = Weight × (36 ÷ (37 − Reps)) Lander (1985) — good for intermediate lifters: 1RM = (100 × Weight) ÷ (101.3 − 2.67123 × Reps) Example — bench pressing 225 lbs for 5 reps: Epley: 225 × (1 + 5/30) = 225 × 1.167 = 262.5 lbs Brzycki: 225 × (36 ÷ 32) = 225 × 1.125 = 253.1 lbs Lander: (100 × 225) ÷ (101.3 − 13.36) = 22,500 ÷ 87.94 = 255.8 lbs 🏆 Training Percentage Zones: 95%: Near-maximal strength (1–2 reps) 85–90%: Heavy strength work (2–3 reps) 75–80%: Hypertrophy + strength (4–6 reps) 65–70%: Moderate hypertrophy (8–12 reps) 50–60%: Technique, volume, active recovery Note: All formulas assume reps are performed to or near muscular failure. Accuracy decreases above 10 reps, which is why this calculator limits input to 1–10 reps.

How to Use This Tool

1
Enter the Weight you lifted in the input field. Click the unit toggle to switch between lbs and kg — the value converts automatically.
2
Select the number of Repetitions you performed (1–10) using the number pad. Accuracy is highest for 1–5 rep sets.
3
Choose a Formula: Epley is the standard default. Brzycki is preferred for 1–5 rep sets. Lander is a good alternative for intermediate lifters. Results update live as you switch.
4
Your estimated 1RM appears in the hero card. The Training Percentage Table below shows target weights for 50%–95% of your max.
5
Use the table to program your training blocks: find the percentage your program prescribes and read across to the exact target weight.

Real-World Use Cases

A Powerlifter Programming After a Heavy Bench Session

You successfully bench pressed 225 lbs for 5 reps. Enter 225 lbs × 5 reps using the Epley formula — your estimated 1RM is 262.5 lbs. Your next training block calls for 80% work sets. The percentage table immediately shows 80% = 210 lbs. No mental math. You load 210 lbs and know exactly where you stand relative to your ceiling.

An Everyday Gym-Goer Tracking Squat Progress Safely

You've been squatting for 6 months and want to gauge progress without risking injury by attempting a true max. You squat 185 lbs for a solid 8 reps. The calculator estimates your 1RM at ~240 lbs (Epley). Three months earlier you could only do 135 lbs for 8 reps (~175 lbs estimated 1RM). That's a 37% increase in estimated max strength — measurable progress without ever touching a dangerous load.

Structuring a Full Training Block Using Percentages

Your deadlift 1RM is estimated at 315 lbs. The percentage table gives you your entire 6-week mesocycle: Week 1 at 65% = 205 lbs, Week 2 at 70% = 220 lbs, Week 3 at 75% = 236 lbs, Week 4 at 80% = 252 lbs, Week 5 peak at 85% = 268 lbs, deload at 60% = 189 lbs. Your full program is structured in under 30 seconds.

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