1RM Calculator — what's your max?
Enter a set you actually did. We estimate your max load (one-rep max) and, above all, give you how much to load for each rep count. No need to go test heavy.
Most reliable between 1 and 10 reps. Beyond 12, the estimate becomes indicative only.
Or just ask Vance
The calculator estimates from a single number. Vance knows your real sets.
How do you estimate your 1RM?
This calculator converts a real set into a theoretical max load. Rather than relying on a single equation, it averages four reference formulas, which smooths out their differences:
- Epley: 1RM = load × (1 + reps ÷ 30)
- Brzycki: 1RM = load × 36 ÷ (37 − reps)
- Lander: 1RM = 100 × load ÷ (101.3 − 2.67 × reps)
- Lombardi: 1RM = load × reps0.10
The result is reliable between 1 and 10 reps. Beyond 12, muscular endurance starts to outweigh pure strength and the estimate becomes indicative only: a set of 20 reps depends as much on your cardio as on your max strength.
How much should you load for 5, 8 or 12 reps?
That's the real question when you train: not "what's my max", but "how much do I put on the bar today". The chart above starts from your estimated 1RM and gives you the matching load for each rep count, from a heavy single (1 rep ≈ 100%) all the way to long sets (20 reps ≈ 60%).
In practice: you find your set for the day (for example "8 reps"), you read the load next to it, and you load it. No more guessing or doing math between sets. That's exactly what most calculators almost never give you — and yet it's the most useful part.
How do you turn your 1RM into a program (5×5)?
Most programs are driven as a percentage of your 1RM. A few benchmarks:
- Strength (2 to 6 reps): 85 to 95% of 1RM. To build maximal strength.
- Hypertrophy (8 to 12 reps): 70 to 80%. The sweet spot for putting on muscle.
- Strength endurance (15 reps and up): 60 to 65%.
A classic 5×5 runs around 80-85% of your 1RM. The key isn't the exact number: it's progressive overload. As soon as you finish all your sets cleanly, you add 2.5 kg (or one rep) the next session. It's that steady climb, week after week, that drives progress — not testing your max every month.
Estimate rather than test (and why that's often better)
Going for a true 1RM is risky (technique that degrades under maximal load), draining for the nervous system, and frankly pointless 95% of the time. An estimate from a set of 3 to 6 reps is precise enough to program your loads, without the risk.
The classic self-taught lifter's doubt — "am I loading enough? is my program any good?" — isn't solved by testing your max, but by following a consistent progression. Estimate, load, progress, re-estimate every 4-6 weeks.
If you insist on testing your true max, do it safely
A 1RM test needs preparation: a full warm-up, progressive loading (heavier and heavier sets with fewer and fewer reps), a spotter on bench press and squat, and safety pins set. Never test your max cold, on a tired day, or on an exercise you don't master technically. When in doubt, the estimate remains the smarter choice.
Frequently asked questions
What is a 1RM (one-rep max)?
Your 1RM is the heaviest load you can lift a single time on a given exercise (bench press, squat, deadlift…). It's the reference point for calibrating your loads: most programs are based on a percentage of your 1RM.
How do you estimate your 1RM without testing it?
You take a set you actually did (for example 80 kg × 5) and a formula converts it into a theoretical max. This calculator averages four reference formulas (Epley, Brzycki, Lander, Lombardi). No need to go heavy and risk getting hurt.
Are the formulas reliable?
They're accurate between 1 and 10 reps (error margin ~5%). Beyond 12 reps, the estimate gets shaky: endurance starts to outweigh pure strength. Stick to sets of 3 to 8 reps for the most accurate calculation.
Which formula should you use for more than 10 reps?
None is truly reliable beyond 12 reps. If you do long sets, do a heavier set (3 to 6 reps) once in a while just to re-estimate your 1RM cleanly. That's why we average several formulas: it smooths out the differences.
How do you turn your 1RM into a 5×5 program?
A 5×5 generally runs around 80-85% of your 1RM. With a 1RM estimated at 100 kg, you start your 5×5 around 80 kg, then add 2.5 kg as soon as you finish your 5×5 cleanly. The rep chart above gives you the load for each rep count directly.
Is my 1RM the same on every exercise?
No. Each movement has its own 1RM: your squat max has nothing to do with your curl max. Estimate a 1RM for each main lift (squat, bench press, deadlift, overhead press) from a set done on THAT exercise.
How often should you re-estimate your 1RM?
Every 4 to 6 weeks is enough. Your working loads climb session after session; redo the calculation from your best recent set to recalibrate your percentages. No need to do it every week.
Should you actually test your true 1RM in the gym?
Rarely, and never without experience or a spotter. To make progress, you don't need to know your max to the kilo: you need to know what load to aim for next session. That's exactly what this calculator does — and what Vance does, from your real sets.
What are the strength / hypertrophy / endurance zones for?
They tell you which load to use based on your goal: strength ≈ 85-95% of 1RM (2-6 reps), hypertrophy ≈ 70-80% (8-12 reps), endurance ≈ 60-65% (15 reps and up). The rep chart gives you the exact load for each case.
How do I know if my estimated 1RM is accurate?
Your estimate is reliable if three conditions are met: you started from a set of 3 to 8 reps (not 15), the set was close to failure (1-2 reps in reserve, not 5), and the result is consistent with your usual loads. If you estimated your bench max at 120 kg while you barely grind out 80 kg for 5 reps, one of those conditions is missing. When in doubt, do a real heavy set of 5 reps and recalculate.
Should I estimate or test my true 1RM?
Estimate, in the vast majority of cases. Testing a true max is risky (technique breaks down under maximal load), draining for the nervous system, and frankly pointless 95% of the time. An estimate from a set of 3 to 6 reps is precise enough to program your loads, without the risk. Only test if you compete in a strength sport — and even then, only with a full warm-up, progressive loading and a spotter.