Liftquill
1RM calculator
Enter a weight and how many reps you did. You get your estimated one-rep max and the weight to use for every percentage.
Percentage of your 1RM
| % of 1RM | Weight | Reps (approx.) |
|---|
Your 1RM for every exercise, automatically
Liftquill estimates your 1RM from every set you log and shows how it grows. Free app, no subscription.
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Estimated max for each rep count
| Reps | Weight |
|---|
How the 1RM calculator works
Your one-rep max (1RM) is the heaviest weight you can lift once with good form. The calculator estimates it from a lighter set with the Epley formula: 1RM = weight × (1 + reps ÷ 30). 100 kg for 5 reps gives about 117 kg. It is the same formula the Liftquill app uses.
How to use your 1RM
Most programs give weights as a percentage of 1RM. Around 85% is a heavy set of 5, 75% a set of about 10 and 65% lighter technique work. The table rounds to the nearest 2.5 kg (5 lb) so you can load the bar.
Questions
Is it safe to test my real 1RM?
You rarely need to. An estimate from a set of 3–8 reps is close enough for planning and much easier on the body. If you do test, warm up well and use a spotter or safety bars.
Which 1RM formula is best?
Epley and Brzycki give almost the same result between 2 and 10 reps, usually within a few percent. Above 12 reps all formulas get less reliable, since endurance starts to matter more than strength.
How often should I update my 1RM?
Every few weeks, or whenever you set a new best. In Liftquill it updates by itself from every set you log.