FRAMIR · TOOLS
1RM Calculator – Estimate Your One-Rep Max
Enter the weight and completed reps from a single set. Get an estimated one-rep max and a simple percentage-based load table.
Use a regular set completed without assistance. Weight: 0.1–1,000 kg. Repetitions: 1–20 whole reps. A decimal point or comma is accepted.
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Estimated 1RM
More than 10 reps: treat this estimate with extra caution. Longer sets also reflect muscular endurance.
| Percentage of 1RM | Rounded load |
|---|---|
| 100 % | — |
| 95 % | — |
| 90 % | — |
| 85 % | — |
| 80 % | — |
| 75 % | — |
| 70 % | — |
| 65 % | — |
| 60 % | — |
The estimate is displayed to one decimal place. Loads use the unrounded estimate and are rounded to the nearest 2.5 kg, matching FRAMIR’s default for percentage-based loads. Halfway values round up. Adjust for your equipment; very light loads may round to 0 kg.
What is a one-rep max?
Your one-rep max, or 1RM, is the heaviest weight you can lift once in a specific exercise. An estimated 1RM uses a completed set to approximate that weight. It is a reference for that particular lift, not a single score for your overall strength.
How to use the 1RM calculator
Enter the load and the number of reps you actually completed. For a barbell lift, include the bar and plates. Keep your weight convention consistent, including when using dumbbells. A set with plenty of reps left in reserve can underestimate your maximum: the calculator cannot know how many more reps you could have done.
How estimated 1RM is calculated
FRAMIR uses the Epley principle: estimated 1RM = weight × (1 + repetitions / 30). For exactly one rep, it returns the weight itself, just like the app. For example, 100 kg for 8 reps gives 126.7 kg. This is an estimate, not a recommendation to attempt that weight.
How accurate is an estimated 1RM?
Accuracy depends on the exercise, technique and how demanding the set was. Shorter sets are generally a more useful starting point than long sets. Research on bench press and leg press found better predictions from 5RM than from 10RM or 20RM tests. That does not validate an individual result for you or every exercise. Treat estimates from more than 10 reps with particular caution.
Using 1RM in your strength training
Use the estimate as a reference when a program calls for a percentage of 1RM, or compare similar sets over time. Keep the exercise, range of motion and execution as consistent as possible. The table only calculates percentages: it does not prescribe reps or tell you which load is appropriate on a particular day.
Estimated 1RM versus a tested max
A tested max records a weight you have actually lifted once. An estimate projects a possible maximum from multiple reps. You do not need a max attempt to keep track of training. If you choose to test, plan your warm-up, equipment and appropriate assistance. An estimate is not a guarantee that you can complete the lift.
Read the guide: Progressive Overload – How to Keep Making Progress in Strength Training →
Track your strength and progress with FRAMIR
Log weight, reps and workout history in FRAMIR to follow your strength over time. The app also calculates estimated 1RM for logged sets. Actual single-rep lifts remain distinct from estimates.