1RM RPE Calculator: Find Your True Max Without Testing It
Calculate your estimated 1RM instantly using RPE. Stop grinding through unnecessary max tests and use our 1RM RPE calculator to find your daily readiness.
1RM Calculator
Stop guessing your strength. Accurately estimate your one rep max and generate exact percentage breakdowns for your working sets.
RTS Method
Science-Backed
Instant Results
Plate Rounding
How it works
Follow the exact steps to get your result instantly and privately.
Step 1
Step 1: Enter weight lifted
Input the exact amount of weight you lifted during your toughest set.
The Math: Predicting Maximal Strength
Our 1RM calculator utilizes established mathematical formulas to estimate your maximal strength. The most popular equations are the Epley formula and the Brzycki formula. The Epley formula is often preferred for higher rep ranges, while the Brzycki formula is highly accurate for fewer than 10 reps. Both formulas extrapolate the exponential relationship between weight and reps to failure.
RPE Intensity Meter
InteractiveTap or hover any level below
Calculation Formulas
Epley Formula: 1RM = Weight × (1 + (0.0333 × Reps))
Brzycki Formula: 1RM = Weight × (36 / (37 - Reps))Worked Example
If you squatted 225 lbs for 5 reps, the Epley formula calculation is 225 × (1 + (0.0333 × 5)). This evaluates to 225 × 1.1665, giving an estimated 1RM of 262 lbs.
Worked examples
| Scenario | Calculation | Result |
|---|---|---|
| Lifter A — Bench Press | 225 lbs × 5 reps | e1RM ≈ 262.5 lbs |
| Lifter B — Squat | 315 lbs × 3 reps | e1RM ≈ 346.5 lbs |
| Lifter C — Deadlift | 405 lbs × 8 reps | e1RM ≈ 512.9 lbs |
Conversion reference
| Percentage of 1RM | Expected Reps |
|---|---|
| 100% | 1 Rep |
| 95% | 2 Reps |
| 93% | 3 Reps |
| 90% | 4 Reps |
| 87% | 5 Reps |
| 85% | 6 Reps |
| 80% | 8 Reps |
| 75% | 10 Reps |
| 70% | 12 Reps |
| 65% | 15 Reps |
DID YOU KNOW?
Quick facts
Estimates are most accurate when you use a set of 1 to 5 repetitions. The higher the reps, the less accurate the 1RM prediction becomes.
A true 1RM test is physically exhausting and can disrupt training for days. Using a calculator allows you to gauge progress without maxing out.
Different lifts have different rep-max profiles. You might be able to do more reps at 85% of your squat max compared to your deadlift max.
From the blog
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Frequently asked questions
When calculating from 5 reps or fewer, it is generally very accurate (within 5% of your true max). Accuracy drops significantly if you calculate from sets of 10+ reps because muscular endurance factors begin to skew the results.
No. Beginners are better off using a 1RM calculator. Testing a true 1RM requires excellent technique under maximum load. Beginners have not ingrained the motor patterns enough to do this safely.
The Epley and Brzycki formulas are the industry standard. Epley tends to be slightly more accurate for sets over 5 reps, while Brzycki is very precise for low rep sets. Our calculator averages these or provides the most relevant output based on your rep input.
You should recalculate at the end of a training block or whenever you hit a new rep PR (personal record). If your 5-rep max goes up, your estimated 1RM has gone up.