RPE to 1RM Calculator
Enter the weight, the reps, and how hard the set felt on the RPE scale. The calculator converts it to a percentage of your max with the standard RPE chart and gives you an estimated one-rep max in kg or lb, plus target loads for every RPE.
| RPE | % of 1RM | Weight |
|---|---|---|
| 10 | 86.3% | 107 kg |
| 9.5 | 85.0% | 105 kg |
| 9 | 83.7% | 103.5 kg |
| 8.5 | 82.4% | 102 kg |
| 8 | 80.8% | 100 kg |
| 7.5 | 79.7% | 98.5 kg |
| 7 | 78.6% | 97.5 kg |
| 6.5 | 77.4% | 96 kg |
| 6 | 76.5% | 94.5 kg |
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Log RPE with every set
1RM.fit records weight, reps and RPE for each set and keeps your estimated 1RM for every lift current automatically.
What Are RPE and RIR?
RPE stands for rate of perceived exertion. In lifting, it is a 1 to 10 score for how hard a set was, anchored to how many more reps you could have done. The version strength coaches use comes from powerlifter and coach Mike Tuchscherer of Reactive Training Systems, who tied each number to reps left in the tank instead of a vague feeling of effort.
RIR, reps in reserve, is the same idea counted from the other end. RPE 10 means 0 RIR: no more reps were possible. RPE 9 means 1 rep left, RPE 8 means 2, RPE 7 means 3. Half points cover the in-between, so RPE 8.5 means you definitely had 1 more rep and maybe 2.
Below RPE 6 the scale stops being useful for strength work, because very few people can tell 5 reps in reserve from 6. That is why the chart and this calculator run from RPE 6 to 10.
How the RPE Chart Converts Effort to a Percentage
The RPE chart gives the percentage of your 1RM that matches any combination of reps and RPE. The calculator looks up that percentage and divides the weight you lifted by it: estimated 1RM = weight ÷ chart percentage.
The chart is really one curve read diagonally. A set of 2 at RPE 10 and a single at RPE 9 both sit at 95.5%, because both mean you had exactly 2 reps of capacity at that load. Each extra rep, or each extra rep in reserve, moves you down the curve by about 3 to 4.5 percentage points near the top and closer to 2 points further down.
Worked example in kg: you bench 100 kg for 5 reps and rate it RPE 8, meaning 2 reps left. The chart puts 5 reps at RPE 8 at 80.8%. Divide 100 by 0.808 and your estimated 1RM is 123.8 kg, which the calculator rounds to 124 kg (about 273 lb). If next week calls for a triple at RPE 8, the chart says 86.3%, so 123.8 × 0.863 = 106.8 kg. Load 107.5 kg or 105 kg depending on your plates and how warm-ups move.
RPE vs Rep-Based 1RM Formulas
- Rep formulas assume failure. Epley and Brzycki treat every set as if you could not do one more rep. Most training sets stop short of that, so a set of 5 with 2 left in the tank undershoots your max. The same 100 kg × 5 at RPE 8 gives 116.7 kg with Epley but 123.8 kg from the RPE chart.
- RPE counts the reps you left behind. Because the chart knows you had 2 reps left, it treats your set of 5 like a 7 rep max. Run 100 kg × 7 through Epley and you get 123.3 kg, nearly identical to the chart.
- RPE moves with the day. A rep formula gives the same answer on a great day and a terrible one. An RPE estimate follows how the bar actually felt, which is why coaches use it to adjust load inside a session.
- Rep formulas need no judgment. If you cannot rate effort reliably yet, a set taken to technical failure plus a standard formula is the more honest input. The section on trusting RPE below covers who falls where.
RPE Chart: RPE and Reps to % of 1RM
Read across for reps and down for RPE. The number in each cell is the percentage of your 1RM that set represents. Divide the weight lifted by that percentage to estimate your max, or multiply your max by it to pick a load for a prescribed set.
| RPE (RIR) | 1 rep | 2 reps | 3 reps | 4 reps | 5 reps | 6 reps | 7 reps | 8 reps | 9 reps | 10 reps | 11 reps | 12 reps |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 10 (0) | 100.0% | 95.5% | 92.2% | 89.2% | 86.3% | 83.7% | 80.8% | 78.6% | 76.5% | 74.4% | 72.3% | 70.3% |
| 9.5 (0.5) | 97.8% | 93.9% | 90.7% | 87.8% | 85.0% | 82.4% | 79.7% | 77.4% | 75.5% | 73.3% | 71.3% | 69.4% |
| 9 (1) | 95.5% | 92.2% | 89.2% | 86.3% | 83.7% | 80.8% | 78.6% | 76.5% | 74.4% | 72.3% | 70.3% | 68.5% |
| 8.5 (1.5) | 93.9% | 90.7% | 87.8% | 85.0% | 82.4% | 79.7% | 77.4% | 75.5% | 73.3% | 71.3% | 69.4% | 67.6% |
| 8 (2) | 92.2% | 89.2% | 86.3% | 83.7% | 80.8% | 78.6% | 76.5% | 74.4% | 72.3% | 70.3% | 68.5% | 66.7% |
| 7.5 (2.5) | 90.7% | 87.8% | 85.0% | 82.4% | 79.7% | 77.4% | 75.5% | 73.3% | 71.3% | 69.4% | 67.6% | 65.8% |
| 7 (3) | 89.2% | 86.3% | 83.7% | 80.8% | 78.6% | 76.5% | 74.4% | 72.3% | 70.3% | 68.5% | 66.7% | 64.9% |
| 6.5 (3.5) | 87.8% | 85.0% | 82.4% | 79.7% | 77.4% | 75.5% | 73.3% | 71.3% | 69.4% | 67.6% | 65.8% | 64.0% |
| 6 (4) | 86.3% | 83.7% | 80.8% | 78.6% | 76.5% | 74.4% | 72.3% | 70.3% | 68.5% | 66.7% | 64.9% | 63.1% |
When to Trust RPE, and When Not To
RPE works best for lifters with at least a year or two of consistent training who have taken sets close to failure often enough to know what 1 or 2 reps left really feels like. Research on trained lifters shows their reps-in-reserve guesses on hard sets are usually within about 1 rep, which keeps an RPE-based estimate within a few percent.
Beginners are a different story. Newer lifters tend to underrate how much they have left, often by 3 reps or more on a set they would call RPE 8. Feed that into the chart and the estimated max comes out too low. If you are in your first year, lean on a rep-based calculator using sets near failure, and practice RPE on the side: call your number before the last rep, then occasionally check it by doing extra reps with a spotter.
Accuracy also drops at the low end of the scale and at high reps. An RPE 9 triple is a far better input than an RPE 6.5 set of 10, because the closer you are to failure, the easier it is to judge what is left.
How to Run RPE-Based Programming
Most RPE programs prescribe a top set by reps and RPE, then base the rest of the work on it. A typical day reads: squat 1 × 3 @ RPE 8, then 3 × 5 at 85% of that top set load. You work up until a triple feels like 2 reps left, and that weight sets the rest of the session. On a great day the top set is heavier, on a rough day it is lighter, and the training stress stays where your coach intended.
Use the estimated 1RM from each top set as a running record. If your e1RM from an RPE 8 triple climbs from 160 kg to 165 kg over a block, you got stronger without ever testing a max. If it drops for two or three sessions in a row, that is a signal to pull back volume or take a deload.
Keep most work in the RPE 7 to 9 range. RPE 10 sets are for testing, not building, and anything under 7 is usually warm-up territory for strength goals. Log the RPE with every set, because a few months of your own data will show whether your 8s are honest.
RPE Calculator FAQ
What is an RPE chart?
An RPE chart lists the percentage of your one-rep max that matches each combination of reps and RPE. For example, 5 reps at RPE 8 sits at 80.8% of your 1RM. Coaches use it both ways: to estimate your max from a set, and to choose a load for a prescribed set.
How do you calculate 1RM from RPE?
Find the percentage for your reps and RPE on the chart, then divide the weight by it. 100 kg for 5 reps at RPE 8 is 80.8%, so 100 ÷ 0.808 = about 124 kg. The calculator on this page does that lookup for you in kg or lb.
What does RPE 8 mean in lifting?
RPE 8 means you stopped the set with about 2 good reps left in the tank. It is the most common target for strength work because it is heavy enough to drive progress while leaving enough margin to keep technique clean and recovery manageable.
Is RPE or a rep max formula more accurate for 1RM?
For experienced lifters, RPE is usually more accurate, because rep formulas assume every set went to failure. For beginners, a rep formula on a set close to failure is often more reliable, since newer lifters tend to misjudge how many reps they have left.
What is the difference between RPE and RIR?
They describe the same thing from opposite ends. RIR counts reps left in reserve, RPE scores the effort out of 10. RPE = 10 minus RIR, so RPE 8 is 2 RIR, and RPE 9.5 means maybe 1 more rep but no more than that.
Should beginners use RPE?
Beginners can start learning it but should not rely on it for 1RM estimates yet. Rate every set, then check yourself now and then by taking a set to technical failure with a spotter. After a few months your ratings get honest, and the RPE chart becomes a reliable tool.
Train by Feel, Track by Numbers
Log your top sets in 1RM.fit and watch your estimated max move week to week, in kg or lb. Free to start.