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RIR calculator (reps in reserve)
For lifting: enter your one-rep max and the weight and reps of a set, and the calculator shows how many reps in reserve (RIR) that set left, the matching RPE, and the load for the same reps at 0 to 4 in reserve. The RIR chart below gives the percentage of max for every reps and RIR pair.
Example result
2
8
At 80% of your max, a set to failure is about 8 reps.
| Stopping point | Reps at 80 kg | Load for 6 reps |
|---|---|---|
| 0 in reserve (RPE 10) | 8 | 85 kg |
| 1 in reserve (RPE 9) | 7 | 82.5 kg |
| 2 in reserve (RPE 8) | 6 | 80 kg |
| 3 in reserve (RPE 7) | 5 | 80 kg |
| 4 in reserve (RPE 6) | 4 | 77.5 kg |
Reps in reserve chart
Percentage of one-rep max by reps done and reps left in reserve, with the matching RPE. Multiply a cell by your max for the load.
| Reps | RIR 0 (RPE 10) | RIR 1 (RPE 9) | RIR 2 (RPE 8) | RIR 3 (RPE 7) | RIR 4 (RPE 6) |
|---|---|---|---|---|---|
| 1 | 100% | 97% | 94% | 91% | 88% |
| 2 | 97% | 94% | 91% | 88% | 86% |
| 3 | 94% | 91% | 88% | 86% | 83% |
| 4 | 91% | 88% | 86% | 83% | 81% |
| 5 | 88% | 86% | 83% | 81% | 79% |
| 6 | 86% | 83% | 81% | 79% | 77% |
| 8 | 81% | 79% | 77% | 75% | 73% |
| 10 | 77% | 75% | 73% | 71% | 70% |
| 12 | 73% | 71% | 70% | 68% | 67% |
RIR calculator examples
Four lifters checking a set against their max. The useful answer is usually the gap between the RIR they felt and the RIR the max predicts.
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Example 1
Fives that were easier than planned
An intermediate lifter with a 315 lb squat who did 245 lb for 5 and meant it to be 2 reps from failure.
- Your 1RM
- 315 lb
- Weight of the set
- 245 lb
- Reps you did
- 5
- Reps in reserve4
- Same as RPE6
Four left is an easy set when the plan was 2. Open it with these numbers and use the load the table gives for 5 reps at 2 in reserve next session.
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Example 2
Checking an RIR call on the bench
A woman with a 60 kg bench who did 50 kg for 5 and felt she had 3 or 4 left.
- Your 1RM
- 60 kg
- Weight of the set
- 50 kg
- Reps you did
- 5
- Reps in reserve2
- Same as RPE8
Her max says about 2 left, so she was closer to failure than it felt. That's worth knowing before she sets RIR targets: her "3 left" is closer to a 2.
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Example 3
A set that beat the max
A lifter with a 100 kg max on file who did 85 kg for 8.
- Your 1RM
- 100 kg
- Weight of the set
- 85 kg
- Reps you did
- 8
- Reps in reserve0
A 100 kg max predicts about 6 reps at 85 kg, so 8 means the max on file is out of date. Estimate the new one from this set on the one-rep max calculator and rerun the numbers.
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Example 4
High reps for an older lifter
A 55-year-old with a 185 lb bench, doing sets of 12 at 135 lb and calling them 2 or 3 reps from failure.
- Your 1RM
- 185 lb
- Weight of the set
- 135 lb
- Reps you did
- 12
- Reps in reserve0
- Same as RPE10
The max says those sets ended at failure, not 2 or 3 reps short of it. High-rep sets are where RIR guesses drift most, so either keep the effort and know it's hard, or drop 5 to 10 lb to put a real buffer back.
How accurate is your RIR?
Less accurate the further you are from failure. In a study of 25 trained men squatting 70% of their max to failure, the reps left they called were off by about 2 at RPE 9, 3.7 at RPE 7 and 5 at RPE 5, and longer sets made the guesses worse. Training age didn't predict who was accurate.
That's what this calculator is for: it checks the RIR you felt against what your max predicts. If the two keep disagreeing in the same direction, trust the pattern and adjust your calls. The reps in reserve guide covers how to judge it set by set.
Reading the RIR chart
Each row is the reps you plan to do, each column the reps you want left. A set of 5 with 2 in reserve is a 7-rep effort, so it shares a cell with 7 reps to failure. The chart also works as an RPE chart: RIR 2 is RPE 8.
For the RPE version with half steps and loads from your max, see the RPE chart.
How reps in reserve are calculated
The calculator runs Epley's formula backwards, in the form the RIRLift app uses: from the weight as a share of your max it works out how many reps you could have done to failure, rounded down to whole reps. Your reps in reserve are the difference between that and the reps you did.
The load column runs it forwards: max ÷ (1 + (reps + RIR − 1) ÷ 30), rounded to 2.5 kg or 5 lb.
reps to failure = 30 × (max ÷ weight − 1) + 1, rounded down
RIR = reps to failure − reps done
30 × (100 ÷ 80 − 1) + 1 = 8.5, rounded down to 8
8 − 6 = 2 reps in reserve (RPE 8)Make it fit you
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Use a recent max
An out-of-date max makes every set look closer to failure than it was. Re-estimate from your best set of the last few weeks before trusting the answer.
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Check heavy sets first
Your calls are most accurate near failure, so calibrate on sets of 3 to 6. Once those match, compare your higher-rep sets.
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Go to failure now and then, safely
A set to failure on a machine or a safe lift is the only direct check on your calls. RIR vs going to failure covers when it's worth it.
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Use one max per lift
A bench max says nothing about your incline press. Enter the max for the exact lift and setup you did the set on.
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Plan the next session from the load column
Pick the reps and reps in reserve you want next time and read the load from the table, rounded to your plates.
Questions
What does RIR mean in lifting?
Reps in reserve: how many more clean reps you could have done when you ended the set. 0 RIR is failure, 2 RIR means two left. The reps in reserve guide covers it in full.
How do I know how many reps I have in reserve?
Rate the set right after you rack it by how the last rep moved. Then check the call against your max here, and adjust if your feel and the numbers keep disagreeing.
What RIR should I train at?
Usually 1 to 3 for muscle growth and 2 to 3 for heavy compound lifts, with more in reserve early in a block. How to use RIR sets targets by goal and across a block.
Is RIR the same as RPE?
They measure the same thing on different scales: RPE is 10 minus RIR, so 2 in reserve is RPE 8. RPE vs RIR explains which is easier to log.
Does 0 RIR mean failure?
Yes: no clean rep left. Whether to train there is a separate question, which RIR vs going to failure answers.
Related calculators and templates
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RPE calculator
Your max from a set rated by RPE, and the load for the next set.
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RPE chart
The same percentages by RPE, with half steps.
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One-rep max calculator
A current max from any set, the input this calculator depends on.
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Reps in reserve guide
What RIR is and how to judge it honestly.
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How to use RIR
Targets by goal and how to progress them across a block.
Sources
Log the reps you had left
Record load, reps and RIR on every set and RIRLift keeps each lift's estimated max current from your best working set, then uses your RIR to pick the next set's weight.
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