RPE to percentage chartand 1RM calculator

Fire Your Coach runs this same Epley estimate on every set you log, tracks the trend across blocks, and reads the intensity your plan asked for. The chart above stays free either way.

Fire Your Coach estimates a one-rep max with Epley, and this calculator runs the same line of code. That's the whole reason the page exists. If your estimated max here disagrees with the one in your plan, something is broken, and it's not the arithmetic.

But Epley is one of at least four formulas in circulation, and they don't agree. Brzycki divides rather than multiplies. Lombardi raises reps to a fractional power. O'Conner adds a flat 2.5 percent per rep. Feed all four the same set of 100 kg for 3 reps and they return 110, 105.9, 111.6 and 107.5 kg. Same set, a spread of nearly six kilos, and every one of them is a published, cited equation.

Where they drift is worth knowing. Against Lombardi and O'Conner, Epley reads high and the gap widens as reps climb: at 12 reps Epley says 140 kg where O'Conner says 130 and Lombardi says 128.2. Against Brzycki the picture reverses partway. The two cross at exactly 10 reps, both landing on 133.3 kg. Below 10 reps Epley is the higher of the two, above 10 reps Brzycki is, and Brzycki keeps climbing until it breaks entirely near 37 reps.

We picked Epley for a boring reason. It's the formula most commonly implemented in the trackers our users import from, so an estimated max that carried over from Strong or Hevy lands close to where it started. A different formula would have been defensible. Silently switching between them wouldn't.

Every cell answers the same question: how many reps you'd have got if you'd kept going. RPE 8 means two were still there. So five reps at RPE 8 and seven reps at RPE 10 are the same set as far as the load is concerned, and the chart gives both of them 81.1 percent.

That's why the numbers run in diagonals rather than down columns. Follow 81.1 percent across the grid and you find 7 reps at RPE 10, 6 at RPE 9, 5 at RPE 8, 4 at RPE 7 and 3 at RPE 6. Five different sets, one number, because they all cost the bar the same thing.

Which means you only need one piece of arithmetic to use any of it: reps to failure equals reps completed plus ten minus your RPE. Find that total in the reps column, read the RPE 10 value, and you've got your percentage. Everything else in the table is the same answer written out for convenience.

Worked through: 140 kg for 5 at RPE 8. Two in reserve makes seven reps to failure. Seven reps is 81.1 percent, so 140 divided by 0.811 puts your max near 172.6 kg. Eighty percent of that is 138 kg, which is roughly the weight already on the bar. That's the point of the exercise. Not a verdict on how strong you are, a number you can load next Tuesday.

Subtract the RPE from ten and you have the reps in reserve. RPE 10 is 0, RPE 9 is 1, RPE 8 is 2. Half points behave the same way, so RPE 8.5 is one and a half reps left. There's no conversion table required and no source anywhere that disagrees, because this half is a definition rather than a measurement.

The scale that made it usable is the repetitions-in-reserve RPE scale from Zourdos and colleagues in 2016. Its contribution was replacing "how hard did that feel" with "how many more could you have done". The second question has an answer you can check against the next set.

The same study carries the caveat worth keeping. Experienced squatters rated their sets more accurately than novices did. If you've been under a bar for a decade, your RPE 8 is probably an RPE 8. If you started in March, your RPE 8 is often nearer a 6, and every percentage downstream of it inherits that error quietly.

Fire Your Coach reads both dialects because coaches write in both. A prescription arriving as RPE 8, as 2 RIR, as 75 percent or as Zone 2 is parsed into a stored intensity kind, so what your coach wrote is what you see. When readiness is poor the app eases the effort target rather than guessing at a new weight: it adds a rep to your reserve on strength work, and drops a protocol's RPE target by two points. Same scale, used as a control surface.

The percentage columns come from the Reactive Training Systems chart published by Mike Tuchscherer, which is why RPE became a loading language in strength sport rather than a private feeling. It's an average of many lifters. It was never a law about any one of them.

Three things move it, and they move it by more than the chart's own precision. The lift: a five-rep squat and a five-rep deadlift aren't the same fraction of their respective maxes for most people. The lifter: training history and how comfortable you are near a true limit both change how many reps you own at a given percentage. And the distance from a single, because the further out you go the more the estimate is doing on its own.

There's evidence for the first one. LeSuer and colleagues tested seven prediction equations across the bench press, squat and deadlift in 1997. Correlations were high across the board, above 0.95, and every single equation still understated the deadlift. One number doesn't travel across three lifts, which is a limit of the method rather than a flaw in any particular table.

The published charts also disagree with each other. Checking three copies of "the RPE chart" in August 2026 returned three answers for ten reps at RPE 10: 73.9 percent, 75 percent and 77.5 percent. On a 140 kg lift that spread is about five kilos. So pick one chart and stay on it. Which table you chose matters far less than whether last month's session and this one were read off the same one.

That disagreement is worst in the shaded corner of our own table, which is why it's shaded. Everything at ten reps to failure or fewer is solid and every published version agrees on it. Past that, the versions drift, and at the very corner one chart calls 12 reps at RPE 6 a 57.2 percent effort while another calls it 61.8. Both cannot be right and we have not been able to find out which is. Those cells are there because a chart that stops early is annoying, not because we would program from them.

Use it to choose a starting load, then let the set correct you. If the chart says 81 percent and 81 percent came up at RPE 9.5, the chart was wrong about you. That's not a failure of the method. That's the method working.

Both the chart and Epley claim to give you a one-rep max, and they don't match. This is the part most calculators leave out, so here it is with numbers.

Take reps to failure and ask each method what it implies. At seven reps they agree almost exactly, Epley landing within 0.02 percent of the chart. Below seven Epley reads high, peaking at 3.3 percent over at a single. Above seven it reads low, and by twelve reps it's 2.6 percent under. Neither is drifting because it's broken. They were fitted to different data and they cross where the data overlapped.

The practical consequence is small and worth knowing anyway. If you log heavy singles and doubles, your Epley estimate flatters you slightly. If you log sets of ten, it undersells you slightly. Since Fire Your Coach applies the same formula to every set you've ever logged, the bias is constant and the trend across a block is still clean. A number that's consistently 2 percent low is a perfectly good measuring stick. A number that changes formula halfway through isn't.

Conditioning work. A percentage of a one-rep max means nothing in an interval session, an EMOM or a sled push, because what limits you there is pace and recovery rather than load. The RPE half still travels perfectly well and Fire Your Coach uses it on protocols too. The percentage half doesn't, and forcing it produces a number with no referent.

Machines and small isolation work. Cable stacks, pin-loaded machines and lateral raises all have rep-max curves of their own, and they aren't the barbell's. The chart was built on squat, bench and deadlift. A 20-rep leg extension isn't 61.8 percent of anything you would want to attempt for a single.

Sets past about twelve reps. Every formula on this page is extrapolating up there and they stop agreeing, sometimes by ten percent or more. The calculator will still give you an answer above twelve reps, with a caution attached, because refusing outright is unhelpful. Treat it as a direction.

Your first weeks back. After time off, your RPE calibration is the thing that decayed fastest. Ratings come back within a few sessions, but until they do, the chart is faithfully converting an input that's wrong.

Everything above is a conversion. It tells you what a number means today, and it'll still be right in a year with no account and nothing to sign up for. Bookmark it and use it.

What it can't do is remember. It doesn't know your estimated max was climbing for six weeks and then stalled, that the stall started when you moved to a different squat variation, or that you've run the same top set at RPE 9 for three blocks and the reps haven't moved. Those questions need a record with reasoning attached, and that's a different tool.

Fire Your Coach computes this same estimate from every set you log, tracks it per lift across blocks, and keeps the intent behind each prescription so the next block starts from what happened rather than from a blank page.

RPE, RIR, percentage or zone: the parser keeps whichever your program used and shows it on the set, so you are not translating between three scales in a notebook mid-session.