Calculators / RIR / RPE converter

RIR to RPE calculator

Convert a set's effort between RIR (reps in reserve — how many more you could have done) and RPE (rate of perceived exertion, rated 6–10). This is the exact rule Zyra Workouts applies when you log a set: whole numbers, clamped to the scale. Training guidance, never medical advice.

RPE (6–10)

Reps in reserve

RIR 2

RPE used

RPE 8

What it means

Two more reps were possible — the app’s default target for most working sets.

RPE 64 RIR
RPE 73 RIR
RPE 82 RIR
RPE 91 RIR
RPE 10failure

Not yet on the App Store — about Zyra WorkoutsRuns in your browser — nothing you type is sent anywhere.

How the math works

Two lines, the same in both directions. The only subtlety is the clamp.

RIR = 10 − clamp(round(RPE), 6, 10)
RPE = 10 − clamp(round(RIR), 0, 4)

round first, because the app stores effort as a whole number. clamp second, because the app's scale stops at RPE 6 / RIR 4: a set with five or six reps left is recorded as “4 or more”, not as RPE 5 or 4. That is why RIR 5 converts to RPE 6 rather than 5 — the converter tells you when it clamped.

The ladder

RPE	RIR	In plain terms
6	4	Four or more reps — the lightest effort the scale records.
7	3	Three more reps — comfortable.
8	2	Two more reps were there — the app’s default working-set target.
9	1	One more rep was there.
10	0	The last rep was the last possible rep.

Fig. The RPE ↔ RIR ladder the app converts on: RPE (rate of perceived exertion, 6–10) maps to RIR (reps in reserve — how many more reps you could have done) as RIR = 10 − RPE. Inputs outside the scale clamp: an RPE below 6 reads as RIR 4, an RIR above 4 reads as RPE 6. A logging convention, not a measurement of effort.

The 6–10 RPE to 4–0 RIR ladder the app logs against. Effort ratings are self-reported, not measurements.

Source: the Zyra Workouts set-logging rule (fit-engine rir.ts, ported verbatim from the app).

Frequently asked

What is RPE 8 in RIR?

RPE 8 is RIR 2: on the 6–10 scale the app uses, reps in reserve = 10 − RPE, so an RPE 8 set is one where 2 more reps were possible.

What is RIR 2 in RPE?

RIR 2 is RPE 8. The scale is symmetric: RPE = 10 − RIR, so 2 reps in reserve is an 8 out of 10.

Why does RIR 5 come out as RPE 6?

The app's logging scale only records RIR 0–4 (RPE 6–10). Anything lighter is clamped to the top of the range, so RIR 5 converts to RPE 6, the same as RIR 4. Sets that easy are usually warm-ups, which the app tracks as their own set type rather than by effort.

Does the converter accept half points like RPE 8.5?

It accepts them, but rounds first: the app stores whole numbers, so RPE 8.5 rounds to 9 (RIR 1) and RPE 8.4 rounds to 8 (RIR 2). The widget says so under the result when a value was rounded.

Which is better to log, RIR or RPE?

They carry the same information on this scale, so it is a preference. Zyra Workouts logs RIR because "how many more could I have done" is a count you can check against the next set, while RPE asks for a rating.

Is this training advice?

It is a unit conversion — arithmetic on a number you enter, with no recommendation about how hard to train. Training guidance only, never medical advice.

Other training calculators

1RM calculator Plate calculator Warm-up set builder Weekly sets calculator

Log RIR on every set

Zyra Workouts records reps, weight and RIR per set, and its progression rule reads the RIR to decide when the weight steps up. The app is in development and not yet on the App Store.

Not yet on the App Store — about Zyra Workouts

Zyra is a training and nutrition tracking tool. Nothing on this page is medical advice, a diagnosis, or an individual prescription. The numbers are estimates from published formulas and the apps' own rules — consult a qualified professional for decisions about your health, and a coach for your training.