RIR and RPE Explained: How Hard to Train for Strength and Muscle

RIR and RPE explained, simply: both describe how close your set is to failure. RIR counts reps left in the tank; RPE converts that effort to a 1-10 scale.

Quick answer: most productive sets are close to failure, not at failure. For most lifters, that means finishing working sets around RIR 1-3 (roughly RPE 7-9).

This guide makes RIR/RPE practical: how to estimate effort, how to set targets for strength and hypertrophy, and how to use logging without turning training into math homework.

Available now on the App Store.

Contents

What is RIR?

RIR means reps in reserve: how many more good reps you could have done if you had to.

• RIR 3: you probably had ~3 clean reps left.
• RIR 1: you had ~1 clean rep left.
• RIR 0: you hit failure or the next rep would have been a grind with form breakdown.

Think “clean reps,” not “I could maybe ugly-grind one more.” Consistency matters more than perfection.

What is RPE?

RPE is rating of perceived exertion: a 1-10 effort score where higher means harder. In lifting, RPE usually maps to “how close you were to failure.”

In practice, RPE and RIR describe the same thing from two angles. Most people find RIR easier to estimate because it is a concrete question: “How many reps were left?”

RIR vs RPE: which one should you use?

Use RIR if you want something simple and repeatable. Use RPE if you already think in RPE (common in strength circles) or you like a single number.

Quick conversion: RIR to RPE

Use this as a rough translation, not a law of physics:

How to estimate your RIR (without guessing)

RIR gets more accurate over time. The goal is not perfection; it is being consistent enough that “RIR 2” means the same thing from week to week.

• Count reps you could repeat with the same form: stop when bar speed slows and technique starts to change.
• Use rep quality as the guardrail: the set ends when the next rep would be a grind or a cheat.
• Calibrate occasionally: once in a while (not every set), take a safe set close to failure on an accessory and compare your guess to reality.

If you want a clean system for seeing your previous sets before you lift, start with Workout Log: Track Sets, Reps, and Weight.

How hard should you train? (By goal)

You can make progress across a range of efforts. The practical win is picking a target and repeating it consistently.

If fatigue is building and effort is creeping up across the board, that is often your cue for a deload week.

Strength focus

For strength, you usually want high-quality reps and crisp technique. Sets that turn into grinders can add fatigue fast.

• Most volume: RIR 2-3 (RPE 7-8)
• Occasional top sets: RIR 1 (RPE 9)
• Testing days: RIR 0-1 (RPE 9-10), used sparingly

Muscle (hypertrophy) focus

For muscle, getting close to failure matters more, especially on safe exercises. The big mistake is taking every heavy compound to failure and wondering why recovery falls apart.

• Most sets: RIR 1-2 (RPE 8-9)
• Some sets to failure: RIR 0 (RPE 10) on stable accessories, not on risky barbell lifts

How to progress using RIR

RIR is useful because it helps you keep effort consistent while you apply progressive overload.

Example: your plan calls for 3 sets of 6 on bench at RIR 2.

• Week 1: 185 × 6, 6, 6 @ RIR 2
• Week 2: 185 × 7, 6, 6 @ RIR 2 (add a rep where you can)
• Week 3: 185 × 7, 7, 6 @ RIR 2
• Week 4: 190 × 6, 6, 6 @ RIR 2 (add load when you “filled” the reps)

That is the same idea as our progressive overload guide, just with an effort guardrail so you do not overshoot.

When to train to failure (and when not to)

Training to failure can be a useful tool, but it is not required for progress. It is easiest to justify on exercises that are safe and stable.

• Better candidates: curls, lateral raises, leg extensions, machine presses.
• Riskier candidates: heavy squats, deadlifts, barbell bench without safeties, technical Olympic lifts.

If rest time is what limits you from staying close to your target effort, read How Long to Rest Between Sets.

How to track RIR/RPE cleanly

Effort tracking works best when it is optional and lightweight. Log it when it helps you stay honest (or when your day-to-day readiness varies), and skip it when it does not.

Push/Pull supports RIR & RPE tracking per set so you can keep effort consistent without cluttering your log.

In the app

FAQ

Related reading

• Progressive Overload Explained
• Deload Week: When to Deload, How to Do It, and What to Track
• How Long to Rest Between Sets: A Simple Guide
• Workout Log: Track Sets, Reps, and Weight Without Overthinking

Make effort consistent without overthinking

Push/Pull is a clean workout tracker with fast set logging, rest timers, and optional RIR/RPE fields when you want them. Keep the log simple, keep effort consistent, and let the weeks stack.

Available now on the App Store.