Stop 1 to 2 repetitions shy of technical failure on most working sets.

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A short IZEM video guide for the decisions in this article.

Educational fitness and nutrition information for healthy adults. Nothing on this page is medical advice or a clinical prescription. Stop any movement that causes sharp pain or dizziness, and consult a physician, physical therapist, or registered dietitian for medical or injury guidance.

Complete RIR to RPE conversion chart

Fixed percentages of your one-rep max assume your strength is identical on a rested Saturday morning and after a stressful Tuesday workday. Validated by Helms et al. (2016) and Zourdos et al. (2016), the RIR scale lets you autoregulate your weight on the bar based on how many clean repetitions remain at the end of the set [1] [2].

Why you shouldn't take every exercise to 0 RIR

Meta-analyses comparing training to failure (0 RIR) against stopping 1 to 3 reps short of failure show similar muscle growth when weekly set volume is matched, while 0 RIR causes substantially greater neuromuscular fatigue and longer recovery times [3]. Match your RIR target to the exercise:

• Barbell squats, deadlifts, and bench presses (2 to 3 RIR): Taking Set 1 of squats to absolute failure spikes central fatigue and forces you to strip plates off the bar for Sets 2 and 3. Stopping with 2 clean reps in reserve lets you complete all three sets with the same heavy working weight.
• Dumbbell presses, rows, and lunges (1 to 2 RIR): Independent stabilization makes true 0 RIR awkward to spot, so stopping 1 to 2 reps before form breakdown keeps tension on the target muscle.
• Cables, machines, and single-joint isolation (0 to 1 RIR on the final set): Because lateral raises, curls, pressdowns, and leg curls carry low spinal and systemic fatigue, taking the final set to 0–1 RIR is a safe way to verify that you aren't underestimating your effort.

How to calibrate your RIR when you're not sure

Studies show that lifters are most accurate at judging RIR when a set runs between 6 and 10 repetitions and ends within 0 to 2 reps of failure [2]. When a set goes past 15 repetitions, burning discomfort often tricks people into stopping with 4 or 5 reps still in the tank. Once every three to four weeks, take the final set of a safe machine or cable exercise (like a seated cable row or chest press machine) to technical failure (0 RIR) while counting the reps after the bar starts slowing down. That teaches you exactly what 2 RIR and 1 RIR feel like.

Combine this chart with our One Rep Max (1RM) Calculator and Progressive Overload Tracker Template to log both weight and RIR each week.

Frequently asked questions

What is the difference between technical failure and absolute failure?

Technical failure (0 RIR for safe programming) is the point where you cannot complete another repetition without losing target joint alignment, bouncing the weight, or shifting the load onto other muscles. Absolute failure is when the weight physically stops moving regardless of form.

Should RIR stay the same across all 4 weeks of a training block?

Many structured programs start Week 1 at 2 to 3 RIR while you adapt to the movement volume, move to 1 to 2 RIR in Weeks 2 and 3, and finish Week 4 at 1 RIR (with 0 RIR on isolation final sets) before resetting.

How does RIR relate to percentage of 1RM?

Each repetition in reserve corresponds to roughly 2.5% to 3% of your 1RM. For example, a weight you can lift for 8 reps at 0 RIR (~78-80% 1RM) becomes an 8-rep set at 2 RIR when loaded around 73-75% 1RM.