Progressive Overload Calculator — What Should You Lift Next?

March 2026 · Interactive Tool · Based on Epley (1985) + Auto-Regulation (Zourdos 2023)

You trained last week. But what do you put on the bar this week? This calculator estimates your 1RM from your last performance and tells you the optimal weight for your next session — adjusted for your target reps and target RIR.

YOUR LAST PERFORMANCE

YOUR NEXT SESSION

Recommended weight for your next session
Your e1RM
Change
% of 1RM

What Is Progressive Overload?

Progressive overload is the fundamental principle behind muscle growth. It states: your muscles only grow when exposed to a greater stimulus than last time. Without progressive overload, there is no adaptation — no matter how often you train.

The stimulus can increase in three ways:

All three increase your e1RM (estimated one-rep max) — and that's the true measure of progress.

Key insight: Progressive overload doesn't mean adding weight every week. It means your e1RM rises over weeks and months. Sometimes you progress through more reps, sometimes through better technique (lower RIR), and sometimes through more weight. This calculator accounts for all three factors.

How the Calculator Works

The calculator uses the Epley formula (1985) — the same formula MUSCLE TECHNICS uses internally:

e1RM = Weight × (1 + (Reps + RIR) / 30)

By factoring in RIR, your e1RM reflects your true capacity — not just what you actually lifted, but what you could have lifted. This is the foundation for precise weight recommendations.

From your e1RM, the calculator works backwards: what weight do you need to hit your target reps at your target RIR?

When to Increase — and When Not To

Increase the weight when you hit your target reps at RIR 2 or lower. This means you have room to progress.

Keep the weight when you barely hit your target reps at RIR 0-1. You're at your limit — increasing would compromise form.

Reduce the weight when you couldn't complete your target reps, or when returning from a break (deload, illness).

The research says: Robinson et al. (2024) analyzed 54 studies and found that training at RIR 1-3 is equally effective for muscle growth as training to failure (RIR 0) — with significantly less fatigue and injury risk. Zourdos et al. (2023) confirmed that RIR-based auto-regulation is the most effective method for managing training intensity.

Realistic Progression Rates

Frequently Asked Questions

What if the calculator suggests less weight than last week?
This happens when you increase your target reps or lower your target RIR. Example: 80kg × 6 @ RIR 2 has an e1RM of ~98kg. If you now want 10 reps @ RIR 2, you need ~73kg — less weight but the same relative intensity. Your e1RM stays the same; you're just training in a different rep range.
Should I use the same weight for every set?
Yes, for most hypertrophy programs, "straight sets" (same weight, same reps, all sets) are most effective. This calculator gives you the weight for this standard approach. MUSCLE TECHNICS automatically adjusts weights if your RIR during training is higher or lower than planned.
More weight or more reps — which is better?
Both create progressive overload. Research (Schoenfeld 2017) shows hypertrophy is equally effective across 6-30 reps — as long as intensity is sufficient (RIR 0-3). For beginners, more weight at the same reps is simplest. For advanced lifters, switching to more reps (same RIR) can provide new growth stimulus.
How often should I increase?
Try to progress every session — whether through more weight, more reps, or lower RIR. If you can't progress for 2-3 weeks, you've hit a plateau and should adjust training volume or exercise selection.

Automatic Progressive Overload

MUSCLE TECHNICS calculates your optimal weight for every set automatically — based on your e1RM, RIR, and the science-backed rep range. No manual calculations needed.

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→ Progressive Overload: The Only Rule That Builds Muscle → RIR Explained: Why Failure Isn't Always Optimal → 1RM Calculator: Estimate Your One Rep Max → How Many Sets Per Muscle Group? The Answer From 67 Studies All articles →