Rest Period Calculator Formula

Understand the math behind the rest period calculator. Each variable explained with a worked example.

Use the Rest Period Calculator

Formulas Used

Recommended Rest

rest_seconds = round(base_rest + compound_bonus + rep_adjustment)

Rest in Minutes

rest_minutes = round((base_rest + compound_bonus + rep_adjustment) / 60 * 10) / 10

Minimum Rest

min_rest = round((base_rest + compound_bonus + rep_adjustment) * 0.75)

Maximum Rest

max_rest = round((base_rest + compound_bonus + rep_adjustment) * 1.25)

Variables

VariableDescriptionDefault
intensity_pctIntensity (% of 1RM)(%)80
reps_per_setReps per Set5
is_compoundCompound Exercise1
base_restDerived value= 30 + intensity_pct * 1.5calculated
compound_bonusDerived value= is_compound * 30calculated
rep_adjustmentDerived value= (reps_per_set > 12) * (-20) + (reps_per_set < 5) * 30calculated

How It Works

How Rest Periods Are Determined

Rest between sets depends on training intensity, exercise type, and your goal.

General Guidelines

  • Strength (1-5 reps, 85%+ 1RM): 3-5 minutes
  • Hypertrophy (6-12 reps, 65-85% 1RM): 1-3 minutes
  • Endurance (12+ reps, <65% 1RM): 30-90 seconds

    • Compound movements (squat, deadlift, bench) need more rest than isolation exercises because they recruit more muscle mass and are more neurologically demanding.

    Worked Example

    Squatting at 80% 1RM for 5 reps.

    intensity_pct = 80reps_per_set = 5is_compound = 1
    1. 01Base rest = 30 + 80 * 1.5 = 150 sec
    2. 02Compound bonus = 30 sec
    3. 03Rep adjustment = 0 (5 reps is in 5-12 range)
    4. 04Total = 150 + 30 + 0 = 180 sec = 3.0 min
    5. 05Range: 135-225 sec (2:15 to 3:45)

    Frequently Asked Questions

    What happens if I rest too little?

    You will not fully recover ATP stores, leading to reduced performance on subsequent sets. This limits strength gains but may benefit hypertrophy through metabolic stress.

    Can I rest too long?

    For strength, longer rest is generally fine. For hypertrophy, resting beyond 3-4 minutes may reduce metabolic stress, which contributes to muscle growth.

    Should I time my rest periods?

    Timing rest periods ensures consistency and helps manage total workout duration. It is especially important for hypertrophy-focused training.

    Ready to run the numbers?

    Open Rest Period Calculator