5/3/1 Calculator

The calculation relies on two foundational phases: estimating your maximum strength and applying strict percentage guidelines across a four-week wave. First, your one-rep maximum (1RM) is estimated using the Epley formula: 1RM = Weight × (1 + (Reps / 30)). Next, the program calculates your working sets based on predetermined percentages of your training max (typically 90% of your true 1RM) across a four-week cycle: Week 1 uses 65%, 75%, and 85%; Week 2 uses 70%, 80%, and 90%; Week 3 uses 75%, 85%, and 95% for peak intensity; and Week 4 scales back with a deload phase of 40%, 50%, and 60%.

Imagine you perform a set of the back squat where you lift 200 lbs for 5 repetitions. First, we calculate your estimated 1RM using the formula: 200 × (1 + (5 / 30)) = 200 × 1.1667 = 233.34 lbs. Assuming your training max is set at 90% of this value (210 lbs), the calculator determines your Week 1 working sets. For Set 1, you multiply 210 by 0.65 to get 136.5 lbs (rounded to 135 lbs). For Set 2, 210 multiplied by 0.75 yields 157.5 lbs (rounded to 155 or 160 lbs depending on microplates). For Set 3, 210 multiplied by 0.85 gives 178.5 lbs (rounded to 180 lbs). This progressive framework ensures steady, sustainable strength gains.

Start lighter than you think is necessary to allow room for long-term progression without stalling. Always use a conservative training max rather than your absolute lifetime personal record. Finally, never skip the Week 4 deload phase; allowing your central nervous system to recover is critical for avoiding plateaus and injuries.