Soap Bar Lifespan Calculator

Soap Bar Lifespan Calculator: Plan Your Restocking

A bar of soap wears down at a fairly predictable rate once you know your shower frequency and how much lather you typically use. This calculator estimates how many weeks a bar will last so you can time your next purchase.

The Formula

Weeks Lasting = Bar Weight / (Grams per Shower × Showers per Week)

Worked Example

A 120-gram bar, using 8 grams per shower, showering 7 times a week.

Weeks Lasting = 120 / (8 × 7) = 2.14 weeks

How to Use This Calculator

1. Enter the soap bar's weight in grams.
2. Enter roughly how many grams you use per shower.
3. Enter your showers per week.
4. Click Calculate to see how many weeks the bar will last.

Related Calculations

Use with the Shower Water Usage Calculator for a fuller picture of your shower routine.