Shower Water Cost from Supplied Flow Calculator

How the calculation works

water cost=flow×minutes×price/m³/1000

Convert constant-flow liters to cubic meters, then apply supplied volumetric price. Stable evaluation selects the smallest nonnegative supplied factor, computes the product of the other two divided by1000, then multiplies by the smallest factor. No units or physical formula change; this avoids premature liters-to-cubic-meters underflow before the supplied price rescales the result. Version3 preserves this expression and adds explicit model constraints: each field is zero or at least 0.000001 in its declared unit. The micro-unit floor is a broad practical input range, not recommended usage or a measurement standard. Zero duration/use and free supplied price remain supported. Positive input cases are many orders above binary64 underflow.

Worked example

With supplied water flow 10 L/min, shower duration 8 min, supplied water price 3 currency/m³, shower water cost from supplied flow is 0.24 currency.

Assumptions and limits

Water-volume charge only; excludes heating, wastewater fees, fixed charges and tariff tiers. Each supplied input accepts zero or 0.000001 through its shown maximum; smaller positive inputs are rejected. Binary64 multi-operation estimates, not exact arithmetic or measurement/invoice accuracy. Show small nonzero estimates with enough significant figures; never relabel them exact zero.