Cleaning Solution Dilution Ratio Calculator: How Much Concentrate and Water to Mix

How it works

Fill a container: concentrate = total ÷ (N + 1), water = total − concentrate · Add to water: concentrate = water ÷ N · From oz per gallon: N = 128 ÷ oz · From percent: N = (100 − %) ÷ %

A dilution written 1:32 means one part concentrate to 32 parts water, so the finished mix has 33 equal parts, not 32. To fill a bottle of fixed size, divide the bottle’s volume by (N + 1) to get the concentrate and fill the rest with water. Dividing by N alone is the classic error that leaves the bottle slightly too strong; on a 1:4 or 1:10 mix the difference is large. If you instead measure out water first (a gallon of water in a bucket, say) and add concentrate to it, divide the water by N. This is the basis of the common shortcut “ounces per gallon = 128 ÷ N”: a 1:32 product is 4 oz per gallon of water and a 1:128 product is 1 oz per gallon. Both methods give exactly the same strength; they only differ in what the volume you start from means, which the calculator lets you choose. Labels also state dilutions as ounces per gallon or as a percentage. The calculator converts either to a ratio (N = 128 ÷ oz per gallon; N = (100 − %) ÷ %), shows the concentrate in your unit, mL, tablespoons and teaspoons, a chart for common ratios, and, if you enter a container size and price, how many batches one container makes and what each costs. Volumes use US customary units (1 fl oz = 29.57 mL, 1 tbsp = 14.79 mL).

Worked example

For a 1:32 cleaner in a 32 fl oz spray bottle: 32 ÷ (32 + 1) = 0.97 fl oz of concentrate (28.7 mL, about 1.94 tablespoons), then top up with 31.03 fl oz of water. The same 1:32 strength is 4 fl oz per gallon of water and 3.03% concentrate.

Sources: Betco — A quick guide to calculating dilution ratios (128 ÷ ratio = ounces per gallon) · Triple S — Dilution control conversion chart · SweptWorks — Cleaning chemical dilution calculator

Frequently asked questions