Coolant Concentration Calculator

Sump Volume

Refractometer Factor

Brix Reading × Factor = Actual %. Check your coolant barrel.

Current Brix Reading

°Bx

Target Percentage (%)

Concentration Guide

Proper concentration is vital for tool life, rust prevention, and preventing bacterial growth (the "Monday morning smell").

Typical Targets:

5 - 7%: General milling and turning.
8 - 10%: Tapping, heavy reaming, or tough alloys.
Under 4%: High risk of rust and poor tool life.

Water Quality Matters

Always use deionized or RO water if possible. Minerals in tap water build up over time as water evaporates, causing "hardness" that can break down your coolant emulsion.

Pro Tip: Always add concentrate TO water (O.I.L. - Oil In Last). Never pour water into concentrate as it creates an unstable "inverted" emulsion.