Coolant Mix Ratio Calculator
Calculate the right antifreeze to water ratio for your climate.
See freezing and boiling point protection.
Coolant Mix Result
Coolant (antifreeze) must be mixed with water in the right ratio for proper engine protection.
Standard mix ratios:
| Ratio (Antifreeze:Water) | Freeze Point | Boil Point |
|---|---|---|
| 30:70 | -17°F (-27°C) | 235°F (113°C) |
| 40:60 | -34°F (-37°C) | 240°F (116°C) |
| 50:50 | -34°F (-37°C) | 265°F (129°C) |
| 60:40 | -62°F (-52°C) | 270°F (132°C) |
| 70:30 | -84°F (-64°C) | 277°F (136°C) |
Recommended: Most manufacturers recommend a 50:50 mix for the best balance of freeze protection, boil protection, and cooling efficiency.
Never exceed 70% antifreeze — higher concentrations actually reduce cooling efficiency and freeze protection.
Use distilled water — tap water contains minerals that can cause deposits and corrosion.