Coolant Mixture Calculator

Calculate optimal antifreeze/water ratios for freeze and boil protection in your climate.

Check owner's manual for system capacity
50/50 mix is recommended for most applications
Amount (same units) | Current concentration (%)

Concentration Protection Chart

Antifreeze %Freeze PointBoil Point*
30%-17F / -27C235F / 113C
40%-25F / -32C242F / 117C
50%-34F / -37C265F / 129C
60%-62F / -52C270F / 132C
70%-84F / -64C276F / 136C

*Boil points shown with 15 PSI radiator cap. Values for ethylene glycol.

Coolant Mixing Guidelines

Best Practices

  • Always use distilled water, never tap water
  • 50/50 is optimal for most climates and vehicles
  • Never exceed 70% antifreeze concentration
  • Higher than 70% actually reduces protection
  • Check coolant condition annually with test strips

Coolant Types

  • Green (IAT): Traditional, change every 2 years
  • Orange (Dex-Cool): Extended life, 5 years
  • Pink/Red (HOAT): Hybrid, 5+ years
  • Blue (Asian): Phosphate-based for Asian vehicles
  • Never mix different coolant types