MixByParts

Coolant & antifreeze mix calculators

Calculate concentrate and water for your final mixture.

For coolant concentrate + water. Do not dilute ready-to-use premix unless its instructions explicitly say to.

Enter a number in the selected unit.

Use the percentage of the final volume from your instructions. If your concentrate recipe says 50/50 concentrate:water, enter 50 or 50%. A 50/50 premix bottle is a different product.

Use your vehicle manual and exact concentrate label for the allowed percentage and water type.

How much antifreeze and water do I need?

For a fresh mixture, multiply the final volume by your instructed concentrate percentage ÷ 100. Water is the final volume minus the concentrate amount.

Example only: a 5 L final mixture at 50% contains 2.5 L concentrate + 2.5 L water. Enter 5 L as the final mixture amount, not 5 L of water.

The calculator splits a volume you supply; it does not know your vehicle’s cooling-system capacity. Use your vehicle manual and exact concentrate instructions for capacity, compatibility, percentage and water type. Ready-to-use premix is a different product.

Coolant concentrate / water reference chart

Arithmetic examples for 5 L of finished mixture, by volume. Choose the allowed concentration from the vehicle manual and exact product instructions; these are not recommendations. Use concentrate, not ready-to-use premix.

Concentrate %Concentrate : waterConcentrate + water
(5 L final mixture)
30%30/701.5 L + 3.5 L
40%40/602 L + 3 L
50%50/502.5 L + 2.5 L
60%60/403 L + 2 L
70%70/303.5 L + 1.5 L
Help and sources

How much antifreeze do I need for a fresh mixture?

Multiply the final mixture volume by the instructed concentrate percentage divided by 100. For example, a 1 US gallon final mixture at 50% contains 0.5 US gallon concentrate and 0.5 US gallon water. The vehicle manual supplies the cooling-system capacity; this calculator does not determine it.

How much concentrate do I add to water already measured?

The calculator above asks for final mixture volume, not water alone. For a product-approved 50/50 concentrate:water mixture, 1 litre of measured water needs 1 litre of concentrate, making 2 litres in total. This example uses concentrate; do not dilute ready-to-use premix unless its instructions say to.

How do I choose the right coolant percentage?

Use the vehicle owner’s manual or service information together with the current instructions for the exact coolant product. MixByParts calculates a percentage you supply; it does not determine compatibility or the correct concentration.

Is this for concentrate or premixed coolant?

These calculations are for coolant concentrate mixed with the water type specified by the product. Do not add water to a ready-to-use premix unless its instructions explicitly tell you to.

Can this correct coolant that is already in the vehicle?

Use the separate coolant correction calculator linked above. It requires system capacity, measured current concentration, chosen target, and replacement-fluid concentration. The fresh-mixture calculator here remains for concentrate and water.

What if I need a different container size?

Change the final mixture amount. The concentrate percentage stays the same while both liquids scale.

Why are these calculations by volume?

Coolant density varies by product and concentration. The presets avoid generic OAT or HOAT density assumptions. If you must mix by mass, use density data from the exact product information or safety data sheet.

Example of product-specific coolant guidance
Browse 50 coolant presets

Volume examples only. Match the ratio and basis to your exact product.