Coolant & antifreeze mix calculators
Calculate concentrate and water amounts for a fresh coolant mixture. Your vehicle manual and coolant label choose the percentage.
Use the percentage specified by the vehicle manufacturer and exact coolant product. These presets make a fresh concentrate-and-water mixture; they do not decide compatibility. Correcting coolant already in a system is a different calculation requiring system volume and measured starting concentration.
Calculate a fresh coolant mixture
Start with a 50/50 mixture sized for a 1 gallon container. Adjust the percentage, unit, and total only after checking the vehicle manual and coolant instructions.
Defaults: 1 gallon total, 50/50 split.
Popular use cases
- Making a fresh 50/50 concentrate-and-water batch after a complete drain
- Scaling a label-approved 60/40 mixture to liters or gallons
- Preparing a small top-off bottle that matches the coolant already in the system
- Checking the concentrate and water split before filling a clean container
Fresh coolant mixtures by percentage
30% coolant / 70% water
Neutral volume calculations for a 30/70 mixture when your manual and product permit it.
40% coolant / 60% water
Neutral volume calculations for a 40/60 mixture when explicitly specified.
50% coolant / 50% water
Equal concentrate and water amounts for products and vehicles that specify 50/50.
60% coolant / 40% water
A 60/40 mathematical split; verify that both the product and vehicle allow it.
70% coolant / 30% water
A 70/30 mathematical split for products and vehicles whose instructions permit that maximum.
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FAQs
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?
No. Correcting an existing system requires the system capacity and its measured starting concentration. This page only calculates a fresh concentrate-and-water mixture.
What if I need a different container size?
Change the total volume in the mixer. The coolant percentage remains the same while the concentrate and water amounts scale to the new total.
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.