Fork oil mixing calculator

If you need, say, 7.5W fork oil but have 5W and 10W, you can mix them. The calculator shows how much of each oil to use.

Result

Oil A (5W)	250 ml (50 %)
Oil B (15W)	250 ml (50 %)

Results are calculated estimates. Always check your vehicle manufacturer's instructions.

Matching products: Front shock oils

Enter the viscosity (W) of both oils you have and the viscosity you want.
Enter the total amount of oil you need (ml, see the service manual).
Use two oils from the same brand – W numbers from different brands are not exactly comparable.

Can I mix oils from different brands?

Better not: one brand's 10W can have a different actual viscosity than another's. Oils from the same brand mix predictably.

How accurate is the result?

The calculator uses a linear approximation, which is accurate enough in practice when the W numbers are close (e.g. 5W and 15W).