E30 Blend Calculator

Work out how much E85 and pump gas to mix for your target ethanol blend.

Your fuels

Target blend (% ethanol)

E85 ethanol % (actual)

Pump gas ethanol %

Pump "E85" often tests well below 85% (roughly 51–83% depending on station and season). If you know the real content from a test kit or sensor, enter it — an E30 tune that isn't flex-fuel has little margin for guessing.

Fill the tank

Total fuel to end up with (gal)

Tip: pump the E85 in first, then top with pump gas so the two mix in the tank. Default 14.5 gal = 2017 Golf Alltrack tank.

Top up what's in the tank

Fuel already in tank (gal)

Its current blend (% ethanol)

Fill up to (gal)

Check a mix you pumped

E85 pumped (gal)

Pump gas pumped (gal)

Math assumes ethanol percentages by volume and that volumes add. Always confirm your tune's required blend and tolerances with your tuner.