What is the gas tax calculator — state & federal fuel tax cost?
In short
The federal gas tax is 18.4 cents per gallon (unchanged since 1993). State gas taxes range from 8.95¢/gal (Alaska) to 67¢/gal+ (Illinois). Combined, U.S. drivers pay an average of ~57¢/gal in fuel excise taxes — about $305/year at average driving levels.
This calculator shows how much you pay in state and federal fuel excise taxes each year based on your state's rate and your estimated annual fuel consumption.
How to use this calculator
- 1Enter your state gas tax rate in cents per gallon (find it on your state DMV or tax authority website).
- 2Enter your estimated annual gallons consumed (total miles ÷ average MPG; U.S. average is ~536 gal/yr).
- 3View your annual state tax, federal tax, and total gas tax cost.
The formula
- S
- — State rate (¢/gal)
- F
- — Federal rate = 18.4¢/gal
- G
- — Gallons per year
Worked example
The scenario
A California driver uses 536 gallons/year. CA state rate ≈ 59.6¢/gal.
The result
State tax = $319.46 · Federal tax = $98.62 · Total annual gas tax = $418.08.
Common use cases
- Compare fuel tax burden across states before relocating.
- Estimate annual fuel tax cost for budgeting.
- Understand how gas taxes affect the true cost of driving.
- Evaluate impact of fuel-efficient vehicles on tax cost.
Limitations & assumptions
- Does not include sales tax on gasoline (applicable in some states).
- State rates change periodically — verify current rate with your state DOT.
- Diesel rates differ from gasoline rates in most states.
- Diesel and alternative fuel vehicles may have different tax structures.
Frequently asked questions
Disclaimer: KalkWise calculators are provided for general informational and educational purposes only and do not constitute financial, investment, tax, or legal advice. Results are estimates based on the figures you enter and the assumptions described above. Actual outcomes will vary. Consult a qualified professional before making financial decisions.