What is the gas tax in South Carolina?

South Carolina charges a motor fuel user fee of 28.75 cents per gallon on gasoline, fully phased in after a series of two-cent annual increases that ended in 2022. This excise funds road and bridge maintenance across the state.

How much total tax is in a gallon of South Carolina gas?

Each gallon carries the 28.75-cent South Carolina excise plus the 18.4-cent federal gasoline excise, for roughly 47.15 cents of tax per gallon before any local or environmental fees. This tool sums both to show your total fuel tax.

How do I figure my gas tax per mile?

Divide the per-gallon tax by your vehicle's miles-per-gallon. At 47.15 cents per gallon and 30 MPG, you pay about 1.57 cents of fuel tax per mile. Enter your MPG and miles to see your annual fuel tax burden.

Does South Carolina tax diesel differently?

Diesel is taxed at the same 28.75-cent state user fee per gallon as gasoline in South Carolina, though the federal diesel excise is higher at 24.4 cents. This calculator uses gasoline rates; adjust the federal figure if you run on diesel.

Is the gas tax included in the pump price?

Yes. Both the state and federal fuel taxes are baked into the per-gallon price you see at the pump, so you never pay them separately. This tool isolates how much of your spending is actually tax versus the cost of the fuel itself.

South Carolina Gas Tax Calculator

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South Carolina charges a 28.75-cent-per-gallon motor fuel user fee on gasoline, fully phased in after annual two-cent increases ended in 2022. Added to the 18.4-cent federal excise, every gallon carries about 47.15 cents of tax. This tool turns that into a per-tank, per-mile, or annual figure.

How it works

You can estimate from a single tank or from annual mileage and MPG:

gallons (mileage mode) = annual miles ÷ MPG
state tax  = gallons × $0.2875
federal tax = gallons × $0.184
total tax   = gallons × ($0.2875 + $0.184)

The per-mile tax is simply the combined per-gallon rate divided by your MPG, so a more efficient car pays less fuel tax per mile. Both taxes are already built into the pump price.

Example and notes

Driving 12,000 miles a year at 30 MPG burns 12,000 ÷ 30 = 400 gallons. The state fuel tax is 400 × 0.2875 = 115 dollars, the federal is 400 × 0.184 = 73.60 dollars, for about 188.60 dollars in annual fuel taxes. Diesel uses the same 28.75-cent state rate but a higher 24.4-cent federal rate. Rates can change by legislation, so confirm the current motor fuel user fee with the SC Department of Revenue.