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Washington Gas Cost Calculator
Regular gas in Washington averages $5.10 a gallon (EIA, week of 2 November 2026), down 11¢ from the week before. At that price a 100-mile drive in a 25 mpg car costs about $20.38 in fuel.
- Regular
- $5.10
- down 11¢ this week
- Midgrade
- $5.42
- down 9¢ this week
- Premium
- $5.63
- down 12¢ this week
- Diesel (region)
- $6.58
- down 4¢ this week
Fill the tank, reset the trip meter, drive, then fill up again: the second fill-up is the fuel used.
Washington average, week of 2 Nov 2026 (converted to US dollars per litre; type your own price in any currency).
each for people
Enter a fuel price to see the cost.
- Distance
- Fuel needed
- Fuel economy
Your gas mileage
- Miles per gallon (US)
- Litres per 100 km
- Kilometres per litre
- Fuel cost
Cost to drive in Washington at $5.10 a gallon
One-way fuel cost of common trip lengths with regular gas, for typical fuel economy.
| Distance | Small car33 mpg | Midsize car28 mpg | SUV24 mpg | Pickup truck19 mpg | Hybrid50 mpg |
|---|---|---|---|---|---|
| 25 miles | $3.86 | $4.55 | $5.31 | $6.70 | $2.55 |
| 50 miles | $7.72 | $9.10 | $10.61 | $13.41 | $5.10 |
| 100 miles | $15.44 | $18.20 | $21.23 | $26.82 | $10.19 |
| 200 miles | $30.88 | $36.39 | $42.46 | $53.63 | $20.38 |
| 300 miles | $46.32 | $54.59 | $63.69 | $80.45 | $30.57 |
| 500 miles | $77.20 | $90.98 | $106.15 | $134.08 | $50.95 |
| 1,000 miles | $154.39 | $181.96 | $212.29 | $268.16 | $101.90 |
About gas prices in Washington
- Regular gas in Washington is 94¢ a gallon above the US average of $4.15 this week.
- Premium usually costs 90¢ to $1 more a gallon than regular. Most cars run fine on regular; only use premium if your owner’s manual says it is required.
Washington sales tax calculator → Washington paycheck calculator →
Other states
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Prices: U.S. Energy Information Administration (EIA), Weekly Retail Gasoline and Diesel Prices, week of 2 November 2026, in dollars per gallon including taxes, updated every week. The EIA publishes nine states on their own; other states show their region’s average. Prices at your station will differ, and your real fuel economy depends on speed, traffic, load and weather, so treat the result as an estimate.
About the Gas Cost Calculator
The Gas Cost Calculator works out how much fuel a trip will use and what it will cost. Enter the distance, your car’s fuel economy and the gas price, tick round trip if you are coming back, and split the cost between the people in the car. The price starts from the latest weekly average published by the US Energy Information Administration, for regular, midgrade, premium or diesel, and every state has its own page with this week’s price. The Gas mileage tab works out your car’s real mpg from a fill-up, and the calculator also works in kilometres and litres per 100 km.
How to use it
- 1 Enter the one-way distance of your trip, and tick “Round trip” if you are driving back.
- 2 Enter your car’s fuel economy, or tap a vehicle type for a typical figure.
- 3 Keep this week’s average gas price, tap another fuel grade, or type the price at your station.
- 4 Enter how many people are sharing the cost, then read the total and the cost per person.
Frequently asked questions
How much is gas in Washington?
In the week of 2 November 2026, the EIA’s average prices in Washington were: Regular $5.10, Midgrade $5.42, Premium $5.63 and Diesel $6.58 a gallon. Prices are updated every week.
How much does it cost to drive 100 miles in Washington?
About $20.38 in a car that gets 25 miles per gallon: 100 ÷ 25 = 4 gallons at $5.10. A 50 mpg hybrid would spend $10.19, and a pickup truck at 19 mpg about $26.82.
How much does a 500-mile road trip cost in gas in Washington?
At $5.10 a gallon, 500 miles costs about $101.90 in a 25 mpg car (20 gallons). Double it for the drive home, or tick “Round trip” in the calculator.
How do I calculate the gas cost of a trip?
Divide the distance by your car’s miles per gallon to get the gallons you need, then multiply by the price per gallon. A 300-mile trip in a 30 mpg car uses 10 gallons; at $3.50 a gallon that is $35.
How much gas does it take to drive 100 miles?
It depends on fuel economy: 4 gallons at 25 mpg, about 3.3 gallons at 30 mpg and 2 gallons in a 50 mpg hybrid. Multiply by the gas price for the cost.
How do I work out my car’s gas mileage?
Fill the tank and reset the trip meter. Drive as normal, then fill up again and note the gallons. Divide the miles on the trip meter by those gallons: 320 miles on 11.2 gallons is 28.6 mpg. Use the Gas mileage tab to do it for you.
How do I convert mpg to L/100 km?
Divide 235.21 by the mpg (US gallons). 30 mpg is 7.8 L/100 km, and 8 L/100 km is 29.4 mpg. The calculator converts automatically when you switch units.
How do I split gas money for a road trip?
Work out the total fuel cost for the whole trip, including the drive back, and divide by the number of people in the car. Some groups leave the driver out of the split as thanks for driving.
How often are the gas prices updated?
Every week. The EIA surveys gas stations every Monday and publishes national, regional and state averages the same day; the calculator picks them up on Tuesday.
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