When should you buy gas? For most drivers, the answer is simply whenever the tank is running low.
But now that high gas prices are routine, it may be worth your while to fill up strategically on the days when fuel costs are cheapest. According to a new study from GasBuddy, a gas price comparison app, Monday is the best day of the week to buy gas.
On average, Monday was the cheapest day for gas prices around the country in 2021. The beginning of the work week also saw the lowest gas prices in several previous years. Friday, which has traditionally been one of the more expensive days for gas prices with the start of the weekend, was surprisingly the second least-expensive day to fill up in 2021.
“Though there is variation in daily gas prices across different states, the consensus is that filling up at the beginning or end of the work week, on Monday or Friday, is the best way to save money," Patrick De Haan, head of petroleum analysis at GasBuddy, said in a news release accompanying the data.
Cheapest day for gas prices: How much will you really save?
How much money you can realistically save on gas by filling up on one day or another will vary widely. The answer depends not just on the difference in gas prices but also what kind of vehicle you drive (and its gas mileage), as well as how much you drive over the course of a typical month or year.
And, of course, whether you save anything at all depends on the idea that the day you fill up will actually have cheaper gas prices — and this is impossible to predict in any given week.
GasBuddy estimates that drivers can typically save $50 to $100 per year by filling up on the cheapest days of the week. That's based on gas costing roughly $3.35 per gallon, with four monthly fill-ups of 12 gallons each, and with gas running 7 cents to 12 cents per gallon more expensive on other days of the week.
The gist is that you'll save maybe 2% to 4% on gas if you fill up strategically (or just happen to get lucky) by hitting the gas station on the cheapest day of the week.
All things considered, it can't hurt to try to gas up when prices are lowest. But with all the uncertainties and the fact that the maximum savings isn't overwhelming, you shouldn't feel bad if you simply fill up whenever you need to.
It's arguably just as important or more to employ other time-tested strategies to save on gas, like these recommended by AAA. They include practicing good driving habits — avoid idling and quick starts and stops, use cruise control and stick to the speed limit — and buying a car with good fuel economy in the first place.
You may also want to use a credit card with good rewards for gas station purchases. Some cards will give you 3% or even 5% cash back every time you fill up the tank.