Is It Worth Driving to a Cheaper Gas Station?

By SimpleTools24Published 7 October 20264 min read

Driving to a cheaper gas station is worth it only when the money saved on the fill-up is more than the cost of the extra fuel the detour uses. Calculate the saving (price difference × amount you'll buy), then the detour cost (extra round-trip distance ÷ fuel economy × fuel price). If the saving is bigger, go; if not, fill up nearby. Small price differences rarely justify more than a few extra miles or kilometres, especially if you're only buying a little fuel.

In this guide

The Break-Even Formula

The two numbers to compare
Calculation	Formula
Saving at the cheaper station	(nearby price − cheaper price) × fuel you'll buy
Cost of the detour	extra round-trip distance ÷ fuel economy × cheaper price
Net result	saving − detour cost

Use the round-trip extra distance: getting there and getting back to your route. People often count only one way.

Worked Example in Gallons

Nearby price: $3.59/gal; cheaper station: $3.45/gal (14 cents less)
Buying: 12 gallons
Extra round trip: 6 miles
Car: 28 MPG

Saving: $0.14 × 12 = $1.68
Detour fuel: 6 ÷ 28 = 0.214 gallons
Detour cost: 0.214 × $3.45 = $0.74
Net: $1.68 − $0.74 = $0.94 saved

Worth it, but barely. Is under a dollar worth ten extra minutes? That's your call.

Worked Example in Litres

Nearby: 1.82 per litre; cheaper: 1.76 (6 cents less)
Buying: 40 litres
Extra round trip: 12 km
Car: 7 L/100 km

Saving: 0.06 × 40 = 2.40
Detour fuel: 12 × 7 ÷ 100 = 0.84 litres
Detour cost: 0.84 × 1.76 = 1.48
Net: 0.92 saved

Again worthwhile, but only just.

How Far Can You Drive for a Given Saving?

Rearranging the formula gives the maximum extra round-trip distance before the detour wipes out the saving:

text

max extra distance = (price difference × fuel bought × fuel economy) ÷ cheaper price

Using the first example: (0.14 × 12 × 28) ÷ 3.45 ≈ 13.6 miles round trip. Beyond that, you lose money.

Two factors increase the break-even distance: buying more fuel (a full tank of a large vehicle) and having better fuel economy. Small fill-ups in thirsty vehicles rarely justify a detour.

Costs People Forget

The fuel maths is only part of the picture:

Your time. Ten extra minutes for a one-dollar saving is a poor hourly rate.
Wear and running costs. Tyres, maintenance and depreciation all increase with distance. Some people add a small per-mile figure to the detour cost.
Queues. Cheap stations are often busy.
Stop-start traffic. A detour through town uses more fuel than the same distance on an open road.

When a Detour Clearly Makes Sense

The cheaper station is on a route you're already driving, so the extra distance is near zero.
You're filling a large tank and the price gap is significant.
You'll pass it anyway within a day or two and have enough fuel to wait.

Combining the fill-up with an existing trip is usually the best of both worlds. Planning and combining trips is one of the habits covered in how to save money on fuel.

Loyalty Programmes and Discounts

Supermarket fuel discounts, loyalty points and card cashback change the effective price. Use the price you actually pay after discounts in the formula, and be honest about the value of points you may never redeem.

Check It in Seconds

The fuel savings calculator includes a cheaper-station check: enter the nearby and cheaper prices, how much you'll buy, the extra round-trip distance and your fuel economy (MPG, L/100 km or km/L), and it shows the saving, the detour cost and the net result. If you'd like to understand the underlying cost formula, see how to calculate fuel cost.

Quick Reference: Break-Even Distances

Using the formula above for a car averaging 30 MPG and fuel around $3.50 a gallon, the maximum extra round trip before the detour stops paying off is roughly:

Approximate break-even extra round-trip distance (30 MPG, about $3.50/gal)
Price difference	Buying 8 gallons	Buying 15 gallons
5 cents	about 3 miles	about 6 miles
10 cents	about 7 miles	about 13 miles
20 cents	about 14 miles	about 26 miles

These are break-even points, where you save nothing; a worthwhile detour needs to be well inside them. Your own figures will differ with fuel economy and price, which is why it's worth running the numbers for your car.

The Bigger Picture

Chasing small price differences tends to save far less than steady habits. Driving a little more smoothly, keeping tyres at the right pressure and combining trips reduce the fuel you use on every journey, not just at the pump. If you fill up often, though, choosing the cheaper of two stations on your normal route adds up over a year with no detour at all.

Frequently Asked Questions

How many miles is it worth driving for cheaper gas?

It depends on the price gap, the amount you buy and your fuel economy. For a 10 to 15 cent gap on a typical fill-up, the break-even is often only a few miles round trip.

Does it matter how much fuel I buy?

Yes. The saving scales with the amount, while the detour cost doesn't, so bigger fill-ups justify longer detours.

Should I count the trip back?

Yes. Use the extra round-trip distance, not just the distance to the station.

Are price-comparison apps accurate?

They depend on recent reports. Prices can change, so check the timestamp before making a special trip.

Summary

Compare the fill-up saving with the detour's fuel cost using the round-trip distance. Small price gaps only justify short detours, and the best saving is a cheaper station on a route you're already driving.