Is it worth driving further to save on gas?

Usually not. To save money driving 5 miles out of your way for gas that's $0.10 cheaper, you'd need to buy 15+ gallons just to break even. For most fill-ups, driving even a few miles extra costs more in gas than you save.

How do I calculate if cheaper gas is worth the drive?

Use this formula: (Extra miles × Your car's MPG cost) vs. (Price difference × Gallons purchased). If the extra driving cost exceeds your savings, it's not worth it. A 10-mile round trip at 25 MPG with $3.50 gas costs $1.40—you'd need to save more than that.

How much cheaper does gas need to be to drive 5 miles?

For a typical 12-gallon fill-up with a car getting 25 MPG and gas at $3.50, driving 5 extra miles costs about $0.70. You'd need gas to be at least $0.06/gallon cheaper just to break even. Any less savings and you're losing money.

What about time—is my time worth anything?

Yes. If you value your time at even $15/hour, a 10-minute detour 'costs' $2.50 in time. Add that to actual fuel cost, and that $0.10/gallon savings almost never makes sense unless you're filling a large tank.

Is Driving Further for Cheaper Gas Worth It? Do the Math

You spot a gas station 5 miles away advertising gas that’s $0.15 cheaper per gallon. Worth the drive? Let’s do the actual math—because the answer is usually “no.”

The Quick Answer

For most situations, driving out of your way for cheaper gas costs more than you save.

Extra Distance	Typical Break-Even Savings Needed
2 miles round trip	~$0.03/gallon
5 miles round trip	~$0.06/gallon
10 miles round trip	~$0.12/gallon
20 miles round trip	~$0.25/gallon

Based on 12-gallon fill-up, 25 MPG car, $3.50/gallon gas

The Formula

Cost of Driving to Cheaper Gas

Extra fuel cost = (Round-trip miles ÷ Your MPG) × Gas price

Your Savings

Gas savings = Price difference per gallon × Gallons you're buying

Is It Worth It?

If Extra fuel cost > Gas savings → Don’t do it

Real Examples

Example 1: 5 Miles for $0.10 Cheaper

Factor	Value
Your car’s MPG	25 mpg
Current gas price	$3.50/gallon
Cheaper station price	$3.40/gallon
Extra distance (round trip)	10 miles
Gallons to fill	12 gallons

Calculation:

Step	Math
Fuel used for detour	10 miles ÷ 25 MPG = 0.4 gallons
Cost of that fuel	0.4 × $3.50 = $1.40
Savings from cheaper gas	$0.10 × 12 gallons = $1.20
Net result	Lost $0.20

You actually lose money driving 5 miles for $0.10/gallon savings.

Example 2: 2 Miles for $0.15 Cheaper

Factor	Value
Your car’s MPG	30 mpg
Current gas price	$3.50/gallon
Cheaper station price	$3.35/gallon
Extra distance (round trip)	4 miles
Gallons to fill	14 gallons

Calculation:

Step	Math
Fuel used for detour	4 miles ÷ 30 MPG = 0.13 gallons
Cost of that fuel	0.13 × $3.50 = $0.47
Savings from cheaper gas	$0.15 × 14 gallons = $2.10
Net result	Saved $1.63

This one is worth it—short detour, bigger savings, larger fill-up.

Example 3: Costco 8 Miles Away, $0.25 Cheaper

Factor	Value
Your car’s MPG	28 mpg
Current gas price	$3.60/gallon
Costco price	$3.35/gallon
Extra distance (round trip)	16 miles
Gallons to fill	15 gallons

Calculation:

Step	Math
Fuel used for detour	16 miles ÷ 28 MPG = 0.57 gallons
Cost of that fuel	0.57 × $3.60 = $2.06
Savings from cheaper gas	$0.25 × 15 gallons = $3.75
Net result	Saved $1.69

Worth it—but only because the price difference is large and you’re filling a big tank.

Quick Reference Tables

Break-Even Price Difference Needed

How much cheaper gas needs to be to justify the drive (12-gallon fill-up, 25 MPG)

Round Trip Miles	At $3.00 Gas	At $3.50 Gas	At $4.00 Gas
2 miles	$0.02/gal	$0.02/gal	$0.03/gal
4 miles	$0.04/gal	$0.05/gal	$0.05/gal
6 miles	$0.06/gal	$0.07/gal	$0.08/gal
10 miles	$0.10/gal	$0.12/gal	$0.13/gal
15 miles	$0.15/gal	$0.18/gal	$0.20/gal
20 miles	$0.20/gal	$0.23/gal	$0.27/gal

Impact of Tank Size

10-mile round trip, 25 MPG, $3.50 gas—savings needed to break even

Gallons Purchased	Break-Even Savings
8 gallons	$0.18/gallon
10 gallons	$0.14/gallon
12 gallons	$0.12/gallon
15 gallons	$0.09/gallon
20 gallons	$0.07/gallon

Larger fill-ups make detours more worthwhile.

Impact of Your Car’s MPG

10-mile round trip, $3.50 gas, 12-gallon fill—break-even savings needed

Your MPG	Break-Even Savings
15 MPG (truck/SUV)	$0.19/gallon
20 MPG	$0.15/gallon
25 MPG	$0.12/gallon
30 MPG	$0.10/gallon
40 MPG (hybrid)	$0.07/gallon
50 MPG (hybrid)	$0.06/gallon

Better MPG cars can justify longer drives for cheaper gas.

Don’t Forget: Your Time Has Value

Adding Time Cost

If you value your time at $15/hour:

Extra Time	Time “Cost”
5 minutes	$1.25
10 minutes	$2.50
15 minutes	$3.75
20 minutes	$5.00

Full Cost Calculation

Factor	Example Value
Fuel cost of detour	$1.40
Time cost (10 min at $15/hr)	$2.50
Total cost	$3.90
Savings ($0.10 × 12 gal)	$1.20
Net loss	-$2.70

When you factor in time, driving for cheaper gas almost never makes sense.

When It IS Worth It

Scenarios Where Cheaper Gas Wins

Situation	Why It Works
On your existing route	Zero extra miles or time
Large tank (15+ gallons)	More gallons = more savings
Significant price difference ($0.25+)	Overcomes driving cost
Efficient car (35+ MPG)	Lower cost to drive there
Combined trip	Already going that direction

The Best Strategy

Do This	Instead of This
Fill up at cheap stations when passing by	Driving out of your way for gas
Use gas price apps to find cheap gas on your route	Dedicated gas station trips
Fill up when near cheap areas	Emergency fill-ups at expensive stations
Plan grocery + gas at same location	Separate trips

Gas Price Apps

Use these to find cheap gas on routes you’re already taking:

App	Features
GasBuddy	Price reports, trip cost calculator
Waze	Shows gas prices along your route
Google Maps	Displays gas prices near you
Gas Guru	Clean interface, price tracking

Use these to find cheap gas where you already are—not to plan special trips.

The Psychology Problem

Why We Drive for Cheaper Gas

Mental Trap	Reality
“I’m saving $1.80!”	But you spent $1.40 in gas getting there
“$0.15 cheaper feels significant”	On 12 gallons that’s only $1.80 total
“I see the savings at the pump”	You don’t see the gas burned getting there
“The big station must be ripping me off”	Maybe $1-2 difference on a full tank

What Actually Matters

Bigger Impact	Savings
Driving less overall	$50-200/month
Maintaining tire pressure	3% better MPG
Steady speed (no jack-rabbit starts)	5-10% better MPG
Combining trips	Multiple fill-ups of savings

Quick Decision Tool

Should You Drive Further for Gas?

Answer these:

Is the cheaper station on your existing route? → Yes? Go for it
Extra distance more than 5 miles round trip? → Probably not worth it
Price difference less than $0.10/gallon? → Almost never worth it
Filling less than 10 gallons? → Usually not worth it
Driving a gas-guzzler (under 20 MPG)? → Definitely not worth it

Rule of Thumb

If you have to think about whether it’s worth it, it probably isn’t.

The exception: If the cheap gas is at a store you’re already visiting (Costco, grocery store gas station), fill up there.

The Bottom Line

Key Takeaway	Remember
Driving extra miles burns gas	Often more than you save
Small price differences don’t matter	$0.05/gal = $0.60 on 12 gallons
Time has value too	10 minutes = $2.50 if time = $15/hr
Best strategy	Buy cheap gas when you happen to pass it
Stop obsessing	Focus on driving less overall

The $2 you might save driving across town for gas is wiped out by: the gas to get there, your time, wear on your car, and the mental energy of planning around gas prices.

Fill up at reasonably priced stations on routes you’re already taking. That’s it.