Fuel Cost Calculator · Practical guide
Monthly Commute Gas Cost Calculator
Multiply your round-trip miles by workdays, divide by MPG, times the gas price — a 40-mile commute runs about $123 a month.
At a glance
The Short Answer
Monthly commute gas cost is round-trip miles × workdays ÷ MPG × gas price. A 40-mile round trip, 22 workdays a month, at 25 MPG and $3.50 per gallon comes to $123.20 per month. Enter the full monthly mileage in the calculator above to see your exact cost and per-mile rate.
Interactive tool
Fuel Cost Calculator
Enter your own values, then compare the result with the examples below.
Fuel Cost Results
Monthly Cost by Commute Length
Assuming 22 workdays, 25 MPG, and gas at $3.50 per gallon:
| Round-Trip Commute | Monthly Miles | Gallons | Monthly Gas Cost |
|---|---|---|---|
| 20 miles | 440 | 17.6 | $61.60 |
| 40 miles | 880 | 35.2 | $123.20 |
| 60 miles | 1,320 | 52.8 | $184.80 |
The Annual View Is Eye-Opening
Multiply the monthly figure by 12: that 40-mile commute costs about $1,478 per year in gas alone. Over a five-year stretch at the same job, fuel for commuting tops $7,000 — before counting wear, tires, oil changes, and depreciation, which typically double the true cost per mile.
How Vehicle Choice Compounds
On an 880-mile monthly commute, swapping a 20 MPG vehicle ($154.00/month) for a 35 MPG one ($88.00/month) saves $66 per month — nearly $800 per year. Long commutes are where fuel economy differences hit hardest.
Ways to Shrink the Bill
- Carpool with one coworker and the per-person cost drops by half.
- Negotiate one remote day per week — a 20% cut in commute miles is a 20% cut in gas.
- Keep tires inflated and skip aggressive acceleration; both measurably improve real-world MPG in stop-and-go traffic.
Frequently Asked Questions
Should I count only workdays?
For a pure commute figure, yes — typically 20 to 23 workdays per month. Add errands and weekend driving separately if you want your total monthly fuel budget.
Does rush-hour traffic change the estimate?
Yes. Idling and stop-and-go driving can drop your effective MPG by 15-30% versus the highway rating, so use your observed commute MPG rather than the window-sticker number.
Can I deduct commute gas on my taxes?
Regular commuting between home and a main workplace is not deductible for employees. Self-employed workers may deduct business miles driven between work sites.
How do I compare commuting by car vs transit?
Compare the monthly gas figure against the transit pass price, then add parking and tolls to the driving side. The calculator's cost-per-mile output makes the comparison direct.