Fleet vehicle gas mileage cost calculator: what your trucks and vans really spend on fuel
At the U.S. average gasoline price of $4.319 a gallon, a half-ton pickup rated at 19 mpg that covers 15,000 miles a year burns about $3,410 of fuel, or 22.7 cents a mile. Five of them cost about $17,050 a year. Diesel is $6.285 a gallon, 45.5% more, so a diesel van needs about 46% better mileage just to break even on fuel. This calculator takes your vehicle count, daily miles, mpg and fuel price, and returns fuel cost per year, per month, per mile, per service call and per billable hour.
Full-size vans and heavy-duty pickups have no EPA fuel economy rating. Vehicles over 8,500 lb gross vehicle weight rating are exempt from EPA testing, so the mpg defaults for those classes come from independent tests and owner reports, and are labelled that way below. Treat every default as a starting point and replace it with the mpg your own trucks log.
Who this is for
Owner-operators and office managers at US trade service businesses (HVAC, plumbing, electrical, landscaping, pest control) who run company vehicles and want to know what fuel costs per truck, per mile and per job. It is most useful for budgeting a fleet of 2 to 25 vehicles, for comparing what a pickup, a gasoline van and a diesel van would burn on the same routes, and for putting a defensible fuel number into a price or an hourly rate.
It is not built for businesses that reimburse technicians for personal vehicles at the IRS rate (multiply miles by the rate instead), for electric fleets (there is no electricity cost model here), for long-haul freight trucks, or for anyone who wants the full cost of owning a vehicle. Insurance, depreciation, maintenance, tires, tolls and registration are outside this calculator. Fuel is one line of a vehicle budget, and this page only prices that line.
What you will enter
Every input maps to a variable in the formula further down. In plain language:
- Vehicles (N)
- How many vehicles drive the same pattern. If your fleet mixes classes, run the calculator once per class and add the results.
- Miles per day (m) and working days (D)
- Miles one vehicle drives on a working day, and how many days a year it works. Together they give annual miles per vehicle, M = m × D. Use your logbook or telematics figure if you have one.
- Fuel economy (E)
- Miles per gallon your vehicle actually gets, loaded and in service. The class defaults are starting points; your own logged mpg is better.
- Fuel price (P)
- Dollars per gallon paid at the pump. The calculator pre-fills the EIA average for the region you pick, for gasoline and for diesel, and you can overwrite either.
- Idle hours (H_idle) and idle burn (R_idle)
- Hours a vehicle idles per working day, and the gallons it burns per idle hour. Optional. No default burn rate is assumed, because it depends on the engine and on whether the cab or a PTO load is running.
- Service calls (K) and billable hours (H_bill) per day
- Optional. They turn the daily fuel cost into fuel per service call and fuel per billable hour, the two numbers that feed a flat-rate price or an hourly rate.
Calculate your fuel cost
Estimates only, for informational purposes. This is not professional financial, legal or tax advice. Fuel prices move weekly and your mpg depends on load, route and driving; confirm figures against your own fuel card statements and logs.
The same routes in four vehicle classes
This table reuses your vehicle count, miles per day and working days from above, applies each class's default mpg and the fuel price for its fuel type, and leaves idling out so the classes compare like for like. The lowest cost per mile is highlighted. These are not equivalent vehicles: a half-ton pickup will not carry what a full-size van carries, so read the table as what each class's mpg and fuel type imply on the same mileage, not as advice to change vehicles.
| Vehicle class | Default mpg | Fuel price | Per vehicle, per year | Per mile | Fleet, per year |
|---|---|---|---|---|---|
| Enter vehicles, daily miles, working days and both fuel prices above to see the comparison. | |||||
What the class comparison shows
At the starting assumptions (5 vehicles, 60 miles a day, 250 days, U.S. average prices) the half-ton pickup is cheapest at about $3,410 per vehicle a year, or 22.7 cents a mile. The gasoline van costs about $4,320 (28.8 cents), the heavy-duty pickup about $4,630 (about 31 cents) and the diesel van about $4,710 (31.4 cents). The diesel van gets a third more miles per gallon than the gasoline van and still costs about $395 more per vehicle a year, because diesel costs 45.5% more per gallon.
That gap comes from prices, not from the vehicles. A 33% mpg edge would pay off only if diesel cost less than 33% more than gasoline per gallon. The EIA figures show why it does not: the U.S. average for diesel is $6.285 against $4.319 for gasoline, a premium of $1.97 a gallon, and diesel is up $2.546 on a year ago while gasoline is up $1.151. If you run diesel vehicles, the break-even is the number in the note above the table.
Worked example: five pickups, then what moves the bill
Take five half-ton pickups rated at 19 mpg. Each drives 60 miles a day for 250 days, which is 15,000 miles a year and 789 gallons. At the U.S. average gasoline price of $4.319 a gallon that is about $3,410 per pickup and $17,050 for the five, or $1,421 a month for the fleet.
- Per job. $3,410 over 250 days is $13.64 a day per pickup. At 4 service calls a day that is $3.41 of fuel per call, and at 5 billable hours a day it is $2.73 per billable hour. Both are illustrative: use your own calls and billable hours. Fuel per call is the figure to carry into the HVAC flat-rate margin calculator, and fuel per billable hour is a line you can add to overhead in the technician billable rate calculator.
- One more mpg. Going from 19 to 20 mpg saves 39 gallons a year per pickup, about $170, or $852 across the five. Two more mpg saves about $1,624 across the five.
- Fuel price. Every $0.50 a gallon moves the fleet's bill by about $1,974 a year. A $1.00 rise adds about $3,947.
- Region. The EIA's West Coast gasoline average is $5.467 and its Gulf Coast average is $3.852, a gap of $1.615 a gallon. On 789 gallons that is about $1,275 per pickup a year, or $6,375 for five. Against California's $5.827 the gap is $1.975 a gallon, about $1,559 per pickup. These are regional averages, and prices at a specific station can be well above or below them.
On fuel alone, the IRS's 76 cent business mileage rate is about three and a third times the 22.7 cents a mile in this example. The IRS rate covers the fixed and variable costs of operating a vehicle, not just fuel, so the two are not meant to match. It is shown in the results only for scale.
What changes your real cost
Five things move the total more than the vehicle's sticker mpg does. Only the first three are in the calculator.
- The mpg you actually get. Ratings are for tested conditions. A test of a rear-wheel-drive Transit with the EcoBoost engine reached about 14 to 15 mpg combined, and an all-wheel-drive high-roof crew version logged about 13 mpg combined, as reported by a Ford dealer citing Car and Driver. Shelving, tools and a full load cost mileage on top of that. A month of fill-ups divided into miles driven beats any default.
- The price per gallon you pay. Regional averages hide a wide spread. Diesel ranges from $6.027 on the Gulf Coast to $8.039 in California, a gap of more than $2 a gallon.
- Idling. Idle hours cost the burn rate times the fuel price. As an illustration only, a vehicle that burned 0.5 gallon per idle hour would spend $2.16 for each idle hour at $4.319. The calculator assumes no burn rate; enter the one from your telematics or the engine spec.
- Route and job mix. Miles between jobs, return trips for parts and how calls are batched change annual miles far more than driving style does. This calculator takes miles as an input rather than predicting them.
- What it leaves out. Fuel card discounts and rebates, diesel exhaust fluid, maintenance, tires, depreciation, insurance and tolls are not modeled, and neither are electric vehicles. For a hybrid, enter your own mpg.
Fuel prices used in the calculator
These are the EIA's weekly retail prices for the week of September 14, 2026, all taxes included, exactly as the region selector uses them. Diesel carries a premium over gasoline in every region, shown in the last column.
| Region | Gasoline, per gallon | Diesel, per gallon | Diesel premium |
|---|
Fuel economy defaults by vehicle class
Vehicles under 8,500 lb GVWR have EPA ratings. Full-size vans and heavy-duty pickups do not, so their defaults come from independent tests and owner data, and where sources disagree the note says so. Nothing here is a manufacturer's guarantee of mileage.
| Vehicle class | Default used | Range in sources | Basis | Notes |
|---|
Methodology and sources
For each vehicle class and fleet, the calculator returns fuel cost with this formula:
Annual miles per vehicle M = m × D
Driving fuel (gallons) G_drive = M ÷ E
Idling fuel (gallons) G_idle = H_idle × D × R_idle
Fuel cost per vehicle C_vehicle = (G_drive + G_idle) × P
Fleet fuel cost C_fleet = N × C_vehicle
Per month C_fleet ÷ 12
Per mile C_vehicle ÷ M
Per service call C_vehicle ÷ D ÷ K
Per billable hour C_vehicle ÷ D ÷ H_bill
Diesel break-even mpg E_diesel = E_gasoline × P_diesel ÷ P_gasoline
The first line turns daily miles and working days into annual miles. The second and third convert miles and idle hours into gallons. The fourth prices them at the fuel price for the vehicle's fuel type, and the fifth scales to the fleet. The last line is what makes the diesel note work: a diesel vehicle costs the same per mile as a gasoline one when its mpg is higher by exactly the ratio of the two prices.
This page's formula is a straightforward fuel-cost identity, not a proprietary model. The inputs and the defaults carry the uncertainty, which is why each one is editable and each default is labelled by source.
What it leaves out: fuel card discounts and rebates, sales or excise taxes beyond those already in the EIA price, diesel exhaust fluid, additives, maintenance, tires, depreciation, insurance, tolls, and electric or plug-in vehicles. The class comparison also leaves out idling.
Sources
| Data | Last checked | Basis | Source |
|---|
Fuel prices come from the EIA, a US government statistics agency, and the mileage rate from the IRS. Fuel economy defaults for classes without EPA ratings come from independent tests and owner reports, and the pickup range comes from dealer pages that cite EPA ratings; the official fueleconomy.gov tool was not used directly for those figures, so confirm your exact model there. Where a vendor or dealer page conflicts with an official source, the official source wins.
Note on the IRS rate: the IRS business standard mileage rate was 72.5 cents a mile from January 1 to June 30, 2026, and 76 cents from July 1 to December 31, 2026, after a mid-year increase the IRS tied to rising fuel costs.
Frequently asked questions
Why are some mpg defaults not EPA ratings?
The EPA rates only vehicles under 8,500 lb gross vehicle weight rating. Full-size vans such as the Ford Transit and Ram ProMaster, and heavy-duty pickups such as the F-250, are above that line and have no official mpg. For those classes the defaults are a midpoint of independent test results and owner reports: 15 mpg for a gasoline van, 20 mpg for a diesel van and 14 mpg for a heavy-duty gasoline pickup. The half-ton pickup default of 19 mpg sits inside the roughly 16 to 21 mpg range listed for 2026 F-150 gasoline models. Replace any default with your own logged mpg.
How do I find the real mpg of my trucks?
Fill the tank each time, record the odometer reading and the gallons added, and divide miles driven by gallons over several weeks. Fuel card statements plus odometer or telematics readings give the same answer with less effort. Average across a month or more, because a single tank is distorted by how full it was at the start and end. Do this per vehicle, since two identical trucks can differ if one carries more equipment or idles more.
Does diesel save money at current prices?
Not on fuel alone. At the EIA's September 14, 2026 prices, diesel is $6.285 a gallon against $4.319 for gasoline, so it costs 45.5% more. A diesel vehicle needs about 45.5% better mpg than a gasoline one to cost the same per mile. Against a 15 mpg gasoline van that is about 21.8 mpg, and the 20 mpg default for a diesel van falls short of it. Diesel can still make sense for towing, load or durability, and its purchase price, maintenance and diesel exhaust fluid are not part of this comparison.
Should I use the IRS mileage rate instead of fuel cost?
They answer different questions. The IRS business standard mileage rate is 76 cents a mile from July 1, 2026, up from 72.5 cents for January through June, and it is based on the fixed and variable costs of operating a vehicle, not just fuel. Fuel alone in the starting example is 22.7 cents a mile, about 30% of the IRS rate. The IRS rate is used for tax deductions and tax-free reimbursement of business miles. Whether it or actual expenses suits a particular vehicle is a tax question, so ask a tax professional.
How much does the region matter?
A lot. The EIA's West Coast gasoline average is $5.467 a gallon and the Gulf Coast average is $3.852, a gap of $1.615. On a pickup that burns 789 gallons a year that is about $1,275 per vehicle, or about $6,375 for five. California's $5.827 widens the gap to about $1,559 per vehicle. Regional averages also hide local variation, so overwrite the price with what your fuel card or local stations charge.
How much does idling cost?
Each idle hour costs the gallons burned per hour times the fuel price. As an illustration only, a vehicle that burned 0.5 gallon per idle hour would spend $2.16 per idle hour at $4.319 a gallon. The calculator does not assume a burn rate because it depends on the engine and on whether the cab or a power take-off is running. Enter the figure from your telematics or the engine specification, and the results show idling as its own share of the bill.
Does the calculator work for hybrids or electric vehicles?
Hybrids, yes: enter your own mpg. EPA lists the 2026 F-150 PowerBoost hybrid at about 23 to 25 mpg combined depending on drive type, according to Ford dealer pages. Electric vehicles are not modeled, because they need a cost per kilowatt-hour and miles per kilowatt-hour rather than a price per gallon.
Do the fuel prices update automatically?
No. They are a snapshot of the EIA's retail averages for the week of September 14, 2026, and the EIA publishes new figures weekly, with the next update scheduled for September 22, 2026. This page's last-updated date shows when the prices were last checked. Overwrite the gasoline and diesel fields whenever you want current or local prices. Changing the region refills both fields with the snapshot values.