Trip cost worksheet
Diesel Fuel Cost Calculator
Estimate diesel fuel cost for a trip using distance, MPG, price per gallon, and optional fuel surcharge.
Maintained by Austin Witherow · Updated
Estimated trip fuel cost
$139.56
- Gallons needed
- 22.22
- Base fuel cost
- $139.56
- Fuel surcharge
- $0.00
Formula
Gallons needed = Trip distance ÷ MPGBase fuel cost = Gallons needed × Diesel price per gallonFuel surcharge = Base fuel cost × (Fuel surcharge % ÷ 100)Total fuel cost = Base fuel cost + Fuel surcharge Example: 400 miles at 18 MPG and $6.28 per gallon with no surcharge: 400 ÷ 18 = 22.22 gallons; 22.22 × $6.28 = $139.56 total.
Key caveat
The estimate assumes constant MPG and one constant price across the whole trip; real fuel economy moves with load, terrain, speed, weather, and traffic.
What this calculator is for
What will the diesel cost for this trip? Enter the distance, your vehicle's real miles per gallon, the price per gallon, and an optional fuel surcharge, and this diesel fuel cost calculator breaks the trip into gallons needed, base fuel cost, the surcharge, and the total. The default price is the U.S. national average from the EIA weekly on-highway diesel survey — dated below, and yours to override with the price at your pump or your state's figure from the regional table.
How it works
You enter total trip distance in miles and your vehicle's expected fuel economy in miles per gallon (MPG). The calculator divides distance by MPG to estimate how many gallons of diesel the trip will burn.
You enter a diesel price per gallon. The default is the EIA national weekly average (dated in the Sources section); replace it with your local pump price or your state's regional figure for a closer estimate.
The calculator multiplies gallons needed by price per gallon to compute the base fuel cost — the amount you would pay at the pump with no surcharge.
If you enter a fuel surcharge percentage, the tool applies that rate on top of the base fuel cost: surcharge = base fuel cost × (fuel surcharge % ÷ 100). This is common in freight and service contracts to offset volatile diesel prices.
Finally, it adds the surcharge to the base fuel cost to get the total estimated fuel cost for the trip and reports all four numbers: gallons needed, base fuel cost, surcharge, and total.
All calculations assume a constant MPG and price across the trip, which makes the estimate easy to interpret and compare across routes or vehicles.
Quick calculator insights
The prefilled price is a dated national average
The default price per gallon is the U.S. national average from the EIA weekly on-highway diesel survey — $6.276 for the week of October 19, 2026, including all taxes. It is a user-editable starting point, not a live feed, and regional averages that same week ranged from about $5.74 (Lower Atlantic) to $8.24 (California).
- EIA weekly survey
- Week of 2026-10-19 (released 2026-10-20)
- Includes all taxes
- Regions vary by over $2 per gallon in the same week
What a fuel surcharge actually does
A fuel surcharge is a percentage added on top of the base fuel cost to offset volatile diesel prices — common in freight, delivery, and service contracts. At 10%, the surcharge on the $483.08 base is $48.31 and the customer's total becomes $531.38 (the exact figures are $483.0769 × 1.10). The surcharge applies to the fuel cost, not to the whole job price, unless your contract says otherwise.
- Surcharge formula
- Base fuel cost × rate %
- Planned
- A dedicated fuel-surcharge calculator page for contract-style formulas
Cost per mile, by hand
Divide the total fuel cost by the trip distance: $531.38 over 500 miles is about $1.06 per mile. That figure is fuel-only — it excludes the driver, maintenance, insurance, permits, and tolls, so it is a floor for a quote, not a rate.
- Fuel-only cost per mile
- Total fuel cost ÷ distance
- Not a freight rate
- Add driver, maintenance, insurance, and tolls before quoting
Regional on-highway diesel prices, week of October 19, 2026
| Region | Price per gallon (incl. taxes) | vs. U.S. average |
|---|---|---|
| U.S. average | $6.276 | — |
| Lower Atlantic (PADD 1C) | $5.740 | −$0.54 |
| Gulf Coast (PADD 3) | $5.903 | −$0.37 |
| East Coast (PADD 1) | $5.984 | −$0.29 |
| Midwest (PADD 2) | $6.352 | +$0.08 |
| Rocky Mountain (PADD 4) | $6.422 | +$0.15 |
| New England (PADD 1A) | $6.470 | +$0.19 |
| Central Atlantic (PADD 1B) | $6.508 | +$0.23 |
| West Coast less California (PADD 5) | $6.659 | +$0.38 |
| West Coast (PADD 5) | $7.394 | +$1.12 |
| California | $8.242 | +$1.97 |
What a surcharge percentage adds (500 miles at 6.5 MPG, $6.28/gal)
| Fuel surcharge % | Base fuel cost | Surcharge added | Total fuel cost |
|---|---|---|---|
| 0% | $483.08 | $0.00 | $483.08 |
| 5% | $483.08 | $24.15 | $507.23 |
| 10% | $483.08 | $48.31 | $531.38 |
| 15% | $483.08 | $72.46 | $555.54 |
| 20% | $483.08 | $96.62 | $579.69 |
How to use this calculator
- 01Enter the total distance you plan to drive in miles. If your route has multiple legs, sum them or run each leg as its own scenario.
- 02Enter your vehicle's expected miles per gallon under the conditions you anticipate — your own measured MPG from fill-ups or the trip computer is the most accurate source.
- 03Enter the diesel price per gallon you expect to pay. The EIA national average is prefilled as a dated default; local prices vary widely by state.
- 04Add a fuel surcharge percentage if your contract or quote includes one; leave it at 0 for a plain pump-price estimate.
- 05Review gallons needed, base fuel cost, the surcharge, and the total. Divide the total by the distance for a fuel-only cost per mile if you are quoting a job.
Inputs explained
- Trip distance (miles)
- The total one-way miles you plan to drive. For a round trip, enter the doubled distance — the calculator prices one continuous distance, not separate legs.
- Miles per gallon (MPG)
- Your vehicle's diesel fuel economy under trip conditions. Your own measured figure (miles driven ÷ gallons to refill) beats any catalog rating, because load, terrain, speed, and wind shift the real number. The value must be greater than zero — a zero or negative MPG is rejected with an error message before any result is shown.
- Diesel price per gallon
- The price you expect to pay per gallon. The prefilled default is the EIA weekly national on-highway average (dated in the Sources section), which includes all taxes. State and regional averages vary widely — see the regional price table below.
- Fuel surcharge (%)
- An optional percentage applied on top of the base fuel cost, as freight and service contracts commonly do. Leave at 0 if you only need the pump cost.
Outputs explained
- Gallons needed
- Trip distance ÷ MPG — the diesel the trip will burn, assuming constant fuel economy.
- Base fuel cost
- Gallons needed × price per gallon — the pump cost with no surcharge.
- Fuel surcharge
- Base fuel cost × (surcharge % ÷ 100) — the add-on a contract applies to cover fuel price volatility.
- Total fuel cost
- Base fuel cost + fuel surcharge — the full estimated fuel bill for the trip.
Worked examples
Example 1: A 400-mile drive at 18 MPG
- Distance = 400 miles, MPG = 18, price = $6.28 per gallon (the EIA national average prefilled), surcharge = 0%.
- Gallons needed = 400 ÷ 18 = 22.2222 gallons.
- Base fuel cost = 22.2222 × $6.28 = $139.56; no surcharge applies.
- Total fuel cost = $139.56. Fuel-only cost per mile = $139.56 ÷ 400 ≈ $0.35.
Example 2: Box truck, 500 miles with a 10% fuel surcharge
- Distance = 500 miles, MPG = 6.5, price = $6.28 per gallon, surcharge = 10%.
- Gallons needed = 500 ÷ 6.5 = 76.9231 gallons.
- Base fuel cost = 76.9231 × $6.28 = $483.08.
- Fuel surcharge = the exact base × 10% = $483.0769 × 0.10 = $48.31.
- Total fuel cost = $483.0769 × 1.10 = $531.38 — about $1.06 per mile fuel-only.
Example 3: Pickup towing, 250 miles
- Distance = 250 miles, MPG = 16 (towing drops a diesel pickup's economy), price = $6.28 per gallon, no surcharge.
- Gallons needed = 250 ÷ 16 = 15.63 gallons.
- Base fuel cost = 15.63 × $6.28 = $98.13; total = $98.13.
- Fuel-only cost per mile = $98.13 ÷ 250 ≈ $0.39.
When to use it
- Budgeting the fuel for a road trip, a delivery run, or a towing job before you commit to the route.
- Pricing a freight or service job: the total divided by the distance gives a fuel-only cost per mile you can mark up from.
- Comparing vehicles or routes: run the same distance at different MPG figures to see how much economy is worth in dollars.
- Applying a contractual fuel surcharge percentage to a trip's base fuel cost.
- Checking how far a state's diesel price moves the bill by swapping regional prices into the same trip.
Tips
- Your real MPG is the number that matters most: measure it once from fill-ups (miles between fills ÷ gallons) and reuse it.
- For a round trip, double the distance. The calculator prices one continuous distance and does not add a return leg automatically.
- When quoting a per-mile rate, divide the total fuel cost by the trip distance — and remember the result is fuel-only; it excludes the driver, maintenance, insurance, and tolls.
- Regional diesel prices differ by more than a dollar a gallon in the same week; pick your region from the table below instead of the national average when the trip stays local.
- A fuel surcharge is a percentage of the base fuel cost, not of the total: 10% on a $483.08 base is $48.31, and the exact total is $531.38 ($483.0769 × 1.10).
Limitations
- The estimate assumes constant MPG and one constant price across the whole trip; real fuel economy moves with load, terrain, speed, weather, and traffic.
- The calculator prices a single continuous distance: no round-trip toggle, no multiple legs, and no mid-trip fill-up scheduling. Double the distance for a round trip; price extra legs as separate runs and add them yourself.
- There is no built-in cost-per-mile output: divide the total by the distance by hand. That figure is fuel-only — it is not a full freight rate.
- MPG figures by vehicle class are deliberately not listed here: published class ranges vary and were not verified against a primary source for this page. Use your own measured MPG.
- Zero or negative MPG is rejected with an error message ('Miles per gallon (MPG) must be greater than 0.') before a result is shown; enter your vehicle's real MPG.
- The default price is a dated weekly national average, not a live feed: diesel prices move weekly (and locally) — check the price at your pump or the EIA update before quoting.
- The surcharge here is a simple percentage of the base fuel cost. Contract surcharge formulas can work from a baseline price, mileage bands, or index-linked tables — the EIA also publishes guidance on how surcharges are commonly calculated.
Calculator guide
Use this diesel fuel cost calculator to estimate trip gallons, base fuel cost, a fuel surcharge, and the total diesel bill from distance, MPG, and price per gallon.
Enter trip distance, real MPG, the pump price (EIA weekly average prefilled), and an optional surcharge percentage to price a diesel trip.
Compare regional diesel prices from the EIA weekly survey and turn the trip total into a fuel-only cost per mile for quoting.
Methodology & assumptions
- The engine is four exact operations on your inputs: gallons = distance ÷ MPG; base = gallons × price; surcharge = base × (rate% ÷ 100); total = base + surcharge. Worked examples are asserted against the engine by an automated test (src/lib/__tests__/diesel-fuel-cost.test.ts).
- The prefilled price ($6.28) is the U.S. on-highway average from the EIA Gasoline and Diesel Fuel Update for the week of October 19, 2026 (released October 20, 2026), which states that prices include all taxes; it was read directly from the EIA page on 2026-10-24 and is a user-editable default, not a live feed.
- The regional price table is transcribed from the same EIA weekly release (PADD regions and California), with differences against the national average computed.
- Cost-per-mile figures in the examples are computed by hand as total ÷ distance and labeled fuel-only; the engine has no per-mile output (noted in the limitations as a planned engine change).
- MPG-by-vehicle-class tables are deliberately excluded: no primary source for class figures was read for this page, so the copy points to the user's own measured MPG instead.
- Surcharge handling is a straight percentage of the base fuel cost, matching the engine; contract-style surcharge formulas (baseline prices, index-linked rates) are out of scope and flagged for a dedicated surcharge calculator page.
Sources
Last reviewed 2026-10-24
- U.S. Energy Information Administration: Gasoline and Diesel Fuel Update
Weekly on-highway diesel prices (U.S. $6.276 and regional PADD figures for the week of 2026-10-19, released 2026-10-20; prices include all taxes). Read directly 2026-10-24. Source of the prefilled default and the regional table.
FAQs
How do I calculate the diesel fuel cost for a trip?+
Divide the trip distance by your vehicle's MPG to get the gallons, then multiply by the price per gallon. A 400-mile trip at 18 MPG burns 400 ÷ 18 = 22.22 gallons, which costs $139.56 at $6.28 a gallon. Add a fuel surcharge percentage on top of that base cost if your contract has one. That is exactly what the calculator above does.
How much should I charge for diesel per mile?+
Work it out as fuel first, then mark it up. Divide the total fuel cost by the trip distance — for example, $531.38 over 500 miles is about $1.06 per mile fuel-only. That $1.06 is only fuel: a charge-per-mile rate needs your driver, maintenance, insurance, permits, and tolls on top of it. The fuel-only number is the floor, not the quote.
How many gallons of diesel will a 500-mile trip take?+
Divide 500 by your MPG. At 6.5 MPG that is 76.9 gallons; at 8 MPG it is 62.5; at 18 MPG it is 27.8. Gallons = distance ÷ MPG, so every 0.5 MPG matters more the lower your economy is.
What is the current average diesel price?+
The EIA's weekly on-highway survey put the U.S. average at $6.276 per gallon for the week of October 19, 2026 (released October 20), including all taxes. Regional averages that week ran from $5.740 in the Lower Atlantic to $8.242 in California — see the regional table above. The calculator prefills the national average; swap in your region or your actual pump price for a closer estimate.
How does a fuel surcharge work?+
A fuel surcharge is a percentage applied to the base fuel cost — most often in freight, delivery, and service contracts — so that rising diesel prices do not eat the provider's margin. On a $483.08 base, a 10% surcharge adds $48.31 for a $531.38 total. Surcharge formulas vary by contract (some work from a baseline price or an index); the calculator applies a straight percentage of the base fuel cost.
What MPG should I enter for my truck?+
Your own measured number: track miles driven between fills and divide by the gallons it took to refill. Real economy shifts with load, terrain, speed, and headwind, and window-sticker or catalog figures are usually optimistic. This page deliberately does not publish MPG-by-vehicle-class tables because the ranges vary and we could not verify them against a primary source — your fill-up log is better data than any class average.
Does the calculator handle round trips?+
Enter the round trip as a doubled distance — 500 miles out and back is 1,000 miles in the distance field. The calculator prices one continuous distance and does not add a return leg automatically, so doubling it yourself is the accurate way to price both directions.
Can I price multiple legs or fill-ups?+
Not in one run: the calculator assumes one constant distance, MPG, and price. Price each leg as its own run and add the totals, or sum the leg distances first if the MPG and price are the same across legs. For fill-up planning, divide your tank size by the gallons needed to see how many stops the trip requires.
Why is diesel so much more expensive in California?+
In the EIA's weekly survey, California runs well above every other region — $8.242 versus the $6.276 national average in the week of October 19, 2026. State taxes, fuel rules, and supply factors all contribute. If your trip stays inside one region, use that region's figure instead of the national default.
Is the price per gallon pre-filled here the price I'll pay?+
Probably not exactly. The default is the EIA national weekly average (including taxes) for the week of October 19, 2026 — a starting point, not a live feed, and pump prices vary by state, station, and day. The estimate is only as good as the price you enter, so put in the price on the sign at your station.
This diesel fuel cost calculator provides estimates from the distance, fuel economy, price, and surcharge you enter. The default price is a dated weekly government survey average, not a live or local pump price, and real fuel economy varies with load, terrain, speed, and weather. Results are for planning and quoting assistance only and are not a freight rate, contract terms, or financial advice.