Semi truck fill-up cost calculator: what the next fill costs
Enter your tanks, the gauge reading and the diesel price. The semi truck fill-up cost calculator shows the gallons you need, what the fill costs and the miles it adds.
Defaults are an example truck with two 150-gallon tanks. The diesel default is the EIA U.S. average for the week of Oct 5, 2026.
COST TO FILL
$1,394.77
225 gallons
FULL TANKS ARE WORTH
$1,860
300 gallons at this price
- On board now
- 75 gal
- Miles this fill adds
- 1,463
- Range on full tanks
- 1,950 mi
- Each 10 cents a gallon
- $22.50
Gauges are rough, especially near empty, and the pump may stop short of the brim. Plan a reserve and do not run tanks dry.
POSTED: EIA, Gasoline and Diesel Fuel Update, on-highway diesel, week of Oct 5, 2026 · checked Oct 2026
A $1,395 fill-up needs loads that pay for it. Our dispatchers plan loads around your hours and home time, and count fuel when they price a load. Dispatch runs 5% of gross for one truck, and you confirm every load.
By Nathan Beck · Updated October 2026
Fuel is the biggest bill most trucks run, and a single fill-up can cost more than a car payment. Knowing the number before you pull up to the pump helps you decide where to fill, how much to buy and whether a load still pays. This semi truck fill-up cost calculator works it out from your tanks, your gauge and the price on the sign.
Semi truck fuel tanks
Most semis carry one or two saddle tanks, one on each side, and sizes vary with the truck and how it was specced. The capacity is usually on a tag on the tank or in the truck's paperwork. Two practical points:
- Usable fuel is less than the stamped size. Tanks are rarely filled to the brim, and the bottom of the tank is reserve you should not plan to use.
- The gauge is approximate. It reads in rough steps, and it can be least accurate near empty.
Tank caps, straps, steps and fuel gauges wear out like any other part. Our guide to semi truck driver accessories covers the small kit that makes fueling easier, from gloves to a spare locking cap.
How it is calculated
- Capacity: the number of tanks times the size of each.
- On board: capacity times the gauge reading.
- Gallons to fill: capacity minus what is on board.
- Cost: gallons to fill times the diesel price, plus any DEF you add.
- Range: gallons added times your MPG, and full tanks times MPG.
The default price is the EIA U.S. average of $6.199 a gallon for the week of October 5, 2026. Pick any EIA region, from the Lower Atlantic at $5.699 to California at $8.082, or type the price on the sign.
POSTED: EIA, Gasoline and Diesel Fuel Update (week of Oct 5, 2026) · checked Oct 2026
What a good result and a bad result look like
A good result is a fill you planned: at a stop on your route, at a price you checked, with enough fuel to reach the next cheaper state. A bad result is a forced fill at the most expensive station on the road because the gauge got too low, or a full load of fuel that pushes you over gross weight.
One thing to know when chasing cheap states: if you run under IFTA, fuel tax is settled each quarter by the miles you drove in each state, not where you bought the fuel. Filling in a low-tax state lowers your pump price, but the tax you owe follows your miles.
Fueling stops and parking go together. Many drivers fuel where they will park for the night, and some truck stops tie parking to a fuel purchase; truck parking prices explains how that works, and the truck parking cost calculator adds up a month of it. To price fuel for a whole trip, use the trip fuel cost calculator.
Fuel is part of every load
The fill-up is only worth it if the loads cover it. Our dispatchers count fuel when they price a load, plan loads around your hours and home time, and aim each day to end near a legal place to stop. You confirm every load and the rate con comes to you. See how it works for owner operators, or apply in about two minutes.
Questions about this calculator
How much does it cost to fill up a semi truck?
It depends on your tank size, how empty you are and the price at the pump. As an example, filling two 150-gallon tanks from a quarter full takes 225 gallons; at the EIA U.S. average diesel price for the week of October 5, 2026 that is about $1,395. Prices differ by more than two dollars a gallon between regions, so use your own.
What is a semi truck's fuel tank capacity?
There is no single size. Most semis carry one or two saddle tanks, and the size depends on the make, model and how the truck was ordered. The capacity is usually on a tag on the tank or on the truck's spec sheet. Remember that the usable amount is a little less than the stamped size, and the gauge is only approximate.
Should I fill both tanks every time?
Not always. Full tanks add weight, which matters when you are close to legal gross, and fuel prices change a lot from state to state. Many drivers fill where diesel is cheaper and buy just enough elsewhere to get there. The trip fuel cost calculator helps you see how far a fill will take you.
Does the calculator include DEF?
It can. Diesel exhaust fluid goes in its own tank, so add the gallons of DEF you plan to buy and the price per gallon, and the tool adds it to the total. DEF use is a small share of fuel use, so most drivers top it off every few fill-ups rather than at every stop.
PARK BY: PLANNED WITH YOU
Loads priced with your fuel in mind
We count fuel when we price a load. You approve every one.