Calculate quarterly IFTA fuel tax by jurisdiction: fleet MPG from your distance and fuel, then net taxable gallons and tax due or credit per state.
Independently built and reviewed by the FleetOpsClub research team. Published October 8, 2026. Last verified October 8, 2026.
Work out this quarter’s IFTA position
Start with the quarter’s totals. Total distance and total fuel cover everything the qualified vehicles did, trip-permit running included, because that is what fleet MPG is derived from. The jurisdiction rows below cover only the member jurisdictions you are reporting.
Distance and fuel by jurisdiction
Leave a row blank if you did not run there. Rates are yours to enter — this page publishes none, because every one of them changes quarterly.
Your quarterly position
How the return is actually computed
IFTA does not tax the fuel you bought where you bought it. It taxes the fuel you burned in each jurisdiction, then credits you for the tax you already paid at the pump. The gap between those two numbers is your bill or your refund, and the whole return turns on one figure: your fleet’s miles per gallon for the quarter.
net taxable gallons = taxable gallons − tax-paid gallons
tax due / (credit) = net taxable gallons × jurisdiction tax rate
The order matters. Fleet MPG is a single number for the whole fleet across the whole quarter, not a per-truck or per-state figure, and it is what converts distance into gallons in every jurisdiction. Get it wrong and every line on the return is wrong by the same proportion.
Why total distance is a separate field from the rows beneath it
This is the field most IFTA calculators collapse, and collapsing it produces a wrong MPG. Total distance and total fuel are measured over all the activity of your qualified vehicles — including distance run under a temporary trip permit, and including non-member jurisdictions. That activity belongs in the MPG calculation because the fuel was genuinely burned.
It does not belong on the return. Trip-permit distance is reported to whoever issued the permit, not through IFTA, and a non-member jurisdiction has no line on the form. So the sum of the jurisdiction rows is normally smaller than your total distance, and the calculator above reports the difference back to you rather than quietly reconciling it. If the two figures match exactly, you have claimed you ran no trip permits all quarter — which is fine, as long as it is true.
If the rows add up to more than the total, the calculator says so. That mismatch is one of the first things an audit looks for, and finding it yourself costs nothing.
What tax-paid credit actually covers
A fuel receipt is not automatically a credit. Tax-paid gallons earn credit only where the fuel was taxed by a member jurisdiction and put into a qualified motor vehicle. Both conditions, every time.
Fuel bought tax-exempt or ex-tax earns no credit — there was no tax paid to credit.
Fuel bought outside the member jurisdictions earns no credit, however good the receipt.
Fuel burned in a vehicle that does not meet the qualified-vehicle definition is outside the agreement entirely, so neither its distance nor its gallons belong on the return.
Bulk fuel is credited when it is withdrawn into a qualified vehicle, not when the tank was filled, and it needs withdrawal records to support that.
The practical failure is mixing fleets. If the same fuel card buys for qualified trucks and for pickups that are not qualified, the gallons on the card are not the gallons on the return, and nothing on the card tells you which were which. That split has to come from your own records.
The penalty MPG of 4.00, and what it costs
Here is the part almost nothing else on this topic mentions. Your reported MPG is only as good as the distance and fuel records behind it. When those records are inadequate — missing trip reports, distance that cannot be traced to a source document, fuel receipts that do not reconcile — an auditor does not simply ask you to fix them. They may assess the return at a standard MPG of 4.00, or alternatively reduce your reported MPG by 20%.
Both moves work in the same direction, and it is worth understanding why. Taxable gallons are distance divided by MPG, so a lower MPG means more gallons attributed to every jurisdiction. Your tax-paid gallons do not change, because those come from receipts. So net taxable gallons rise in every jurisdiction at once and the bill rises with them.
Run it yourself: enter your real quarter, then switch the MPG dropdown to 4.00 and recalculate. For a fleet genuinely averaging 6.5 MPG, the penalty basis attributes roughly 60% more gallons to every jurisdiction. That is the real exposure in an IFTA audit, and it is a recordkeeping problem rather than a tax one. The fix is upstream: distance captured per jurisdiction per trip, fuel receipts that tie to a vehicle, and both retained for the required period.
Where the tax rates come from — and why they are not on this page
Every member jurisdiction sets its own rate, and the rates change every quarter. A rate table published on a page like this one is wrong within 90 days and stays wrong, quietly, while people file from it. So this calculator takes rates as an input and publishes none.
Pull the current quarter’s figures from the IFTA tax rate matrix published by IFTA, Inc. and enter them in the rows above. A few jurisdictions also apply surcharges that are reported on a separate line from the base rate, so check the matrix footnotes for the jurisdictions you ran in. Where the matrix and your base jurisdiction disagree, your base jurisdiction governs — they are who you file with.
A worked quarter
Totals: 13,000 miles and 2,000 gallons across all activity → fleet MPG of 6.50.
Illinois: 4,400 miles ÷ 6.50 = 676.9 taxable gallons. Bought 700 tax-paid gallons there, so net taxable gallons are −23.1 — a credit position in Illinois, because the trucks fuelled there and burned the fuel elsewhere.
Indiana: 2,800 miles ÷ 6.50 = 430.8 taxable gallons against 300 bought, so 130.8 net taxable gallons are owed. Ohio: 3,900 ÷ 6.50 = 600.0 against 500 bought, so 100.0 owed. Kentucky: 1,900 ÷ 6.50 = 292.3 against 350 bought, so 57.7 in credit.
Multiply each jurisdiction’s net taxable gallons by that jurisdiction’s current rate and add them up. The credits and the debits net against each other, which is the point of filing one return instead of four. Note the reconciliation: 4,400 + 2,800 + 3,900 + 1,900 = 13,000, so in this quarter there was no trip-permit distance and the rows account for all of it. Switch the dropdown to the 4.00 penalty MPG and every one of those gallon figures rises by 62%, while the tax-paid gallons do not move.
Getting the inputs together
The calculator is the easy part. Assembling four clean numbers per jurisdiction out of a quarter of trip sheets and fuel receipts is the work, and it is where most of the errors live. Two worksheets on this site are built for exactly that handoff:
IFTA Mileage & Fuel Tax Worksheet — per-jurisdiction rows for distance and gallons, with the fleet MPG calculation driving the gallons attribution. Fill this in first; its columns are the inputs above.
IFTA Quarterly Filing Worksheet — laid out in the order an IFTA return is filed, so you can transfer the figures straight across.
For the regulation behind all of it, see the IFTA guide and the IFTA glossary entry. If your distance records come off an ELD or GPS rather than paper, most GPS fleet tracking platforms export per-jurisdiction distance directly, which removes the largest single source of IFTA error.
This page is a calculation aid, not tax advice. Your base jurisdiction’s rules govern your return.
Quick answers to the questions buyers usually ask once the category, software, or rollout details start getting more specific.
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Divide total distance by total fuel to get your fleet's MPG for the quarter. Divide each jurisdiction's distance by that MPG to get the gallons you burned there. Subtract the tax-paid gallons you bought in that jurisdiction to get net taxable gallons, then multiply by that jurisdiction's current tax rate. Jurisdictions where you bought more than you burned produce a credit, which nets against the ones where you owe.
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It goes into the fleet MPG calculation but not onto the return. Total distance and total fuel cover all of a qualified vehicle's activity, trip-permit running included, because that fuel was genuinely burned and MPG has to reflect it. The distance itself is reported to whoever issued the permit, so it does not appear as a jurisdiction line on the IFTA return. That is why total distance is normally larger than the sum of the jurisdiction rows.
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When distance or fuel records are inadequate, an auditor may recompute the return at a standard 4.00 MPG instead of your reported figure, or alternatively reduce your reported MPG by 20 percent. Because taxable gallons are distance divided by MPG, a lower MPG attributes more gallons to every jurisdiction while your tax-paid gallons stay fixed, so the assessment rises across the whole return at once. For a fleet averaging 6.5 MPG, the 4.00 basis attributes roughly 60 percent more gallons. It is a recordkeeping exposure rather than a tax one.
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Only fuel that was taxed by a member jurisdiction and put into a qualified motor vehicle. Fuel bought tax-exempt earns no credit because no tax was paid, fuel bought outside the member jurisdictions earns no credit regardless of the receipt, and fuel burned in a vehicle that is not qualified falls outside the agreement entirely. Bulk fuel is credited on withdrawal into a qualified vehicle and needs withdrawal records to support it.
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Because they change every quarter in every jurisdiction. A rate table published on a page stays wrong between updates while people file from it, so this calculator takes rates as an input instead. Pull the current quarter's figures from the IFTA tax rate matrix published by IFTA, Inc., and check the footnotes for jurisdictions that add a surcharge reported on its own line.
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Across the whole fleet for the whole quarter. It is one number: total distance divided by total fuel for all qualified vehicles. Per-truck figures are useful for operations, but the return uses the fleet average to convert distance into gallons in every jurisdiction, which is why an error in that single figure moves every line on the return by the same proportion.
