FOR SMALL CARRIERS AND OWNER-OPERATORS FILING THEIR OWN IFTA

The surcharge is not another tax rate.

Indiana, Kentucky and Virginia collect part of their diesel tax on the return instead of at the pump, and that part is charged on every taxable gallon you burned there — with no credit for fuel you bought there. On the quarter loaded below, the tax line across five jurisdictions nets to a credit of $91.53. The return owes $479.37. Model the surcharge as one more rate to be netted and you file $328.42 short, on a quarter you thought was a refund.

Put your own quarter in. Everything runs in this browser; nothing is uploaded and nothing is filed.

How is IFTA quarterly tax actually calculated? — the worked example, line by line

This calculator vs. a spreadsheet — the two rules a hand-built worksheet almost always gets wrong. Already using a paid prep service? See how this compares to ExpressIFTA.

Your quarter, jurisdiction by jurisdiction

One row per jurisdiction you ran in. Rates come from the official IFTA rate table for the quarter you are filing — this tool ships none, because they change quarterly in 58 jurisdictions and a stale rate in a filed return is the worst place to be wrong. Leave taxable miles blank unless the jurisdiction exempts some of them; blank means all miles are taxable. Leave surcharge blank unless the jurisdiction levies one.

Jurisdiction Total miles Taxable miles Tax-paid gallons Tax rate $/gal Surcharge $/gal

This quarter is saved automatically to this browser, so it is still here on your next visit — “Clear the example” erases both the fields and the saved copy. “Copy a link” puts every row and both late-filing fields into the URL after the #, which is never sent to a server or logged anywhere, so sending it to a bookkeeper or co-owner uploads nothing.

If the return is late

Leave both at zero for an on-time return. Interest accrues to each jurisdiction you owe, at one twelfth of the annual rate per month or part month — a credit somewhere else does not offset it, which is why a return that nets to a refund can still carry interest. The annual rate is set for the calendar year by the International Fuel Tax Association; take it from there rather than from here.

The return, line by line

This is the shape of the jurisdiction schedule on an IFTA return. Taxable gallons come from your fleet MPG, not from what you bought in the state; the surcharge column is charged on taxable gallons with nothing credited against it.

Jurisdiction Taxable gallons Tax-paid Net taxable Tax Surcharge Interest Row total

Press “Work the return” and the schedule fills in.

Net due to your base jurisdiction

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Press “Work the return” to see the quarter.

Common questions

How do you calculate IFTA taxable gallons?

Taxable gallons in a jurisdiction are that jurisdiction’s taxable miles divided by the average MPG of your whole fleet across the whole quarter — not the gallons you bought there. On the worked example this page opens with, the fleet ran 29,320 miles on 3,890 gallons, so its average is 7.54 MPG, and Indiana’s 6,150 miles become 815.65 taxable gallons whether the truck fuelled there or not. Computing a separate MPG per jurisdiction is the most common way a hand-built worksheet produces figures that look reasonable and reconcile to nothing.

Why does my IFTA return say I owe money when I have a fuel credit?

Almost always the surcharge. Indiana, Kentucky and Virginia collect part of their diesel tax as a surcharge on the return rather than at the pump, and it is charged on all your taxable gallons in that state with no credit for fuel you bought there. On the worked example the tax line across five jurisdictions nets to a credit of $91.53 — and the return still owes $479.37, because the surcharge adds $570.90 that no amount of fuel buying reduces. A worksheet that treats the surcharge as another tax rate, netted against the credit, reports $242.48 instead: a $328.42 understatement in a single quarter.

Does buying more fuel in Kentucky reduce my surcharge?

No, and this is the part that costs carriers money in both directions. Buying fuel in a surcharge state reduces the tax line, because tax-paid gallons are credited against taxable gallons. It does nothing whatever to the surcharge line, which is charged on taxable gallons — the fuel you burned there — regardless of where you bought it. So fuel-buying strategy moves one of the two lines and not the other, and any plan built on the assumption that it moves both will be wrong by the whole surcharge.

What tax rates should I use?

The ones on the official IFTA rate table for the specific quarter you are filing, which is published by the International Fuel Tax Association and republished by every base jurisdiction. This calculator deliberately ships no rate table. Rates change every quarter across 58 jurisdictions and some change mid-quarter, so a table baked into a tool would be stale within weeks and stale in the worst possible place — a filed tax return. Enter the rate and, where one applies, the surcharge rate for your fuel type, and the arithmetic is yours to check.

What counts as taxable miles versus total miles?

Total miles is every mile the qualified vehicle ran in that jurisdiction. Taxable miles is that figure less any miles the jurisdiction exempts — the exemptions vary by jurisdiction and typically cover things like some toll miles, fuel-trip-permit miles, and certain off-highway use. Most carriers have no exempt miles at all, so leaving the taxable column blank here means all the miles are taxable. Exempt miles come off the taxable line but stay in the fleet MPG, because the fleet really did drive them on the fuel it really did burn. What each jurisdiction exempts is its determination, not this tool’s.

Do I still owe interest if my return nets to a refund?

Yes, if you filed late. IFTA interest accrues to each jurisdiction you owe tax to, at one twelfth of the annual rate for each month or part of a month, and a credit due back from another jurisdiction does not offset it. That is why this calculator computes interest on the jurisdictions in debit alone rather than on the netted total, and flags the case where a return in overall credit still carries interest. The annual rate is set for the calendar year and published by the International Fuel Tax Association — enter it rather than reading one from this page, for the same reason the tax rates are inputs.

Do I need to file IFTA if I only ran in one state?

IFTA covers qualified vehicles operating in two or more member jurisdictions, so a quarter run entirely inside your base jurisdiction may not need a return — but most base jurisdictions require licensees to file every quarter regardless, including a zero return. This calculator flags a return with a single jurisdiction rather than assuming either way, because what your licence obliges you to file is a question for your base jurisdiction and not one arithmetic can answer.

Is any of this uploaded?

No. There is no account and the page makes no network requests — it runs entirely in your browser. Your mileage, your fuel purchases, the jurisdictions you run and the figures worked out from them are never sent anywhere and never appear in a usage count. The optional counter records only which features were used and the day, stored on your own device, and it switches itself off for browsers sending Do Not Track or Global Privacy Control.

Can I save this quarter or send it to someone else?

Yes. Your rows and both late-filing fields are saved to this browser automatically, so they are still here on your next visit. The copy-link button puts the same figures into the page’s own address after the #, which is never sent to a server or logged anywhere, so opening that link reopens the exact return and sending it uploads nothing.

Is this tax advice, and can I file from it?

No to both. It is a worksheet: arithmetic on figures you type, using rates you supply. It is not tax advice and it is not a filing — it files nothing, transmits nothing, and makes no determination about what your base jurisdiction requires, which miles a jurisdiction exempts, whether your vehicle is qualified, or what you owe. Your base jurisdiction assesses the return. Check every figure against your own trip and fuel records and the official rate table, and ask a qualified tax professional before you file from it.