Fuel taxes are owed to the state where the fuel is burned, not where it's bought. Before IFTA, that meant stopping at every border for permits and filing with every state. The International Fuel Tax Agreement replaced that with one quarterly return, filed with your home state, that settles up across all member jurisdictions — the 48 contiguous US states and 10 Canadian provinces.
What IFTA is
You file a single consolidated quarterly return with your base jurisdiction (the state that issues your IFTA license and decals). It reports miles traveled and fuel purchased in each jurisdiction. The system then reconciles them: states where you burned more fuel than you bought get paid; states where you over-purchased issue you a credit. Note that IFTA, Inc. does not issue licenses or decals — your base jurisdiction does.
Who has to file
You need an IFTA license and must file quarterly if you operate a qualified motor vehicle across state lines. A qualified vehicle is one that:
- has two axles and a gross (or registered gross) weight over 26,000 lbs; or
- has three or more axles on the power unit, regardless of weight; or
- is used in a combination exceeding 26,000 lbs gross weight.
Intrastate-only carriers who never cross state lines aren't subject to IFTA. Recreational vehicles used purely for personal travel are exempt. Confirm with your base jurisdiction before assuming an exemption applies.
How the math works
It's four steps, and every one depends on clean data:
- Fleet MPG for the quarter = total miles (all jurisdictions) ÷ total gallons purchased. Use the full quarter's actual totals — not last quarter's figure, not your best tank.
- Gallons consumed per state = miles in that state ÷ fleet MPG. This is what you burned there, regardless of where you bought it.
- Compare to gallons purchased in that state. Burned more than you bought → you owe tax. Bought more than you burned → you get a credit.
- Net it all across jurisdictions, at each state's current rate, and file with your base jurisdiction.
Deadlines & penalties
Four returns a year, each due the last day of the month following the quarter (shifting to the next business day if it falls on a weekend or holiday):
- Q1 (Jan–Mar) — due April 30 · Q2 (Apr–Jun) — due July 31
- Q3 (Jul–Sep) — due October 31 · Q4 (Oct–Dec) — due January 31
You must file even if you owe nothing — a zero return is still a return. Filing late generally triggers a penalty of $50 or 10% of the net tax due, whichever is greater, plus interest accruing monthly from the due date. Continued non-filing can get your IFTA license suspended or revoked, and without a valid IFTA decal you can't legally run interstate — exposing you to roadside fines and potential out-of-service orders. Reinstatement means filing every missing return and paying all penalties and interest.
If you miss a deadline, file immediately anyway. You'll still owe the penalty, but you stop the revocation clock and prevent the state from estimating your liability for you — which it will do in its own favor.
Records that survive an audit
Keep everything for four years from the filing date:
- Miles by jurisdiction — from ELD/GPS logs, trip sheets with state-line odometer readings, or routing software. Don't estimate; auditors cross-reference against fuel consumption and toll records.
- Fuel receipts showing date, location/seller, gallons, price, and vehicle. A credit-card statement is not a valid receipt — without a proper one you lose the tax-paid credit and effectively pay fuel tax twice.
- The filed return plus submission confirmation and payment proof.
Common mistakes
- Estimating or rounding state-by-state mileage — the single most common audit trigger.
- Carrying forward last quarter's MPG instead of recalculating.
- Missing or invalid receipts (cash purchases with no photo).
- Skipping a zero-activity quarter.
- Using stale tax rates instead of the current quarter's matrix.
How Ashton helps
IFTA is a quarterly financial close disguised as paperwork — and it's exactly what slips when you're driving. Ashton's compliance and back-office team keeps mileage and fuel records reconciled continuously (from your ELD and fuel-card data), so the return is 90% done before the quarter ends and filing is a review, not a rebuild. We also track your credential calendar — IFTA, UCR, MCS-150 — so renewals don't sneak up. You keep your authority; we keep the deadlines. Nothing here is tax advice — verify current rates and requirements with your base jurisdiction.
Sources & further reading
- IFTA quarterly filing requirements and qualified-vehicle definitions — e.g. California CDTFA IFTA return instructions (weight/axle thresholds, zero returns, base jurisdiction).
- IFTA, Inc. official tax rate matrix — rates change quarterly; licenses and decals are issued by your base jurisdiction, not IFTA, Inc.
- Industry compliance guidance on IFTA penalties ($50 or 10% of net tax due, whichever is greater, plus interest), four-year record retention, and audit triggers.
This article is general information for trucking and logistics businesses, current as of July 2026. It is not legal, tax, insurance, or financial advice. Rules, rates, and fees change — confirm current requirements directly with the FMCSA and your own licensed advisors before acting.