How to File IFTA for Q2 2026: A Step-by-Step Walkthrough (Due July 31)
Second-quarter IFTA is due. The Q2 2026 reporting period closed June 30, and your return has to be filed and paid by July 31, 2026. Miss it and you're looking at a $50 minimum penalty (or 10% of the net tax owed, whichever is greater) plus monthly interest — every quarter you're late.
If you've been putting it off because the per-state mileage breakdown is a headache, this is the walkthrough that gets it done. We'll go step by step: figure out your miles in each state, compute the tax, and file — and you can do the whole calculation for free with our IFTA Mileage & Tax Calculator, no signup and no spreadsheet.
First: is Q2 2026 actually due for you?
You file a quarterly IFTA return if you run a qualified motor vehicle (two axles over 26,000 lbs GVW, three or more axles regardless of weight, or a combination over 26,000 lbs) in two or more IFTA jurisdictions. You file even if you owe nothing, even if the truck sat for part of the quarter, even if you only crossed one state line.
Here's the full-year deadline calendar so you know what's next:
| Quarter | Period | Due date |
|---|---|---|
| Q1 | Jan 1 – Mar 31 | April 30 |
| Q2 | Apr 1 – Jun 30 | July 31 |
| Q3 | Jul 1 – Sep 30 | October 31 |
| Q4 | Oct 1 – Dec 31 | January 31 |
So the return covering April, May, and June is the one on the clock right now.
What you need before you start
For each truck, for the Apr–Jun quarter, you need three things:
- Miles driven in each state/province — broken out per jurisdiction.
- Gallons of fuel purchased in each state/province — from receipts or fleet-card statements.
- Your totals — total miles and total gallons across everything.
Fuel gallons you already have — they're on your receipts and card statements. The part that eats everyone's afternoon is the per-state miles. That's Step 1, and it's the step the calculator does for you.
Step 1 — Get your per-state miles
Open the IFTA calculator and start on the Miles Calculator tab.
Instead of reading odometers at state lines or reconstructing routes from memory, you just enter the trip:
- Pickup — city, or paste a full address
- Any intermediate stops — add as many as the trip had
- Delivery
The calculator routes the full trip the way the truck actually drove it and returns miles per IFTA state automatically. Run each trip from the quarter, and it accumulates your state-by-state mileage for you — no highway-atlas math, no guessing at where you crossed from Oklahoma into Arkansas.
Already have an ELD mileage report? If your ELD or fleet software exports a state-mileage PDF, a free MyCarrierVault account lets you upload it and have every state's miles read off the document automatically — no manual entry at all. That's the fastest path if you're running more than a truck or two. Create a free account (30 days, no card) to use the PDF auto-fill.
Why the mileage step matters at audit time: "Exactly 10,000 miles" in a state is a red flag — real records have odd decimals. Routing-based miles give you defensible, non-round numbers backed by an actual trip, which is exactly what an auditor wants to see.
Step 2 — Compute the tax
Switch to the Tax Calculator tab. Enter the per-state miles you just calculated (or your ELD/trip totals) and the gallons of fuel you bought in each state. The calculator runs the standard IFTA chain for you:
- Fleet MPG = total miles ÷ total gallons
- Gallons burned in each state = that state's miles ÷ fleet MPG
- Net taxable gallons = gallons burned − gallons purchased in that state
- Tax owed (or credit) = net taxable gallons × that state's tax rate
Buy more fuel in a state than you burned there and you get a credit; burn more than you bought and you owe. Your quarter's bottom line is the net across every jurisdiction.
The rates matter here, and they're the other thing people get wrong. New-quarter diesel rates often aren't published until several weeks into the quarter, so filing early with last quarter's numbers can put you off by 5–10% in any state that adjusted. Our calculator pulls the current per-state rates straight from iftach.org and falls back to the prior quarter only when the new ones aren't posted yet — and there's a Refresh rates button if you want to force the latest pull before you file.
(Want the full breakdown of the math, surcharges, and worked examples? See our IFTA Quarterly Filing Guide.)
Step 3 — File with your base state
The calculator gives you every number that goes on the return. To actually file, log into your base state's IFTA portal (the state that issued your IFTA license and decals) and enter the per-state miles, gallons, and tax figures. Most states require electronic filing now. Pay any balance due by July 31 to avoid the penalty.
You can print or save the calculator's output as a PDF to keep alongside the filing — handy for your records and for whoever actually submits it.
Don't forget these three things
- Oregon is special. Oregon doesn't tax diesel at the pump — it uses a weight-mile tax instead. On your IFTA return, Oregon's rate is $0.00 (the calculator locks it there automatically), but you still report Oregon miles and gallons, and you file a separate Oregon weight-mile return through ODOT.
- Surcharge states. Indiana, Kentucky, and Virginia carry a surcharge on top of the base rate — make sure those are accounted for.
- Keep your records for four years. Trip documentation and fuel receipts have to be retained for four years from the return's due date. Store this quarter's supporting docs somewhere you'll find them if an audit notice arrives.
Missed a past quarter?
If a previous quarter slipped, file it anyway — the penalty for a filed-late return is far smaller than the trouble that comes from a missing return. Repeated non-filing can get your IFTA license suspended, which legally grounds you at the state line. Catch it up, then set a reminder so Q3 (due October 31) doesn't sneak up the same way.
Get Q2 done today
The whole point of the deadline is that it doesn't wait. You can have your Q2 2026 numbers calculated in the next few minutes:
- Open the free IFTA Mileage & Tax Calculator — no signup required.
- Use the Miles Calculator tab to get per-state miles from your trips.
- Use the Tax Calculator tab to compute what you owe.
- File with your base state and pay by July 31, 2026.
If you run more than a couple of trucks and you're tired of rebuilding this from a shoebox every 90 days, MyCarrierVault stores your trip miles, fuel data, and rate lookups quarter over quarter — and reminds you before each deadline — so next quarter is a five-minute job instead of a lost afternoon. Free for 30 days, no credit card.