About Per Mile Math
A small set of calculators for owner-operators, built around one rule: every number has to be traceable to a source and dated, or it does not go on the page.
What this site is
Per Mile Math is an independent reference and calculation tool for owner-operators and small fleets. It exists because the arithmetic behind a quarterly IFTA return is simple but easy to get wrong, and because most of what is published about it online does not say which quarter its rates belong to.
Where the IFTA rates come from
The rate table is read from the official IFTA, Inc. tax rate matrix for the quarter, which aggregates every member jurisdiction's published rate. We parse the matrix into structured data and display it without adjustment; where a jurisdiction has not yet reported, the cell says so.
Two things are deliberately preserved rather than tidied up:
- Jurisdictions that report no rate stay blank. Where a jurisdiction publishes no rate for a fuel type, this site shows unavailable. It does not estimate, interpolate, or substitute a neighbouring state's figure.
- Every table carries its quarter. A rate without a quarter label is not usable, so the quarter is shown wherever the rates appear.
The authoritative matrix is published at iftach.org/taxmatrix4. If this site and the official matrix ever disagree, the official matrix is correct and this site is wrong. Please check it before you file.
How often data is updated
IFTA rates are set quarterly, so the table is refreshed at each quarter boundary rather than continuously. The retrieval date shown on the rate table is the date the data was pulled, not the date the jurisdiction changed it.
Jurisdictions can also issue mid-quarter notices — fuel tax holidays, split-quarter rates that apply to one fuel but not another, and temporary relief programmes. Those are announced separately from the matrix and are not automatically reflected in a quarterly table. If you are filing for a quarter in which your jurisdiction announced something unusual, confirm it against the jurisdiction's own notice.
What the calculators do
The IFTA calculator applies the standard IFTA settlement method: fleet average mpg from total miles and total gallons, gallons taxed per jurisdiction from that jurisdiction's miles, net gallons as gallons taxed minus gallons purchased there, and tax as net gallons times that jurisdiction's rate. It sums the result across jurisdictions.
The cost per mile calculator does arithmetic on the numbers you enter. It has no market data and makes no assumptions about your operation.
All calculation happens in your browser. Nothing you type is transmitted, stored, or logged.
What the calculators do not do
- They do not file anything, and they are not connected to any filing system.
- They do not know about split-quarter rates, tax holidays, or jurisdiction-specific exceptions unless those are reflected in the published rate.
- They do not verify that your miles and gallons are correct. That is your records' job.
- They do not give tax or legal advice.
Treat every output as a cross-check against your own records and against the official matrix — not as the return itself.
Independence and funding
Per Mile Math is not affiliated with IFTA, Inc., any state department of revenue, any motor carrier, or any fuel card or factoring company. The site may earn commission from services linked on some pages; where that is the case it is disclosed on the page and in the affiliate disclosure. Commercial relationships do not influence rates, calculations, or the content of the reference pages.
Corrections
If a rate, a formula, or an explanation on this site is wrong, it should be fixed rather than defended. Corrections are welcome and are the fastest way to make the site better — particularly from people who file these returns for a living.
Primary data source: official IFTA, Inc. tax rate matrix (4Q2026), published at iftach.org/taxmatrix4. Last content review: 14 November 2026.