Work out what a trip burns in fuel before you commit to the rate.
Fuel is the largest variable cost on most runs and the one that moves most between quarters, so knowing the bill before accepting a rate turns a lane from a guess into a decision. Use your real MPG rather than the manufacturer figure, and enter idle hours separately — a loaded truck running climate control burns roughly 0.8 gallons an hour, which never shows in a miles-per-gallon figure but very much shows on the fuel card. The line worth studying is what half a mile per gallon is worth on the same trip: across a year it usually dwarfs anything you win negotiating rates, and unlike rates it is entirely in your control.
The things carriers ask most about this calculation.
Divide trip miles by your truck's MPG to get gallons, then multiply by the price per gallon. A 1,200-mile run at 6.5 MPG is about 185 gallons, or roughly $1,007 at $5.45 diesel.
Roughly 0.8 gallons an hour for a loaded truck running climate control. Eight hours of idling is about six gallons, so a week of overnight idling can quietly cost more than $100.
On 120,000 miles a year at $5.45 diesel, going from 6.5 to 7.5 MPG saves roughly $13,400. That is why speed discipline and tire pressure matter more to margin than most rate negotiations.
Yes, as a variable cost. It is usually the largest single line after driver pay, and it moves enough quarter to quarter that a stale figure will make lanes look profitable when they are not.

