What per diem is, in plain English
Per diem is a flat daily amount the IRS lets you deduct for meals and incidental expenses while you're away from home overnight for work — instead of saving every gas-station receipt for a year. For truckers who fall under DOT hours-of-service rules, it's one of the biggest, cleanest deductions on the return, and it costs nothing but a little bookkeeping.
Full days vs partial days
The rule is simple once you see it:
- Full day — any day you're away from your tax home and need rest, from midnight to midnight. You claim the full daily rate.
- Partial day — the day you leave and the day you get home. Each is claimed at 75% of the daily rate. A typical week-long trip has 5 full days and 2 partial days.
That's the whole method. Count the nights, split out the two travel days on each trip, apply the rate, then take 80% of the total as your deduction. The calculator does the arithmetic; you just need an honest day count from your logs.
Keep it clean for the IRS
You don't need meal receipts to use the per diem method, but you do need to prove you were on the road. Your ELD records, trip logs, and settlement statements do that. Keep them at least three years. The number this calculator gives you is an estimate to plan around — your tax preparer will put the final figure on the return.
Per diem sits right next to your take-home pay and cost per mile as one of the levers that decides what you actually keep. Big deduction, small effort.