A truck depreciation calculator estimates how much value your truck loses each year, using purchase price, salvage value, and useful life as inputs. Enter $180,000 for a new Class 8 tractor, $30,000 for salvage, and 5 years of service, and the straight-line result is $30,000 per year. Owner-operators need that figure for two separate jobs: pricing freight accurately and claiming the correct deduction on Schedule C.

How to calculate truck depreciation

To calculate truck depreciation, subtract salvage value from purchase price, then divide by useful life in years. The formula runs:

Each input carries a specific meaning:

• Purchase price: total cost basis, including sales tax, delivery, and any spec’d upfit
• Salvage value: realistic resale figure at the end of your trade cycle
• Useful life: years you intend to run the truck before replacement

Run a $180,000 Freightliner Cascadia with a $30,000 residual across 5 years and the truck sheds $30,000 annually, landing at $30,000 book value in year 6. That’s the number a lender wants. It is not the number the IRS wants, and the gap between the two trips up a lot of first-year owner-operators.

Three values describe the same truck at any moment. Book value comes from your depreciation schedule. Tax value comes from your Modified Accelerated Cost Recovery System (MACRS) schedule or your Section 179 election. Market value comes from the ATD/NADA Official Commercial Truck Guide or a recent auction comp. Quote the wrong one to your accountant and the return goes out wrong.

Which depreciation method fits your truck

Four methods apply to commercial trucks, and each produces a different first-year figure from identical inputs. Here is the same $180,000 tractor, $30,000 salvage, 750,000-mile expected life, run through all four:

Straight-line spreads the loss evenly and reads cleanly on a balance sheet. Declining balance recognizes that a tractor drops hardest in years one and two, which is closer to what actually happens at auction. Units of production ties the write-down to odometer readings, so a truck parked for six weeks with a blown aftertreatment system doesn’t depreciate on paper while it sits. For federal returns, MACRS is the default, and the 3-year General Depreciation System (GDS) rates run 33.33%, 44.45%, 14.81%, and 7.41%.

What is your truck’s depreciation cost per mile

Depreciation cost per mile equals annual depreciation divided by annual miles driven. At $30,000 per year across 120,000 miles, depreciation costs you $0.25 per mile.

That single figure belongs in your rate calculation alongside fuel, insurance, maintenance, and tolls. Drivers who price freight without it consistently underbid. A $2.10 per mile load looks workable until depreciation, fixed costs, and variable costs are all stacked against it.

Two truck depreciation calculator scenarios show why mileage matters more than years:

• 80,000 miles per year: $0.375 per mile
• 150,000 miles per year: $0.20 per mile

Running harder lowers depreciation per mile while raising it per year, since heavy mileage pulls resale value down faster. Regional haulers turning 80,000 miles annually hold value better at trade-in than long-haul units crossing 150,000.

How the IRS treats semi-truck depreciation

Trucks with a Gross Vehicle Weight Rating (GVWR) above 14,000 pounds (6,350 kg) face no per-vehicle Section 179 cap. Every Class 8 tractor clears that threshold at 33,000 pounds (14,969 kg) and up, which means the luxury auto limits under Section 280F never touch your equipment.

Current federal rules break down as follows:

• Section 179 limit: $2,560,000 total for tax years beginning in 2026, phasing out above $4,090,000 in purchases
• Bonus depreciation: 100% under Section 168(k), made permanent by the One Big Beautiful Bill Act (OBBBA) for property acquired and placed in service after January 19, 2025
• Business use test: more than 50% business use required for Section 179 or bonus depreciation
• MACRS class: 3-year GDS for over-the-road tractor units, 5-year for trailers and heavy general purpose trucks

The tractor-versus-truck distinction catches people. An over-the-road tractor unit is 3-year property. A straight truck or dry van trailer is 5-year property. Plenty of published guidance flattens both into a single 5-year rule, and that error costs real money in year one.

Depreciation recapture is the trap on the back end. Claim $180,000 under bonus depreciation, then sell the tractor two years later for $95,000, and that $95,000 comes back as ordinary income on Form 4797. Short trade cycles and full first-year expensing don’t pair well.

Report annual depreciation on IRS Form 4562. Full rules live in IRS Publication 946 and Publication 463.

What affects semi-truck resale value

Six factors move a Class 8 truck’s resale value more than anything else:

1. Odometer miles: units under 500,000 miles command a clear premium
2. Engine make: Detroit DD15, Cummins X15, and PACCAR MX-13 hold value differently by region
3. ECM hours: idle-heavy hours age a powertrain without adding miles
4. Maintenance records: documented service history adds thousands at trade
5. Spec and configuration: automated manual transmissions resell faster than manuals
6. Emissions equipment condition: a healthy aftertreatment system removes a buyer’s biggest fear

A Peterbilt 579 with 450,000 miles and complete service records outsells an identical unit at 480,000 miles with no paperwork. Buyers pay for certainty about what happened to the truck.

When to trade a truck instead of holding it

Trade the truck when annual maintenance cost exceeds annual depreciation. Year 4 on a typical Class 8 tractor brings a $30,000 paper loss against roughly $18,000 in repairs, so holding still makes sense. By year 7, an out-of-warranty engine overhaul at $25,000 against $12,000 of remaining annual depreciation flips the math.

Loan structure changes the calculation. Finance $180,000 over 60 months while the truck depreciates 40% in the first two years, and you sit in negative equity through roughly month 30. Selling during that window means bringing cash to closing.

Check your position against the ATD/NADA Official Commercial Truck Guide twice a year, then compare that figure against your amortization schedule.

Frequently Asked Questions