How much to put aside for quarterly taxes on one leased truck

Nobody withholds anything for you. The carrier pays your settlement, takes out fuel and the other deductions, and the rest is yours to sort out with the IRS four times a year. For one truck leased on, with a normal year, setting aside 20 to 25 percent of your profit covers the federal estimate for most people, and this post shows how to figure your own number instead of guessing.

The payment dates are April 15, June 15, September 15 and January 15. September 15 just passed. The next one is January 15, 2027, for the money you make from September 1 through December 31.

The four dates, and what each one covers

The "quarters" are not even quarters. That trips people up.

Payment due	Covers
April 15	January 1 – March 31 (3 months)
June 15	April 1 – May 31 (2 months)
September 15	June 1 – August 31 (3 months)
January 15	September 1 – December 31 (4 months)

So the June payment covers two months of work and the January payment covers four. If you save the same amount every week, the January payment is the one that needs the bigger pile behind it.

Work from the quarter's profit, not from the checks

Profit is what you keep after the truck eats. Start with everything the carrier paid you for the quarter — your share of the order gross plus fuel surcharge, before their deductions — then subtract what you spent to run:

• fuel, whether it came off the settlement on the card or you paid cash
• a driver's pay, if you have one, including reimbursements you paid back
• insurance
• repairs, tires, parts, oil changes
• tolls, scales, permits, plates, the ELD subscription
• everything else on the settlement the carrier held out — escrow is not an expense, but most of the rest is

One thing to be careful with: the truck payment is not all a deduction. The interest part is. The principal comes back to you as depreciation on a schedule your accountant sets. If you subtract the whole note, your profit will look lower than it is and your estimate will come up short. Ask your accountant what number to use for the truck, then use the same one all year.

Add up one quarter's settlements and one quarter's expenses and you have the profit. If you're keeping loads and settlements in one place, the profit and loss report will total a quarter for you instead of you running a tape on twelve weeks of sheets.

The two taxes, and the per diem that comes off first

There are two separate taxes on that profit.

Self-employment tax. This is Social Security and Medicare, both halves, because you're both the boss and the worker. The math is profit × 92.35% × 15.3%. That works out to about 14.13 cents on every dollar of profit.

Income tax. This one runs on profit minus half of the self-employment tax, at whatever bracket your household lands in. Plenty of one-truck households land in the 12% or 22% bracket. Use the higher of the two if you're not sure — better to have money left over in April.

Before either one, take your per diem. If you're the one driving and you're away from home overnight, you can deduct a meal allowance for each day out. The transportation industry rate is $80 a day, and 80 percent of it is deductible for drivers under DOT hours of service. So each full day away is worth $64 off your profit. The first and last day of a trip count at three-quarters, $60 a day, so $48 off.

That deduction comes off the profit before you figure either tax, which means it cuts the self-employment tax too.

Two things about per diem. It's for nights you were away from home in the truck. If you have a 1099 driver, the driver's nights go on the driver's own return, not yours. And you need a count you can show: a day-by-day record of where you were. Your loads already have it. Pickup date, delivery date, where the truck sat. Once a week, when the settlement comes in, write down how many nights you slept out and keep a running total for the quarter.

A worked quarter: $18,000 profit, 50 nights out

This is an example with round numbers. One truck, leased on, and you drive it. For the quarter, after fuel, insurance, the interest on the note and repairs, the profit is $18,000. You were away 50 days, and your household lands in the 12% bracket.

Without counting per diem:

• Self-employment tax: $18,000 × 92.35% = $16,623.00 × 15.3% = $2,543.32
• Half of that: $1,271.66
• Income tax base: $18,000 − $1,271.66 = $16,728.34
• Income tax: $16,728.34 × 12% = $2,007.40
• Total: $2,543.32 + $2,007.40 = $4,550.72

With 50 days of per diem:

• Per diem: 50 × $80 = $4,000 × 80% = $3,200
• Profit after per diem: $18,000 − $3,200 = $14,800
• Self-employment tax: $14,800 × 92.35% = $13,667.80 × 15.3% = $2,091.17
• Half of that: $1,045.59
• Income tax base: $14,800 − $1,045.59 = $13,754.41
• Income tax: $13,754.41 × 12% = $1,650.53
• Total: $2,091.17 + $1,650.53 = $3,741.70

The per diem saved $4,550.72 − $3,741.70 = $809.02 on this one quarter. That's the payoff for keeping a days-away count.

The example uses 50 full days at $80 to keep the arithmetic short. In real counting, the first and last day of each trip go in at $60, so a quarter of short trips home every weekend comes out a little lower than this.

One number a week, into its own account

$3,741.70 on $18,000 of profit is 20.8 percent. Over 13 weeks that's $287.82 a week.

That's the number to work with. Not a quarterly scramble — a transfer you make every Friday when the settlement hits, same as paying the driver. Open a second checking account at the same bank, name it TAX, and move the money the day the check clears. If you never see it in the operating account, you never spend it on a set of drive tires.

If you'd rather size it off each settlement instead of a flat weekly number, move 20 percent of every settlement deposit. On a slow week you move less, on a big week you move more, and it stays roughly right without you doing the math again.

When a quarter is bad, the next payment goes down. The year is taxed as one year, and the four payments are just installments toward that one number. A quarter where you replaced a motor and made nothing means you owe little or nothing for that quarter, and if you overpaid earlier in the year, you can pay less in January. There is also a rule that generally keeps you clear of penalty if you pay in at least as much as last year's total tax — 110 percent of it if your income was over $150,000. Whether that rule fits your year is a question for your accountant, and it's worth asking once.

What this estimate leaves out

On purpose, this runs high. It doesn't subtract the standard deduction, which is real money off your taxable income. It doesn't take the 20 percent deduction on qualified business income, which many owner-operators qualify for. It doesn't account for a spouse's W-2 withholding already covering part of the bill.

It also doesn't include state income tax, which depends on where you live and can be nothing at all or another several percent.

So the number you get from this is a set-aside, not a return. Your accountant figures the return, and if the set-aside was too big, you have money sitting in the TAX account in April. Nobody has ever been sorry about that.

This week

Add up your settlements and expenses from September 1 to today, so you know where the January 15 payment is headed before Thanksgiving. Count your nights away since September 1 off the load dates and write the number on the same page. Then open the second account, if you don't have one, and start moving 20 percent of every settlement into it this Friday. If your loads are already on file, the taxes guide shows where the same arithmetic is done for you, per diem nights and all.