Tax Planning for Contractors: CPA Advice That Saves Real Money

Every dollar you earn as a contractor gets taxed twice before you see it. Income tax takes its cut. Then self-employment tax takes another 15.3%, covering both the employer and employee portions of Social Security and Medicare, because when you work for yourself, you’re both.

Most contractors overpay. They’re too busy running crews and chasing permits to sit down and plan, so deductions go unclaimed, entity structures go unexamined, and quarterly payments turn into April surprises.

Shanli Liu, CPA and founder of Freedom Folio, a virtual tax practice based in Boston, works with contractors, including plumbers, remodelers, and house flippers. She recently helped one $1.2 million remodeling company cut its taxable income by 19% in two seasons through better planning alone.

“The most significant tax issues for contractors stem from poor recordkeeping,” Liu says. But recordkeeping is just the start. The real savings come from entity structure decisions, expense timing, and systems that keep you compliant year-round instead of scrambling every April.

Here’s the playbook.

1. Choose the right entity structure

This is the single biggest tax lever most contractors never pull, or pull at the wrong time.

Most small contractors start as an LLC taxed as a sole proprietor. That’s fine early on. But as profits grow, the 15.3% self-employment tax on your net income starts adding up fast. On $100,000 in net income, that’s roughly $14,130 in self-employment tax alone, all before income tax.

An S corp election changes how that income is taxed. You pay yourself a reasonable salary (subject to payroll taxes), then take remaining profits as distributions that aren’t subject to self-employment tax. For a $100,000 income, that can mean saving $5,000 to $10,000 annually.

But Liu cautions against jumping too early. “A lot of clients come to me and say, ‘My business made about $100K this year, maybe I should become an S corp,'” she says. “But there’s additional cost associated with being an S corp owner: separate tax filings, administrative fees, payroll setup costs.”

Her threshold? Contractors netting around $130,000 per year should evaluate whether the tax savings outweigh the added complexity.

“There’s no cookie-cutter solution for everyone,” Liu says. “Consult with a CPA before you listen to some TikToker telling you the S corp is the way to go.”

Your move: If you’re netting under $130K, an LLC taxed as a sole proprietor is likely fine. Above that, ask your CPA to run the numbers on an S corp election. The math should show clear savings after accounting for payroll costs and additional filing fees.

2. Plug the three common contractor tax leaks

Liu sees three patterns that drain contractor profits every year.

Leak 1: Track glove box receipts 

Fuel, fittings, dumping fees. If it doesn’t make it into your accounting software, your CPA never sees it, and it never becomes a deduction. “My rule of thumb is if it rolls, it digs, or it drills, there’s probably a paper receipt somewhere in their glove compartment,” Liu says.

The fix is simple: Snap a photo of every receipt the day you get it using a receipt capture app (more on that in Section 5), and make it a habit before you start the truck.

Leak 2: Time your expenses 

When you buy matters almost as much as what you buy. A $65,000 mini-excavator purchased on December 15 counts as a deduction on this year’s return. Wait until January 2 and the same write-off shifts to next year. That timing decision matters when your income varies year to year, because you want the deduction in the year your tax bracket is highest, therefore reducing your tax burden.

When you buy a piece of equipment, the IRS normally expects you to deduct the cost a little at a time over several years. That’s called depreciation. But two provisions let you skip the wait and deduct the full cost in year one.

Section 179 lets you choose how much to deduct upfront. Buy a $55,000 van and you could write off $30,000 this year, then spread the rest over future returns. “It’s like a dimmer switch,” Liu says. “You control how much to expense.” The One Big Beautiful Bill Act raised the limit to $2.5 million, far more than most contractors will ever need in a single year.

Bonus depreciation is the all-or-nothing version. If the asset qualifies, the IRS automatically deducts 100% in year one. The same law reinstated that 100% rate for property placed in service after January 19, 2025.

That flexibility matters, which leads to Liu’s next point.

Leak 3: Avoid overloading deductions

The temptation in a banner year is to load up on equipment purchases for massive write-offs. But that leaves you with no deductions in a down year. “Don’t load up all your deductions in one year and then have nothing,” Liu says. “Save some for the future.”

The math: Liu gives this example: A contractor buys a $55,000 work van and finances it at 6%, paying about $1,063 a month. A Section 179 first-year write-off at a 24% marginal tax rate yields roughly $11,000 in tax savings, enough to cover about 10 months of the loan payment.

Your move: Before any equipment purchase over $10,000, call your CPA. Ask: Should I buy now or wait? Section 179 or bonus depreciation? How does this affect next year’s tax picture?

3. Don’t miss subcontractor deductions

Subcontractor payments are deductible, but documentation gaps can cost you.

“I always tell my contractor clients, the best rule of thumb is before you pay somebody, ask them to fill out a W-9,” Liu says. If a subcontractor won’t provide one, you can still deduct the payment as long as you have an invoice and can document that you attempted to collect the W-9.

But here’s the risk: Failing to issue a 1099 puts the hiring contractor on the hook for IRS penalties. The payment is still deductible, but you’re exposed.

Your move: Make W-9 collection mandatory before the first payment. Store them digitally. Issue 1099s for any subcontractor you pay $600 or more in a calendar year.

4. Master quarterly payments with the 25% sweep

Estimated quarterly taxes are where most contractors fall behind. The IRS requires estimated payments if you expect to owe $1,000 or more, with deadlines in April, June, September, and January. Miss them and you may face penalties.

The problem is that construction cash flow is wildly unpredictable. “They’re always the last one to get paid,” Liu says. “They don’t even know most of the time when the cash is going to be coming in.”

Her solution is dead simple: Open a separate bank account. Call it your tax account. Every time you get paid, sweep 25% of net receipts into the reserve.

“Don’t buy equipment or supplies with everything in your bank,” Liu says. “Put money aside for your tax bill first.”

This approach works because it sidesteps the problem of books that aren’t current enough to produce accurate P&L projections. You don’t need a perfect profit-and-loss statement to set aside 25% automatically. When quarterly payments come due, the cash is already there.

Your move: Open a dedicated savings account this week. Set up an automatic transfer, or manually sweep 25% of every payment received into the reserve. Pay your quarterly estimates from this account.

5. Set up recordkeeping that works from the truck

A massive deduction won’t help if your CPA never sees the receipt. Liu recommends a specific tech stack built for contractors running between job sites:

QuickBooks Online with job cost class tracking (~$60/month). This gives you accounting software that ties expenses to specific projects, which is critical for both tax accuracy and tracking project profitability.

Dext or QuickBooks Receipt Snap for receipt capture. “The difference between these and your phone camera is that Dext integrates directly with QuickBooks,” Liu says. “It automatically uploads and captures the expense, so the bookkeeper gets notified.” No more shoeboxes.

MileIQ for mileage documentation. The IRS expects continuous mileage records, not a year-end estimate. “Start the app when you start your engine,” Liu says. Log which job the trip was for, and at year-end, hand your CPA the total.

Meals: If you’re buying lunch for your crew so they stay on the job site, that’s a business deduction, up to 50% of the cost. But only if you record it. Track who ate, the business purpose, and keep the receipt.

Your move: Download QuickBooks, a receipt capture app, and MileIQ this week. The setup takes an afternoon. The savings compound for years.

6. Build a tax team that works year-round

Most contractors see their accountant once a year, during tax season. By then, it’s too late to plan. You’re reacting to what already happened.

“With the traditional firm, you don’t even see your CPA until tax season,” Liu says. “You don’t even know how much tax you’ll owe until your CPA tells you. With us, we send quarterly estimates. We communicate regularly.”

Liu recommends checking in with your CPA at least twice a year: once mid-year, once before year-end. That mid-year check-in is where the real planning happens. Is your entity structure still right? Should you accelerate or defer a major purchase? Are your quarterly payments on track?

She also shared a cautionary tale: A client unknowingly registered for a sales tax account in Massachusetts, never filed returns (even zero returns), and 10 years later received an $85,000 penalty notice. Liu’s team got the penalties abated, but the client still paid $2,000 and endured months of stress. Filing zero returns would have prevented the entire ordeal.

A proactive CPA catches issues like that before they snowball.

What to look for in a CPA:

• Experience with construction clients specifically
• Willingness to communicate quarterly, not annually
• Proactive tax planning, not reactive tax preparation
• Understanding of Section 179, bonus depreciation, and contractor-specific deductions

And consider how the rest of your financial setup supports tax planning. When your cash flow is predictable, quarterly payments and year-end planning get dramatically easier. Offering customer financing through platforms like Acorn Finance helps with that. You get paid upfront when the project starts while your customer spreads payments over time, which also makes it easier to close bids that might otherwise stall on price. That predictable income stream makes it far simpler to sweep 25% into your tax reserve, fund quarterly payments on time, and give your CPA accurate numbers to work with.

Where to start

This week:

• Open a dedicated tax reserve bank account and start the 25% sweep.
• Download QuickBooks, a receipt capture app, and MileIQ.
• Collect W-9s from every active subcontractor.

This month:

• Schedule a mid-year check-in with your CPA (or find one who specializes in construction).
• Pull your last two years of tax returns. What’s your effective tax rate? Are you structured correctly?

Before year-end:

• Review any planned equipment purchases with your CPA. Decide Section 179 vs. bonus depreciation.
• Confirm your quarterly payments are on track to avoid penalties.
• If you’re netting over $130K, evaluate an S corp election for next year.

The bottom line

Tax planning happens throughout the year, not in April. Setting aside cash automatically, timing purchases strategically, documenting everything, and working with a CPA who understands your business is what separates a manageable tax bill from a painful one.

“Good recordkeeping and good accounting is the foundation to everything,” Liu says. “The bigger you get, the harder it is to change bad habits.”

Start with the 25% sweep. Build from there. The savings compound, and so do the habits.

Want steadier cash flow to make tax planning easier? See how Acorn Finance helps contractors get paid upfront while giving customers flexible payment options.