Payroll for Contractors: A Complete Guide

Why Payroll Is Different for Contractors

Payroll for a contracting business is more complex than for most other industries — and the consequences of getting it wrong are more severe. You're dealing with:

• • Variable hours driven by job schedules, weather, and seasonality
• • Workers who move between job sites, sometimes across state lines
• • Prevailing wage requirements on public works projects
• • A mix of W-2 employees and 1099 subcontractors on the same job
• • Overtime that's hard to predict and expensive to miscalculate

The IRS and Department of Labor scrutinize construction payroll heavily. Misclassification of employees, missed deposit deadlines, and overtime errors are among the most common enforcement targets. Understanding the rules — and having systems to follow them consistently — is not optional for any contractor with employees.

The other reason payroll matters so much: it's your largest cost. Labor typically represents 30–50% of a contracting job's total cost. If your payroll process is inefficient, inaccurate, or non-compliant, you're exposing your largest cost center to both legal and financial risk.

Employees vs. 1099 Subcontractors

The first question in contractor payroll: who is an employee vs. a 1099 independent contractor? This matters enormously because employees require full payroll tax withholding, and the IRS scrutinizes contractor classification closely.

Someone is likely an employee if:

• • You control when, where, and how they do their work
• • They work exclusively or primarily for you
• • They use your tools and equipment
• • They're paid hourly or by the day, not by the project
• • You set their hours and schedule

Someone may be a 1099 subcontractor if:

• • They operate their own business and work for multiple clients
• • They supply their own tools and set their own methods
• • They're paid per project (not hourly)
• • They're free to accept or reject work
• • They carry their own liability insurance

Misclassifying employees as 1099s is one of the most common and costly mistakes in construction. The IRS can assess back payroll taxes (both employee and employer portions), plus penalties of up to 100% of unpaid taxes in egregious cases. When in doubt, consult a CPA or employment attorney in your state.

Important: the fact that a worker signs a 1099 agreement or asks to be treated as a contractor doesn't protect you. The IRS applies an economic reality test based on how the relationship actually works — not what the paperwork says. If a worker functions as an employee, they're an employee regardless of what the contract calls them.

Payroll Taxes: What You Owe

When you pay employees, you're responsible for withholding and remitting several taxes. As an employer, you pay some taxes directly (not withheld from the employee) and collect others on the employee's behalf:

As an employer, your out-of-pocket payroll tax expense is the employer's share — roughly 7.65% of wages (SS + Medicare match) plus FUTA/SUTA. On a $30/hour employee, plan for ~$2.30–$2.50/hour in employer payroll taxes alone, plus your state's SUI rate (typically 1–3% on new employers).

Real payroll cost example: an employee earning $30/hour, working 40 hours/week (biweekly pay period):

This additional ~10–12% employer cost is why your labor cost in estimates must include more than just the wage rate. A $30/hour worker actually costs you $33–$35/hour all-in before any overhead allocation.

Overtime Rules for Contractors

Under federal law (FLSA), non-exempt employees must be paid 1.5× their regular rate for all hours over 40 per workweek. Most construction workers are non-exempt and subject to overtime.

State overtime rules vary and often exceed federal minimums:

• • California: OT after 8 hours/day AND after 40 hours/week; double-time after 12 hours/day
• • Nevada: OT after 8 hours/day (for employees earning under 1.5× minimum wage)
• • Alaska, Colorado: Daily overtime rules apply
• • Most other states: Federal rules apply (weekly only, 40+ hours)

Key rule: overtime is calculated on the workweek (Sunday–Saturday, or another fixed 7-day period you set), not the pay period. If an employee works 50 hours this week and 30 hours next week on biweekly payroll, you still owe 10 hours of OT this week — you cannot average across the two weeks.

For contractors, overtime typically spikes during busy seasons, large pushes to finish a job before a deadline, and when crews are short-staffed. The most common overtime mistake: a supervisor telling workers "we'll make up the hours later" — that's not how overtime law works.

Overtime budgeting tip: when estimating job labor costs, assume 5–10% of hours will be overtime on average. Build OT into your labor cost projections, not just straight-time wages.

Choosing a Pay Period

The pay period affects your admin burden, your cash flow, and your employees' satisfaction. Common pay periods for contractors:

• Weekly — Employees get paid every Friday. Highest admin burden (52 pay runs/year). Preferred by field workers who live paycheck to paycheck. Good for high-turnover trades.
• Biweekly — Every two weeks (26 pay periods/year). Most common in construction. Good balance of admin ease and employee satisfaction. Aligns cleanly with workweeks for OT calculation.
• Semi-monthly — 1st and 15th (or similar). 24 pay periods/year. Creates complexity with overtime — workweeks don't align with semi-monthly dates, so OT must be tracked weekly even though paychecks go out twice a month.
• Monthly — Once per month. Easiest admin, but difficult for field workers. Less common in trades where workers need cash flow.

Most contracting businesses use biweekly. It reduces admin vs. weekly while still giving employees regular, predictable paychecks. Note: some states require minimum pay frequency — verify your state's rules before choosing.

Workers' Compensation Insurance

Workers' compensation is required in nearly every state for any contractor with employees. It covers medical expenses and lost wages if an employee is injured on the job. For contractors, workers' comp rates are among the highest of any industry — construction work is physically dangerous.

Workers' comp is calculated as a rate per $100 of payroll, varying by job classification code. Typical rates:

These rates are why workers' comp should be part of your overhead calculation, not an afterthought. A roofing company with 5 employees at $50K wages each could easily pay $50,000–$100,000 per year in workers' comp premiums alone. That's overhead cost that must be recovered in your prices.

Some contractors use "pay-as-you-go" workers' comp, which ties premiums directly to actual payroll rather than estimated payroll. This improves cash flow and eliminates year-end audits that result in surprise additional premiums.

Prevailing Wage and Certified Payroll

If you work on any government-funded projects (federal, state, or local), you may be subject to prevailing wage laws. The Davis-Bacon Act covers federally funded construction; most states have their own "Little Davis-Bacon" laws for state-funded work.

Prevailing wage requirements include:

• • Paying minimum wage rates set by the Department of Labor for each trade in your geographic area (these rates are often significantly above market rates)
• • Providing specific fringe benefits (health insurance, pension, vacation) at set rates — or paying them as cash supplements
• • Submitting weekly certified payroll reports (federal WH-347 form) to the project owner or general contractor
• • Maintaining detailed records of hours, wages, and job classifications for each worker on the project
• • Posting prevailing wage notices at the job site

Certified payroll requirements are document-intensive. You must submit a report every week showing every worker, their classification, hours, wage rates, and deductions. Many general contractors require this before releasing payment.

Prevailing wage violations carry severe penalties: back wages, debarment from future public contracts, and in some cases criminal prosecution. If you're bidding public work, use a payroll service or software that specifically supports certified payroll compliance.

Tax Deposit Schedule and Filing Requirements

Payroll taxes must be deposited with the IRS on a schedule based on your total tax liability in the prior lookback period:

• Monthly depositors: Deposit by the 15th of the following month. For businesses with under $50,000 in total payroll taxes in the prior 12-month lookback period.
• Semi-weekly depositors: If taxes exceeded $50,000 in the lookback period. Payday on Wednesday/Thursday = deposit by following Wednesday. Payday on Friday/Sat/Sun/Mon/Tue = deposit by following Friday.
• Next-day rule: If you accumulate $100,000+ in payroll taxes on any day, you must deposit the next business day regardless of your normal schedule.

Quarterly and annual filing requirements:

• • IRS Form 941 — Quarterly payroll tax return (due April 30, July 31, October 31, January 31)
• • IRS Form 940 — Annual FUTA return (due January 31)
• • W-2s to employees — Due January 31 each year
• • 1099-NEC to contractors — Due January 31 for any sub paid $600+ in the year
• • State payroll returns — Varies by state; most are quarterly

Missing deposit deadlines results in failure-to-deposit penalties of 2–15% of the unpaid amount. Use EFTPS (Electronic Federal Tax Payment System) for IRS deposits. Most states have their own electronic deposit portals.

Common Payroll Mistakes Contractors Make

The most expensive payroll mistakes in contracting — and how to avoid them:

• 1. Misclassifying employees as 1099s.

  Already covered above — but it bears repeating because it's the most common issue. The IRS has a voluntary compliance program (VCSP) that reduces penalties if you come forward before being audited. If you've been doing this, fix it proactively.

• 2. Not withholding based on current W-4s.

  Employees update W-4s when they have life changes. If you're still using old W-4 information, you may be under-withholding — creating tax bills for your employees at year-end and potential employer penalties.

• 3. Calculating overtime incorrectly.

  If you pay bonuses, shift differentials, or non-discretionary performance pay, those must be included in the "regular rate" used to calculate overtime — not just the base hourly wage. Many contractors use the wrong base rate for OT and end up underpaying.

• 4. Paying workers off the books.

  Cash pay under the table creates massive liability: unpaid payroll taxes, potential criminal exposure, and workers' comp violations. If a worker paid off-books gets injured, you have no coverage and full personal liability.

• 5. Missing deposit deadlines.

  Payroll tax deposits are time-sensitive. The penalties escalate quickly and are non-negotiable. Use automated deposits through EFTPS and set calendar reminders for every deposit due date.

• 6. Not tracking job-site time accurately.

  For job costing to work, you need accurate time records per job site, not just total hours worked. Contractors who rely on end-of-week employee memory for time cards routinely have inaccurate job cost data.

Payroll Software vs. Full-Service Payroll

Contractors typically handle payroll one of three ways:

• Manual/spreadsheet — Calculating taxes by hand. Works for a solo owner-operator, but becomes untenable the moment you hire employees. High error rate.
• Payroll software (like a contractor platform with built-in payroll) — Automates calculations, tax tables, and filings. You run payroll and the software handles the math. Much faster than manual, integrates directly with job costing and overhead tracking.
• Full-service payroll bureau (ADP, Paychex, etc.) — Full outsourcing. They handle deposits, filings, W-2s. More expensive, and many don't integrate well with contractor-specific job costing. Good if you have 15+ employees with complex payroll needs.

For most small-to-mid contractors (1–15 employees), integrated payroll software is the right choice. It costs less than a full-service bureau, automates the math, and keeps payroll data connected to your job costs and overhead tracking — which matters when you're pricing jobs.

The key question to ask about any payroll software: does it handle all 50 states? Does it auto-calculate overtime correctly? Does it tie timesheet data to job costs? Does it generate the payroll tax liability reports you'll need for deposits and filings?

Payroll and Job Costing: The Connection

Payroll and job costing are not separate systems — they should be the same system. Every hour a worker spends on a job is a job cost that flows through your payroll. If they're separated, you lose the ability to know your true cost per job.

Contractors who track payroll and job costs in separate systems (payroll in QuickBooks, job tracking in a spreadsheet) constantly struggle with mismatched numbers. The hours on a timesheet don't match the hours on the job — because they're being tracked in different places.

The right approach: timesheets that capture which job site each hour was worked at, flowing through payroll for wage calculation, and simultaneously flowing into job cost reports. When a job is complete, you can see exact labor cost vs. estimated labor cost with no manual reconciliation.

This is also how you improve your estimates over time. If your bids assume 40 labor hours and jobs consistently run 50 hours, your estimates are wrong. Accurate time tracking against jobs is the data that tells you where your estimates are off — and how to fix them.