How to Invoice as a Contractor: Independent and Trade Contractors

"Contractor" covers two quite different people: the independent contractor (a developer, designer or consultant billing a company instead of being on its payroll) and the trade contractor (a plumber, electrician, roofer or builder). The basics are shared, but the details differ. This guide covers both.

What every contractor invoice needs

• Your legal name or business name, address, phone and email
• License number, if your trade or state requires it on invoices
• Client's name and billing address
• Job site address, if different
• Invoice number and invoice date
• Description of the work, with dates
• Labor and materials, itemized (for trades)
• Subtotal, tax (if applicable), total
• Payment terms and due date
• How to pay

Independent contractors billing companies

If you're a 1099 contractor in the US, or self-employed elsewhere, working for a business:

Match their paperwork. Ask at the start: who do invoices go to, do they need a PO or project code, do they need you set up as a vendor first. Many companies can't pay until you're in their system.

Send a W-9 once, separately. US clients need your taxpayer identification number to issue a 1099-NEC, but it doesn't go on the invoice. Send the W-9 through a secure channel when you're onboarded. From payments made in 2026, clients generally only have to issue a 1099-NEC once they've paid you $2,000 or more in the calendar year (up from $600). More in 1099 contractor invoicing.

Describe deliverables. "Backend API development: payments module, sprint 14 (2–13 Sept)" beats "Development services."

Bill on a rhythm. Weekly or biweekly for hourly work; per milestone for fixed-price work. See invoicing for hours worked.

Trade contractors billing homeowners and businesses

Separate labor and materials. It's clearer, and in some US states materials are taxable while labor isn't (or vice versa), so the split matters for tax too.

Description	Qty	Rate	Amount
Replace 50-gal water heater: labor	4 h	$95.00	$380.00
50-gal gas water heater (model XYZ)	1	$780.00	$780.00
Fittings, valves, venting kit	1	$96.00	$96.00
Haul away old unit	1	$45.00	$45.00
Permit fee (pass-through)	1	$65.00	$65.00
Total			$1,366.00

Get a deposit before buying materials. For bigger jobs, 10–50% up front is common. Some states limit how much a home improvement contractor can take as a deposit (California's limit, for example, is 10% of the contract price or $1,000, whichever is less), so check your state's rules. See deposit invoices.

Document change orders. When the customer asks for extra work, write it down with a price and get a signature or email approval before doing it. On the invoice, list change orders as separate lines with their reference.

Include warranty terms if you offer them: "Labor guaranteed for 12 months from completion."

Larger jobs: progress billing and retainage

On commercial or multi-week jobs, invoice as you go:

• Progress billing: bill a percentage of the contract as each stage completes.
• Retainage: the client holds back a percentage (often 5–10%) until the job is finished and signed off.
• Lien waivers: in the US, you may need to provide conditional or unconditional lien waivers with invoices or payments.

All of this is covered in construction progress billing.

Payment terms that work for contractors

• Homeowners: due on completion or Net 7. Individuals pay what's in front of them.
• Small businesses: Net 14 to Net 30.
• General contractors and large companies: often Net 30 to Net 60, sometimes "pay when paid." Know this before bidding.

Always state late payment terms. For trades in the US, also know your mechanic's lien rights and deadlines in your state; they're one of the strongest tools you have, but they have strict notice requirements that often start before you finish the job.

Common mistakes

• Invoicing weeks after completion
• Lumping everything into one line: "Plumbing work: $1,366"
• No change order paperwork for extras
• Missing the job site address, so the client can't match it
• Not keeping receipts for materials

For a fuller list, see common invoicing mistakes.