Self-Employed Billing: How to Handle Invoices When You Start Hiring Subcontractors
The first time you pay another person for work you brought in, something quietly shifts. You’re still self-employed, still running your own thing, but now you’re also the one signing the checks. Most freelancers don’t notice the change until tax season, when they realize their records don’t hold up. The work was fine. The paperwork wasn’t.
Missing documents cost real money. Not in penalties for bad deliverables, but in disallowed deductions, late-filing fees, and scrambling to reconstruct what you paid to whom. Here’s what actually changes when you start hiring help, and what you need to do about it from day one.
What changes when you become a paying party
In the US, the Internal Revenue Code (specifically IRC §6041 and §6041A) requires you to file Form 1099-NEC for any non-employee contractor you pay $600 or more during the calendar year. You send one copy to the contractor by January 31 and one to the IRS. Miss the deadline and penalties stack up fast $60 per form if you’re 30 days late, rising to $130, and up to $310 per form for intentional disregard. For a freelancer who hired three subcontractors and forgot, that’s nearly a thousand dollars in avoidable penalties.
In the UK, there’s no equivalent 1099 form, but HMRC requires every outgoing payment to be recorded as part of your Self Assessment. You’ll deduct subcontractor costs as allowable business expenses but only if you can produce the invoice and proof of payment. No record, no deduction.
Either jurisdiction, the principle is the same: the moment money leaves your account for someone else’s labor, the paperwork clock starts.
What is self-billing, and when should you use it
Self-billing is when you issue the invoice on behalf of your subcontractor, instead of waiting for them to send one to you. You prepare it, they accept it, you pay for it.
It makes sense in a few specific situations: recurring contractors you work with every month, offshore workers whose invoicing standards don’t match what your bookkeeper needs, and anyone who reliably forgets to send paperwork until you chase them three times. If you’ve ever paid someone and then spent a week asking for “a proper invoice for my records,” self-billing solves that.
It creates risk in other situations. Don’t use it with one-off contractors where there’s no relationship yet, or anyone you anticipate a dispute with. Once you’re issuing the invoice, you own the accuracy of what’s on it.
For either approach standard or self-billed you can generate a compliant invoice in under a minute at gdoc.io’s free online invoice generator. No signup, and the downloaded PDF is sufficient documentation for both IRS and HMRC records.
Self-billing rules: UK vs US
The UK regulates self-billing formally. HMRC requires a written self-billing agreement signed by both parties before you issue the first invoice, and the agreement has to be reviewed every 12 months (or whenever the contractor’s VAT status changes). The invoice itself must be marked “self-billing” and include the contractor’s VAT number if they’re registered. Skip the agreement and HMRC can disallow the VAT recovery.
The US has no formal self-billing regulation. Payee-prepared invoices are widely accepted in practice, and the IRS cares about what was paid, to whom, for what work rather than who typed up the document. That said, having the contractor countersign or email confirmation of the invoice amount is smart. It removes any argument later about whether the payment was authorized.
What to collect before the first payment
This is the part most first-time hirers skip, and it’s the most expensive thing to fix after the fact.
In the US, you need a completed Form W-9 from every subcontractor before you pay them. The W-9 gives you their legal name, address, and taxpayer identification number everything you need to file the 1099-NEC in January. If you pay someone without a W-9 on file and they refuse to provide one, you’re legally required to withhold 24% of their payment as backup withholding and remit it to the IRS. You can grab a W-9 template here.
In the UK, collect the contractor’s Unique Taxpayer Reference (UTR) number and confirm their VAT registration status. If they’re VAT-registered, you’ll need their VAT number on every invoice to reclaim input VAT.
Day-one checklist for any subcontractor, anywhere:
- Legal name and business address
- Tax ID (W-9 for US, UTR for UK)
- Payment details (bank info, PayPal, etc.)
- Written agreement covering scope, rate, and payment terms
Get these four things before money moves. Not after.
What a valid subcontractor invoice must contain
Whether you receive it or self-bill it, a valid invoice needs: a unique invoice number, the issue date, both parties’ legal names and addresses, a clear description of the work, the amount charged, and payment terms. UK invoices from VAT-registered contractors also need the VAT number, VAT rate, and VAT amount shown separately.
The most common mistakes on invoices from subcontractors: no invoice number (makes it untraceable in an audit), missing date (can’t prove which tax year it belongs to), vague descriptions like “consulting services” (won’t survive scrutiny), and no address on either side. Any of these can get an invoice disqualified as a tax record, which means the expense gets disallowed.
If you’re receiving a sloppy invoice, ask for a corrected one before you pay. It’s ten times easier than fixing it at year-end.
How long to keep everything on file
IRS: three years is the standard statute of limitations for audits. That extends to six years if you underreported income by more than 25%, and indefinitely if the IRS suspects fraud. Seven years is the safe floor.
HMRC: six years from the end of the tax year the records relate to. Non-negotiable.
For every subcontractor payment, keep four things together: the invoice (standard or self-billed), proof of payment (bank statement, PayPal receipt, wire confirmation), the contract or written agreement, and the W-9 or UTR confirmation. A folder per contractor per year works fine digitally is acceptable in both countries as long as the records are complete and legible.
The freelancers who get through audits cleanly aren’t the ones with the fanciest systems. They’re the ones who collected the right documents on day one and kept them somewhere they could find five years later.
