Invoicing is the part of freelancing people underestimate most. The work is done; you think you're finished. The invoice is the work that turns finished work into money — and if the invoice is sloppy, late, or missing the right details, the money comes 30 days later than it should. Compound that across a year of clients and you've financed your customers' cash flow with your rent.
This guide covers the mechanics: what goes on an invoice, what terms to pick, how to send it, when to follow up, how to chase overdue ones without burning the relationship, and the specific language changes that empirically cut days off payment time.
The legal minimum for a US freelancer invoice isn't as strict as you'd think — the IRS doesn't mandate a specific format. But the following 10 fields are the floor for getting paid on time and defending the invoice if there's a dispute:
"Net 30" means the invoice is due 30 days after issue. It's the US B2B default because it matches most corporate AP cycles. For freelancers, Net 30 is often too generous.
| Terms | Meaning | When it fits |
|---|---|---|
| Due on receipt | Payable immediately | Small projects, retail clients, existing trust |
| Net 7 | Due in 7 days | Individual clients, fast projects |
| Net 14 | Due in 14 days | Small businesses, project completion invoices |
| Net 15 | Due in 15 days | The middle ground — not default but increasingly common |
| Net 30 | Due in 30 days | Mid/enterprise B2B (their AP cycle) |
| Net 60 / 90 | Longer terms | Large enterprise only; negotiate up-front fee if pushed here |
| 2/10 Net 30 | 2% discount if paid in 10 days, else full in 30 | When you need cash speed and can afford the discount |
Rule of thumb: match the client's size. An enterprise client won't honor Net 7 no matter what the invoice says; their system is locked on Net 30 or worse. A small business or individual will pay on Net 14 without blinking.
The best payment terms are the ones that match the client's AP system, enforced by a deposit up front so the remainder is small enough that 30 days don't matter.
Standard freelance practice for any project over $2,000: 50% deposit up front, 50% on delivery. This does two things:
For projects over $10,000, a 50/25/25 (start/midpoint/delivery) or milestone-based split is standard. Never invoice the whole thing at the end — that's a year-one freelancer mistake.
The day the work ships, not the end of the month. A common mistake: "I'll batch invoices on the 1st." The math says send on delivery:
Across a year of freelance work, same-day invoicing pulls roughly one full month of receivables forward. For a freelancer doing $100k/yr, that's $8,000+ of cash flow unlocked.
Three delivery methods, in order of payment speed:
Assumed terms: Net 30. Aggressive but not abrasive:
| Timing | Action | Subject line |
|---|---|---|
| Day of invoice | Send invoice with a one-line email | Invoice #127 from [Your Name] — [Project] |
| Day 14 (halfway) | Friendly check-in — 'does your team need anything?' | Quick check-in re: Invoice #127 |
| Day 30 (due) | Polite reminder — attach invoice PDF again | Invoice #127 is due today — attached again for reference |
| Day 31 | Firm follow-up — ask for ETA | Invoice #127 past due — any update on timing? |
| Day 45 | Escalation — CC AP department if enterprise | Invoice #127 — 15 days overdue — please advise |
| Day 60 | Late fee applied (if contractually allowed) + formal letter | Invoice #127 — collection notice |
Short, warm, assumes nothing's wrong:
Factual, no apology, assumes no issue:
Firmer, asks for a specific date:
A late fee in the invoice terms isn't legally binding unless it's in the signed contract/SOW. The invoice is a bill, not a contract amendment.
Typical late-fee language for the contract:
The enforceability varies by state (some cap late fees), but the number on the contract rarely gets disputed. It's a motivation tool more than a revenue source.
After day-60 with no response, the realistic options are: send to a collection agency (they take 25–40% + damage the relationship), small claims court (feasible up to $5–$10k depending on state, $75–$500 in filing fees + your time), or write it off as a business loss (bad-debt deduction on Schedule C).
The write-off math: if your marginal federal + state rate is 30% and SE tax is 15.3%, a $3,000 bad-debt write-off recovers roughly $1,360 in tax reduction. Not the full $3,000 — but often more than a collection agency would net after their cut.
For retainer clients, the Net 30 cadence is asking to be exploited — send invoice, wait 30 days, remind, wait, receive — every single month.
The upgrade: Stripe billing / recurring invoices on autopay. Client sets up ACH or card once, you bill automatically on the 1st, payment lands on the 3rd. Net 2, not Net 30.
This is where per-client pricing models stop making sense. If you have 15 retainer clients and FreshBooks is charging you per-client, you're paying for a feature (recurring billing) that Stripe does natively.