What to include on an invoice

The parts every invoice needs

Most unpaid invoices are not refusals. They are invoices that someone put aside because something on them was unclear, and then forgot. The fix is unglamorous: say exactly who is billing whom, for what, how much, and by when.

At minimum, every invoice you send should carry the following.

• The word "Invoice" and a unique invoice number
• Your business name, address, phone and email
• The customer's name and the job address, if they differ
• The date you issued it, and the date payment is due
• A line for each item of work, with quantity and unit price
• The total, with tax shown separately if you charge it
• How to pay — bank details, cheque payee, or payment link
• Your payment terms in plain words ("Payment due within 14 days")

The three details that cause most disputes

In practice, arguments cluster around the same three things, and all of them are avoidable at the moment you write the invoice rather than six weeks later on the phone.

Vague line items. "Labor — $480" invites the question "for what?". "Labor, 4 hrs @ $120 — drain line excavation and backfill" does not. The extra fifteen seconds of typing is the cheapest insurance you will ever buy.

Parts without specifications. Writing "valve — $68" tells the customer nothing about whether they got a good one. Writing "1/2 in. quarter-turn brass shut-off valve" documents that you fitted the right part, and it protects you if someone else works on the job later.

Costs that appear without warning. Permit fees, after-hours premiums, disposal charges and minimum call-out fees are all legitimate. They become disputes when the first time the customer sees them is on the bill. Mention them when you quote, then give each its own line so the total is explainable.

Payment terms that actually get honoured

Terms work when they are specific. "Net 30" means nothing to a homeowner. "Payment due by 15 November" does.

Be explicit about what happens after the due date, too — a late fee you never mentioned is very hard to collect, while one printed on the original invoice usually just makes people pay on time. Check what your local rules allow before you set a rate.

For larger jobs, split the payment. A deposit before you order materials, a balance on completion, and both stated on the invoice, removes the awkward conversation entirely because the schedule was agreed up front.

Numbering, and why it matters more than it looks

Use sequential numbers with no gaps. It makes your own records searchable, it makes an accountant's job faster, and in many places it is a legal expectation for business records.

A simple scheme is a prefix and a running number — 2026-001, 2026-002. Avoid dates alone, because two jobs on the same day collide, and avoid anything derived from the customer's name, because you will eventually need to issue them a second invoice.