Invoice Checklist: 15 Things Every Invoice Needs

A client's accounts team will usually pay an invoice quickly if they can match it, approve it and pay it without asking you anything. Missing a single detail, such as a PO number, a tax ID or a due date, is one of the most common reasons an invoice sits unpaid. This invoice checklist lists the 15 things every invoice needs, explains why each one matters, and adds the extra fields required in the UK, India and Australia.

The 15-point invoice checklist

Use this as a pre-send check. Items 1 to 12 belong on practically every invoice; items 13 to 15 cover tax and payment, which is where most rejections happen.

Header and identification

1. The word "Invoice" (or "Tax Invoice"). It sounds obvious, but a document titled "Statement" or with no title can be filed in the wrong place. Some tax systems, including Australia and India, require the words "Tax Invoice" for GST invoices.
2. A unique invoice number. Each invoice needs its own number, ideally sequential (INV-2026-0147). Duplicate or missing numbers confuse both your books and the client's. See our guide to building an invoice numbering system.
3. The invoice date. The date you issue the invoice starts the payment clock for terms like Net 30.
4. The supply or delivery date. When the goods were delivered or the work was done. If you bill monthly, give the period, for example "Services 1–31 October 2026".

Who is billing whom

5. Your business name, address and contact details. Use your legal or registered business name, plus the trading name if different, a postal address, email and phone.
6. Your business registration details where required. Limited companies often need their registered company name, and many countries require a tax ID when you are registered for VAT, GST or sales tax. Our guide to tax IDs on invoices covers EIN, VAT, TRN and NTN.
7. The customer's legal name and billing address. Use the name of the entity that will pay, not just your contact's name. For companies, a person's name can go on an "Attn:" line.
8. The customer's reference or PO number. Not legally required in most places, but essential for many businesses. Without it, accounts payable cannot match your invoice to an approved order; more on that in our article about PO numbers on invoices.

What you are charging for

9. A clear description of each item. Specific enough that someone who was not involved can tell what they are paying for. "Website work" invites questions; "Homepage redesign, 2 revision rounds, delivered 4 Nov" does not. Our list of 40 invoice line item description examples has wording for most industries.
10. Quantity, unit and unit price. Hours, days, pieces, kilograms or square metres. Pick a unit that matches how you priced the job, following our guide to units of measure on invoices.
11. Line totals and a subtotal. Each line should multiply correctly (quantity × unit price), and the subtotal should be the sum of the lines.
12. Discounts and extra charges shown separately. Discounts, shipping, handling, travel or materials surcharges each get their own clearly labelled line.

Tax and payment

13. Tax rate and tax amount. If you charge VAT, GST or sales tax, show the rate and the amount for each rate. If you do not charge tax, a short note avoids questions (for example "Not VAT registered" or "Reverse charge applies").
14. The total amount due, with currency. The figure the client should pay, clearly labelled. If a deposit was paid, show it and the balance due. Add the currency code (USD, GBP, INR, AUD) when there is any chance of confusion.
15. Payment terms, due date and how to pay. State the terms (Net 30, Due on receipt) and the actual due date, plus bank details, a payment link or other accepted methods. A due date written as a calendar date removes any argument about when Net 30 started.

Sample invoice with every checklist item

Field	Example
Title	INVOICE
Invoice number	INV-2026-0147
Invoice date	12 November 2026
Supply period	1–31 October 2026
From	Northlight Studio Ltd, 14 Mill Lane, Leeds LS1 4AB, hello@northlight.example, VAT No. GB123456789
Bill to	Harbour Foods Ltd, Attn: Accounts Payable, 2 Quay Street, Hull HU1 1AA
PO number	PO-88213
Line 1	Monthly social media management, October 2026 – 1 month × £900.00 = £900.00
Line 2	Product photography, 24 edited images – 24 images × £25.00 = £600.00
Subtotal	£1,500.00
VAT 20%	£300.00
Total due	£1,800.00 GBP
Terms	Net 30 – due 12 December 2026
Pay to	Bank transfer: account name, sort code and account number

The company name, address and VAT number above are illustrative examples only.

Country-specific additions

The 15 items form a solid base, but tax-registered businesses usually need a few more fields. Our guide to invoice requirements by country goes deeper; here are the common ones.

United Kingdom

GOV.UK's list of what invoices must include covers a unique identification number, your and the customer's names and addresses, a clear description, the supply date, the invoice date, the amounts charged, VAT if applicable and the total owed. Limited companies must use the full registered company name, and if any directors are named, all of them must be. A full VAT invoice also needs your VAT registration number and the VAT rate and amount per item or rate.

India (GST)

A GST tax invoice adds your GSTIN, the recipient's GSTIN for registered buyers, the place of supply, HSN or SAC codes, and the CGST/SGST or IGST rate and amount for each item.

Australia (GST)

The Australian Taxation Office's tax invoice guidance requires your identity and ABN, the issue date, a description of what was sold, the GST amount (or a statement that the price includes GST) and, for sales of $1,000 or more, the buyer's identity or ABN.

United States

There is no federal invoice format, but if you collect sales tax, show it separately and keep invoices consistent with your state filings. Many corporate clients also require a completed W-9 on file before paying a new vendor.

The pre-send check: five minutes that save weeks

• Math: each line multiplies, the subtotal adds up, tax is on the right base.
• Names: the client's legal entity name matches their PO or contract.
• Dates: the due date matches the agreed terms and falls on a real calendar date.
• Bank details: current, and identical to what the client has on file. Changed details should be confirmed by phone, as they are a common fraud signal for buyers.
• Attachments: timesheet, delivery note or signed acceptance if the client requires it.
• File: PDF, named clearly, such as "INV-2026-0147 Northlight Studio.pdf".
• Recipient: the accounts payable inbox, not only your project contact. A short covering note helps; see our "please find attached invoice" email examples.

Optional extras worth adding

These are not on the core checklist, but they often speed up payment or prevent disputes:

• Late payment terms. A short line such as "Interest may be charged on overdue invoices" sets expectations. Check what local law allows; in the UK, for example, statutory interest applies to business-to-business debts.
• Deposit or payment history. If part was paid already, show the payment, its date and the balance due.
• Project or job reference. Useful for clients who run several projects with you at once.
• Contact for invoice queries. A named person and email for questions shortens the back-and-forth.
• A thank-you note. One line at the bottom costs nothing and keeps the tone friendly.
• Logo and consistent branding. It makes your invoice easy to spot in a pile of supplier documents.

Printable version of the checklist

#	Item	Done?
1	Title: Invoice / Tax Invoice	☐
2	Unique, sequential invoice number	☐
3	Invoice date	☐
4	Supply date or period	☐
5	Your name, address, contact details	☐
6	Registration and tax ID (if applicable)	☐
7	Customer's legal name and billing address	☐
8	PO or customer reference	☐
9	Clear line descriptions	☐
10	Quantity, unit and unit price	☐
11	Line totals and subtotal	☐
12	Discounts and extra charges	☐
13	Tax rate and tax amount	☐
14	Total due with currency	☐
15	Terms, due date and payment details	☐

Common invoice mistakes this checklist prevents

• Re-using an invoice number after editing a cancelled invoice.
• Billing a contact person instead of the company that owes the money.
• Vague descriptions that need a phone call before approval.
• No due date, so the invoice sits in a queue with no urgency.
• Tax charged without a tax ID, or a tax ID shown with no tax line.

For a longer list of errors and how to fix them, read 12 common invoice mistakes that delay payment.

Our invoice generator has a field for every item on this checklist, so nothing gets left off. It is free with no sign-up, and you can download each invoice as a print-ready PDF.