# Invoice Requirements Checklist for 2026

> An invoice checklist with the legal invoice rules for the UK, the EU, US businesses, and US federal contracts, plus payment terms.

## The invoice checklist

Use this checklist for each invoice. The first five groups apply to almost all businesses. The rules for your country and your industry, in the next sections, can add more items.

### Your business

- [ ] The legal business name exactly as registered
- [ ] Your trading name, if you use one ("Smith Consulting LLC d/b/a Rapid Results", where d/b/a means "doing business as")
- [ ] The business address
- [ ] A phone number and an email address for questions about invoices
- [ ] Your VAT (value-added tax) or GST (goods and services tax) number, if you are registered
- [ ] For US federal contracts, your taxpayer identification number (TIN), if the contract asks for it

### Your customer

- [ ] The full legal name of the customer, and the department for a large organization
- [ ] The billing address, and the delivery address if the goods went to a different place
- [ ] The name and email address of the accounts payable contact (the person who pays bills)
- [ ] The purchase order (PO) number or the contract number, if the customer uses one

### Invoice number and dates

- [ ] A unique invoice number from a sequential series, never used again
- [ ] The invoice date
- [ ] The date or period of supply ("Services: January 1 to 31, 2026"), if it is different from the invoice date
- [ ] The due date as a calendar date, not only "Net 30" (payment within 30 days)

### Line items

- [ ] A specific description of each item or service (model, SKU product code, or deliverable)
- [ ] The quantity and the unit (hours, units, or days)
- [ ] The unit price or rate before tax
- [ ] The total for each line, rounded to two decimal places

### Totals and payment

- [ ] The subtotal before tax
- [ ] Each tax with its rate and amount
- [ ] Discounts, deposits, or retentions on separate lines
- [ ] The total amount due, with the currency
- [ ] The payment terms and the payment methods that you accept, with the details for each method
- [ ] Late payment terms, if you use them and if local law permits them

### Before you send

- [ ] The line totals, subtotal, tax, and total are correct
- [ ] The invoice goes to the accounts payable contact as a PDF with a clear file name ("Invoice_2026-0147_Acme_Corp.pdf")
- [ ] You kept a copy with the date sent

![Invoice creation process: gather business info, add client details, itemize services, calculate totals, verify and send](/assets/blog/invoice-requirements/diagram_gather-business-info.webp)

## What the rules require in each country

The checklist above is good practice everywhere. In some countries, some of the items are legal requirements.

### United Kingdom

GOV.UK lists the items that [every invoice must include](https://www.gov.uk/invoicing-and-taking-payment-from-customers/invoices-what-they-must-include):

- A unique identification number
- Your company name, address, and contact information
- The company name and address of the customer
- A clear description of what you charge for
- The supply date and the invoice date
- The amounts, the VAT amount if applicable, and the total that the customer owes

A sole trader (a self-employed person) must also show his or her own name and any business name. A sole trader who uses a business name must also give an address for legal documents. A limited company must use its full name as it shows on its certificate of incorporation. If you and your customer are both registered for VAT, you must send a VAT invoice. A VAT invoice shows [your VAT number and the VAT as a separate amount](https://www.gov.uk/vat-record-keeping/vat-invoices).

### European Union

The European Commission lists the contents of a full [VAT invoice](https://taxation-customs.ec.europa.eu/taxation/vat/vat-businesses/vat-invoicing_en):

- The date of issue and a unique sequential number
- The full names and addresses of the supplier and the customer
- The VAT number of the customer, if the customer must pay the tax
- A description and the quantity of the goods or services
- The unit price before tax
- The date of supply or payment, if it is different from the invoice date
- The VAT rate, the VAT amount, and the VAT for each rate or exemption

Under the reverse charge, the customer pays the VAT instead of the supplier. In that case, the invoice must include the words "reverse charge." Each member state also has its own rules. Read the rules of the country that you send invoices from.

### United States

For sales between private businesses, three sources decide what an invoice must show. They are the sales tax rules of your state, your contracts, and the accounts payable policy of your customer. The IRS lists invoices as [records that support your gross receipts](https://www.irs.gov/businesses/small-businesses-self-employed/what-kind-of-records-should-i-keep). The IRS generally tells you to keep tax records for [at least three years](https://www.irs.gov/businesses/small-businesses-self-employed/how-long-should-i-keep-records), and longer in some cases.

Sales tax rates and the list of taxable services change from state to state, and often from city to city. Show the rate that you used on the invoice. Make sure that the rate is correct with the revenue department of your state.

### US federal government contracts

The Prompt Payment clause, [FAR 52.232-25](https://www.acquisition.gov/far/52.232-25), lists the contents of a proper invoice:

- The name and address of the contractor
- The invoice date and the invoice number
- The contract number
- The description, quantity, unit of measure, unit price, and extended price
- The shipping and payment terms
- The name and address of the contractor official who receives the payment
- The name, title, phone number, and mailing address of the person to contact about a defective invoice
- Your TIN, if the contract requires it
- Your banking information for electronic funds transfer
- Other information that the contract asks for

Read the invoice section of your contract. It can add more items.

## Payment terms in plain words

Payment terms tell the customer when to pay. The invoice date starts the payment period. At the end of the period, the invoice is paid or late.

![Invoice payment timeline: the invoice is issued and starts the payment clock, the customer pays within the terms window, and the invoice is either paid or late, when penalties can apply](/assets/blog/invoice-requirements/diagram_invoice-payment-lifecycle.webp)

| Term | Meaning |
|---|---|
| Due on receipt | The customer pays when the invoice arrives |
| Net 15, Net 30, Net 60 | The full amount is due 15, 30, or 60 days after the invoice date |
| 2/10 Net 30 | The customer gets a 2% discount for payment in 10 days. If not, the full amount is due in 30 days. |
| Retention (construction) | The customer holds back a part of each payment until the project is complete |

Write the calendar due date next to the term. "Invoice date January 15, Net 30, due February 14" leaves nothing for the customer to calculate.

Your contract sets late fees, and local law limits them. In the US, each state has rules on the interest that you can charge. Make sure that your rate is legal in your state before you print it on the invoice. In the UK, a business can claim [statutory interest of 8% plus the Bank of England base rate](https://www.gov.uk/late-commercial-payments-interest-debt-recovery/charging-interest-commercial-debt) on late payments from another business. A different rate in the contract replaces this rate.

## Items for some industries

Some industries add items to the invoice:

- Construction: A retention line ("Less 10% retention"). For progress billing (invoices for each stage of a long project), add a schedule of values with the percent complete for each line.
- Consulting and freelance work: A project reference and an hourly breakdown by task.
- Government contracts: The contract number and the identifiers that the contract asks for (see FAR 52.232-25 above).
- Medical billing: Procedure codes, diagnosis codes, and the claim format of the payer. These documents are claims, not usual invoices, and they follow the rules of the payer.

## Mistakes that delay payment

Look for these mistakes before you send an invoice:

1. No PO number. Many large organizations match each invoice to a PO before they pay it.
2. A vague description. "Services rendered" makes accounts payable ask what the invoice is for.
3. Math errors. The line items do not add up to the subtotal, or the tax is on the wrong amount.
4. A wrong tax rate, or tax on an exempt item. The customer must stop and correct the invoice.
5. The wrong recipient. The invoice stays with a project manager who cannot approve it.
6. An edited invoice. If an invoice is wrong after you send it, void it and send a new invoice with a new number. Keep the void copy.

## Use this checklist with Claude or ChatGPT

Claude or ChatGPT can do a first review of an invoice against this checklist. Paste the checklist, the rules for your country from the section above, and the invoice text. You can also attach the PDF. Ask for an answer for each item.

```text
Below is an invoice checklist, the invoice rules for my country, and an
invoice. Check the invoice against every item and answer Pass, Fail or
Not applicable, quoting the part of the invoice that shows it.
Recalculate each line total, the subtotal, every tax line and the total,
and show the math. List everything missing or wrong, most serious first.

CHECKLIST AND RULES:
[paste the checklist and the rules for your country]

INVOICE:
[paste the invoice]
```

Make sure that each finding is correct before you change the invoice. The assistant can miss an error, invent an error, or calculate wrong. Calculate again each amount that the assistant questions.

Hide bank details and tax numbers before you paste the invoice. Also read the data settings of your workspace. For tax rates, tax treatment, and limits on late fees, your accountant or your tax authority gives the final answer. Use the AI review to find missing items, not to decide tax questions.

A docs portal with Ask AI
and support tickets

Connect a repository, or describe your product to start. Each docs site has search, Ask AI, an API console, an MCP server and support tickets.

Publishes from GitHub on every push

Works with Mintlify repositories

API console from your OpenAPI file

MCP server and llms.txt for AI agents

Ask AI and support tickets

Analytics for people and AI agents

Start Free →

Questions? Ask AI in our docs
No card required.

## Frequently Asked Questions

### What is the difference between an invoice and a receipt?

An invoice asks for payment. A receipt shows that the customer paid. Send the invoice before the payment. Send a receipt after you get the money, if the customer asks for one.

### What is a pro forma invoice?

A pro forma invoice is a preliminary invoice that you send before the sale is final, for example as a quote or for a customs declaration. It shows the expected items and prices, but it does not ask for payment. Do not use it in place of the final invoice in your tax records.

---

[View the canonical page](https://revdoku.com/blog/invoice-requirements/) · [Browse llms.txt](https://revdoku.com/llms.txt)