Invoice Compliance Requirements

United States: invoices as tax records
United Kingdom: what every invoice must include

Invoice compliance depends on where you and your customer are. In the US, the IRS treats invoices as records you keep to support your tax return. In the UK, GOV.UK lists what every invoice must include, and HMRC sets out what a VAT invoice must show. In the EU, the VAT Directive sets out what has to appear on a VAT invoice. This page quotes each source and labels the jurisdiction. It's general information, not legal or tax advice, so ask your accountant how the rules apply to you.

Each source was opened on October 29, 2026. This page doesn't cover US state sales tax, other countries, or e-invoicing mandates.

United States: invoices as tax records

IRS Publication 583 (Starting a Business and Keeping Records) says:

"Supporting documents include sales slips, paid bills, invoices, receipts, deposit slips, and canceled checks."
"You should keep supporting documents that show the amounts and sources of your gross receipts."
On how long to keep them: "You must keep your records as long as they may be needed for the administration of any provision of the Internal Revenue Code. Generally, this means you must keep records that support an item of income or deduction on a return until the period of limitations for that return runs out."

This covers US federal tax records only. For state sales tax on your invoices, ask your accountant.

United Kingdom: what every invoice must include

GOV.UK's guide Invoices: what they must include says "Your invoice must include":

"a unique identification number"
"your company name, address and contact information"
"the company name and address of the customer you're invoicing"
"a clear description of what you're charging for"
"the date the goods or service were provided (supply date)"
"the date of the invoice"
"the amount(s) being charged"
"VAT amount if applicable"
"the total amount owed"

It adds: "You must use VAT invoices if you and your customer are VAT registered."

United Kingdom: VAT invoices

HMRC's VAT guide (VAT Notice 700), section 16.3.1 (page last updated June 25, 2026), says: "You must show the following details on any VAT invoice you issue". The list includes:

"a sequential number based on one or more series which uniquely identifies the document"
"the time of the supply (tax point)"
"the date of issue of the document (where different to the time of supply)"
"your name, address and VAT registration number"
"the name and address of the person to whom the goods or services have been supplied (your customer)"
"a description sufficient to identify the goods or services supplied"
"for each description, the quantity of the goods or the extent of the services, the rate of VAT, and the amount payable excluding VAT"
"the gross total amount payable, excluding VAT"
"the rate of any cash discount offered"
the total amount of VAT chargeable, which "must be expressed in sterling"
"the unit price (read paragraph 16.3.2)"

For more on numbering, see what an invoice number is.

Section 16.6.1 says "You can issue a simplified invoice if all of the following conditions exist", including "the value of the supply you are making is £250 or less" and "your customer agrees".

On how long to keep records, HMRC's Record keeping (VAT Notice 700/21) (last updated March 18, 2024) says: "Generally, you must keep all your business records for VAT purposes for at least 6 years."

European Union: VAT invoices

Article 226 of Council Directive 2006/112/EC (the VAT Directive, consolidated text of April 14, 2025) says that "only the following details are required for VAT purposes on invoices issued pursuant to Articles 220 and 221". The list includes:

"the date of issue"
"a sequential number, based on one or more series, which uniquely identifies the invoice"
the supplier's VAT identification number
"the full name and address of the taxable person and of the customer"
"the quantity and nature of the goods supplied or the extent and nature of the services rendered"
"the taxable amount per rate or exemption, the unit price exclusive of VAT and any discounts or rebates if they are not included in the unit price"
"the VAT rate applied"

On storage, Article 247 says: "Each Member State shall determine the period throughout which taxable persons must ensure the storage of invoices relating to the supply of goods or services in its territory and invoices received by taxable persons established in its territory." The consolidated text itself carries this notice: "This text is meant purely as a documentation tool and has no legal effect." So check the rules of the country you invoice in with your accountant.

E-invoicing

Some countries require invoices to be sent in a structured electronic format. For dates by country, see e-invoicing mandates. For getting ready, see how to prepare for e-invoicing. For adoption figures, see e-invoicing statistics.

Worked example: a UK VAT invoice

The figures here are a sample. A VAT-registered UK consultant bills a VAT-registered UK client for 3 days of work at £400 a day. GOV.UK's VAT rates page says "The standard VAT rate is 20%."

Net amount: 3 days × £400 = £1,200.
VAT at 20%: £1,200 × 20% = £240.
Total payable: £1,200 + £240 = £1,440.

Checked against Notice 700 section 16.3.1, the invoice shows:

Number and dates: the next number in its series (for example, INV-0107), the tax point and the date of issue.
Parties: for the consultant, "your name, address and VAT registration number"; for the client, "the name and address of the person to whom the goods or services have been supplied (your customer)".
The work: Consulting, 3 days with a unit price of £400 a day.
The amounts: the VAT rate (20%), the £1,200 net amount, any cash discount rate offered (none here), and the £240 of VAT in sterling.

Where Billed fits

Billed's invoice software page says: "Save your tax rates and settings once, and Billed calculates taxes automatically when you create invoices and estimates." It also says you can "Invoice customers in multiple currencies, choosing a different currency for each invoice or customer." Check that each invoice shows what your jurisdiction requires, and ask your accountant.

Frequently Asked Questions

What must a UK invoice include?

GOV.UK says "Your invoice must include" "a unique identification number", "your company name, address and contact information", "the company name and address of the customer you’re invoicing", "a clear description of what you’re charging for", "the date the goods or service were provided (supply date)", "the date of the invoice", "the amount(s) being charged", "VAT amount if applicable" and "the total amount owed". VAT-registered businesses selling to VAT-registered customers must use VAT invoices, which need more detail.

How long do I need to keep invoices?

It depends on the jurisdiction. For US federal tax, IRS Publication 583 says: "Generally, this means you must keep records that support an item of income or deduction on a return until the period of limitations for that return runs out." For UK VAT, HMRC says: "Generally, you must keep all your business records for VAT purposes for at least 6 years." In the EU, each Member State sets the storage period.

Does an EU VAT invoice need a sequential number?

For full VAT invoices, yes. Article 226 of the EU VAT Directive opens "Without prejudice to the particular provisions laid down in this Directive" and lists "a sequential number, based on one or more series, which uniquely identifies the invoice." For simplified invoices, Article 226b says Member States "shall require at least the following details", the first two being "the date of issue" and "identification of the taxable person supplying the goods or services". HMRC's VAT Notice 700 lists a sequential number for full UK VAT invoices. Ask your accountant which type applies to you.

When can a UK business issue a simplified VAT invoice?

HMRC's VAT Notice 700 (section 16.6.1) says "You can issue a simplified invoice if all of the following conditions exist", among them "the value of the supply you are making is £250 or less" and "your customer agrees". It needs fewer details than a full VAT invoice.

Do I need an accountant to check my invoices?

Rules differ by country, as the US, UK and EU sources on this page show. Ask your accountant which rules apply to your invoices.

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Invoice Compliance Requirements: US, UK and EU Basics