Is there a required invoice format in the US?
No federal law prescribes what an invoice must look like. What the IRS does require is that a business keeps records that support the income and expenses on its tax return, and it lists invoices among those supporting documents. [1] A clear invoice therefore serves two readers: your customer, who needs to know what to pay and by when, and your own books.
| Detail | Why it helps | In BillCrisp |
|---|---|---|
| Your business name, address and contact details | Lets the customer identify and contact you | Your details |
| Customer name and address | Matches the invoice to the right account in their books | Customer details |
| Invoice number and issue date | Gives both sides a unique reference for payment and records | Invoice number, Issue date |
| Due date and payment terms | States when payment is expected, for example Net 30 | Due date, Terms |
| Description, quantity and price of each item | Shows exactly what is being billed | Line items |
| Sales tax, where it applies | Shows the tax charged separately from the price | Tax rate per line, Sales tax total |
| How to pay | Bank, check or online payment instructions | Payment details |
| Your EIN, if a customer asks for it | Some business customers need it for their own reporting | EIN field |
Sales tax on US invoices
There is no federal sales tax. Sales tax is set by states, and often also by counties and cities, so whether you charge it, and at what rate, depends on what you sell and where. Many services are not taxable in many states, while most physical goods are. If you are not required to collect sales tax, leave the rate at 0% and BillCrisp shows no tax line.
- Set the rate per line, so a taxable product and an untaxed service can sit on the same invoice.
- Use the Prices include Sales tax option only if your prices already contain the tax; the summary then shows the taxable amount and the tax separately.
- Shipping has its own tax rate, because some states tax delivery charges and others do not.
EIN, SSN and Form W-9
An Employer Identification Number (EIN) is the federal tax identification number the IRS uses to identify a business. [2] Business customers that pay you may ask for your taxpayer identification number on Form W-9 so that they can file information returns. [3] Sole proprietors can often use either an EIN or a Social Security number for tax purposes; many prefer to give an EIN so that their SSN does not appear on business paperwork. You do not have to print any tax number on an invoice if no rule or customer requires it.
Tips for getting paid
- State clear terms such as Net 15 or Net 30, explained in our guide to invoice payment terms.
- Put a late fee in the Terms only if it was agreed in your contract; rules on late charges vary by state.
- Keep invoice numbers unique and in sequence; see invoice numbering.
Sources
- [1] Internal Revenue Service: What kind of records should I keep (accessed 2026-10-02)
- [2] Internal Revenue Service: Employer Identification Number (accessed 2026-10-02)
- [3] Internal Revenue Service: About Form W-9, Request for Taxpayer Identification Number and Certification (accessed 2026-10-02)