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Key takeaways
- A good invoice answers four questions at a glance: who is billing whom, for what, how much and by when.
- Goods invoices lead with quantity and unit price. Service invoices lead with a clear description of the work and the period.
- Always quote the purchase order number if the buyer gave you one. It decides whether the invoice is paid on time.
- Every number in these examples is made up for illustration.
Free PDF and Excel: Invoice template with three worked examples. Get it below
Example 1: an invoice for goods
Made-up details. Supplier: Northgate Packaging Ltd. Buyer: Harlow Foods. Invoice HF-2026-0214, dated 3 March 2026, purchase order PO-88231, due 2 April 2026 (net 30).
| Description | Qty | Unit price | Amount |
|---|---|---|---|
| Kraft carton 300 x 200 x 150 mm | 2,000 | 0.62 | 1,240.00 |
| Printing, one colour, per carton | 2,000 | 0.11 | 220.00 |
| Delivery to Harlow Foods, Dock 3 | 1 | 95.00 | 95.00 |
| Subtotal | 1,555.00 | ||
| Sales tax at 8 percent | 124.40 | ||
| Total due | 1,679.40 |
Example 2: a fixed-fee service invoice
Made-up details. Supplier: Bright Path Consulting. Buyer: Harlow Foods. Invoice BP-0067, dated 30 April 2026, statement of work SOW-2026-04, milestone 2 of 4.
| Description | Amount |
|---|---|
| Supplier data clean-up, milestone 2: validation of 6,000 records, accepted 28 April 2026 | 7,500.00 |
| Total due, payment terms net 15 | 7,500.00 |
Free PDF and Excel
Invoice template with three worked examples
A clean invoice layout, three filled-in examples and a pre-send checklist.
- Invoice layout
- Three worked examples
- Pre-send checklist
- Excel invoice with automatic totals
Example 3: an hourly invoice
Made-up details. Supplier: Dana Okafor, freelance analyst. Buyer: Harlow Foods. Invoice DO-012, covering 1 to 31 May 2026, purchase order PO-88377.
| Date range | Task | Hours | Rate | Amount |
|---|---|---|---|---|
| 1 to 14 May | Spend report build | 22.5 | 80.00 | 1,800.00 |
| 15 to 31 May | Dashboard handover and training | 14.0 | 80.00 | 1,120.00 |
| Total due | 36.5 | 2,920.00 |
Fields every invoice needs
| Field | What goes in it | Why it matters |
|---|---|---|
| Invoice number and date | A unique number and the issue date. | Matching and duplicate checks depend on them. See invoice numbers. |
| Seller and buyer | Legal names, addresses, tax numbers. | Needed for tax and for the vendor master. |
| PO or contract reference | The buyer's order number or the SOW. | The most common reason for a rejected invoice is a missing PO. |
| Line detail | Description, quantity, unit price, line total. | Each line should be checkable. |
| Tax | Rate and amount, shown separately. | Keeps the buyer's tax return right. |
| Total and currency | The amount due and the currency. | No decoding needed. |
| Payment terms and details | Due date, how to pay, bank details. | The buyer pays faster when it does not have to ask. |
Little things that speed payment
- Put the due date on the invoice, not just "net 30".
- Send it to the address the buyer's accounts payable asked for.
- Use the buyer's item names where you can.
- One PDF per invoice, not a bundle.
- Add remittance details, including the reference the buyer should quote.
If your work is a service, see the service invoice guide. For international sales read commercial invoice. If you are in India, use the GST invoice guide.
- Number and date are on it.
- PO or SOW reference is included.
- Lines add up, tax is separate.
- Due date is written out.
- Payment details are correct.
- It went to the right inbox.
Last checked: 19 October 2026. Examples are made up. Tax and format rules differ by country, so check local requirements.
Frequently asked questions
What should an invoice include?
A number, a date, seller and buyer details, a description of each item or service, quantities and prices, tax, the total and the payment terms.
Is there a standard invoice format?
No single worldwide format. The content is similar everywhere, but some countries add required fields for tax invoices.
Do I need a PO number on an invoice?
If the buyer issues purchase orders, yes. Many buyers reject invoices that lack one.
Can I write an invoice by hand?
Yes, if it contains the required content. A template makes it neater and avoids arithmetic slips.
How soon should I send an invoice?
As soon as the work is done or the goods ship. The earlier the invoice, the earlier the clock starts.