When to send an invoice: on delivery, in advance or at month end

Dev finishes a website fix for a client in Toronto on the 3rd of the month. He does his invoicing on the last day of each month, so the invoice goes out on the 31st, with 14 days to pay. The money arrives in mid-November, six weeks after the work. Nothing went wrong: the client paid on time. The four weeks before the invoice was sent were simply added to the wait.

The clock starts when the invoice arrives

Payment terms count from the invoice date, and most accounts teams only start the process when the invoice is in front of them. Every day between finishing the work and sending the invoice is a day added to the wait. It is the one delay that is entirely in your hands. It also helps the client: the work is fresh, the person who asked for it is still around to approve it, and the budget is still open.

Pick the timing that fits the work

On delivery: the same day

For most one-off work, send the invoice the day you deliver. Make it part of handing over: the files, the goods, the keys and the invoice in the same message or the same visit. If you wait for the client to confirm they are happy, ask for that confirmation by a date, or the invoice waits on a reply that may never come.

In advance: before you start

Asking for payment up front is normal for small jobs, rush work, events with a fixed date, and new clients you have not worked with. It removes the risk of not being paid at all. For larger work, a deposit with the balance on delivery is the usual middle ground. See deposit invoices and, for long projects, billing in stages.

Month end, or a fixed day

For ongoing work, one invoice a month on the same day is easier for both sides than one per task. Decide whether it covers the month ahead or the month just finished. Billing ahead suits fixed monthly fees, like a retainer. Billing in arrears suits work that varies, such as hours. If your client pays suppliers on a fixed run, like the 25th, ask for the cut-off date and send your invoice before it, so you are not held to the next month.

Deadlines some countries set

Where VAT or GST applies, the law often sets the latest date for issuing an invoice. A few examples at the time of writing:

• UK: a VAT invoice is usually due within 30 days of the date of supply.
• EU: for a sale to a business in another member state, by the 15th day of the month after the sale.
• India: for services, within 30 days of supply in most cases; for goods, at or before the time they are removed or delivered.

Those are the latest dates, not good targets. Check your tax office's rules for your own case, especially for advances, which in some countries create a tax point before the invoice.

Sending on a weekend or at night

An invoice sent late on a Friday is read on Monday among everything else. If you can, send during your client's working hours, early in the week. It is a small effect beside sending it on time at all, but it costs nothing. For clients abroad, mind the time zone.

Make the habit easy

• Write the invoice as a draft when you start the job, and issue it the moment you finish.
• Agree the timing on the quote: “50% on booking, 50% on delivery”, or “invoiced on the 1st for the month ahead”.
• Put the due date on as a date, so the client knows exactly when.
• Keep payment terms short. Sending fast and then giving 60 days undoes the gain. See payment terms.

The short version

• The payment clock starts when the invoice arrives, so send it as soon as you can.
• One-off work: invoice on delivery, the same day.
• Small jobs and new clients: ask for payment, or a deposit, before you start.
• Long projects: invoice in stages. Ongoing work: the same day each month.
• Some countries set a latest date for VAT or GST invoices. Treat it as a limit, not a target.