Armin recently asked, "What percentage do you bill a client for unpaid invoices? And after how many days/months from due date do you start billing interest?"

I saw a couple of responses on Twitter. Victoria Pater charges 3% after 60 days, and Mindy Reznik opts for 1.8% after 30 days.

I stipulate that if the final invoice isn't paid within 30 days, a 5% "delayed payment" fee is charged. This initial 5% figure is then added upon each recurring 30 day period until the full amount is received.

Thankfully, I’ve yet to add the fee to an invoice, likely because I don’t send files until receiving full payment.

How do you deal with unpaid invoices?

Cole kindly pointed me toward these relevant pages: