Net 30 is a payment term on an invoice that means the client has 30 days from the invoice date to submit full payment. It is one of the most common payment terms in freelance and B2B (business-to-business) transactions. Other common variations include Net 15 (15 days), Net 60, and Net 90. For self-employed individuals, understanding and clearly communicating payment terms on every invoice is essential to managing cash flow. A client on Net 60 terms means waiting two months to get paid, which can strain finances if you're not prepared.