We looked at 53,095 paid invoices from 180 businesses. Roughly four in ten are paid by the due date, and that barely changes whether the terms are due-on-receipt or Net 30. Giving a client thirty days does not make them more likely to pay on time.
Key figures
Every row below met the reporting threshold of at least 25 distinct businesses and 100 invoices. Terms used by fewer businesses than that were excluded rather than reported.
| Payment terms | Invoices | Businesses | Mean days to pay | Paid by due date |
|---|---|---|---|---|
| Due on receipt | 31,794 | 159 | 15.9 | 39.1% |
| Net 7 | 1,418 | 48 | 18.6 | 48.5% |
| Net 15 | 5,276 | 54 | 26.9 | 47.1% |
| Net 30 | 12,620 | 68 | 47.2 | 42.3% |
The figures above cover almost two decades. To see how invoices behave now, we looked separately at the recent window: 8,483 invoices from 112 small businesses, last 24 months (September 2024 to September 2026). The same rule applies: a figure is shown only where at least 25 businesses contribute to it.
Most invoices count as late, but mostly because most are due on receipt, which makes any payment after the day of sending late by definition. The better measure is days to be paid: a week or two for the typical invoice, and only a small share drift into the range where the money starts to look lost.
What to do: Plan cash on the basis that most invoices will land a week or two after they go out. Treat the few still open a month past due as a separate problem, and pick up the phone for those.
Most invoices say due on receipt because it is the default setting and few owners ever change it. By its own terms nearly every one of those invoices is late, but that is a matter of definition, not speed: across the full study, due on receipt was the quickest of all the common terms to be paid.
What to do: Keep terms short if you want the money sooner; longer terms add days to the wait almost one for one without making clients more punctual. A short fixed date, such as 7 days, gives you a date to point to when you chase, at the cost of a few days in the full study.
For many small businesses one client is close to half the year, and repeat customers carry the rest. That is a comfortable position until the big client pays late, and then everyone the business pays waits too.
What to do: Work out what share of last year your largest client was. If it is half or more, decide now what you would do if their payments slipped by a month, before it happens.
The typical invoice is modest, but unpaid ones add up, and a large part of what looks owed can simply be payments nobody recorded. Money arrives on ordinary working days, and very few owners keep their costs in the same place as their invoices.
What to do: Once a month, mark off every payment that has arrived and look at what is really still owed. Recording expenses next to invoices is what lets you see profit rather than just income.
Source: Billbooks invoice data, 8,483 invoices from 112 small businesses, September 2024 to September 2026 (aggregate only, figures shown only where 25+ businesses contribute).
Stated because a study that only reports what worked is not worth trusting.
A late fee was set on zero of 67,634 invoices. Not a small number, none. With no invoices carrying a late fee there is no comparison to make, so this study says nothing about whether late fees work.
The raw comparison suggests invoices with reminders switched on are paid more slowly. We do not believe that is cause and effect, and we are not publishing it as a finding. Reminders are not assigned at random: a business turns them on for clients it already expects to chase, so the setting marks expected lateness rather than creating it. Separating the two needs a controlled comparison, which this data cannot provide.
Billbooks does not record an industry for a business, so this cannot be measured. Estimating industry from another field would be inventing the dimension rather than measuring it.
Anyone is welcome to cite these figures with attribution to Billbooks and a link to this page.
The study in forty seconds: due on receipt against Net 30, and why longer terms only move when late begins.
Across 53,095 paid Billbooks invoices, the average is 25 days from issue to payment. It varies by terms: invoices due on receipt are paid in 15.9 days, Net 15 in 26.9 days and Net 30 in 47.2 days. Around four in ten are paid by the due date.
No. In this study the share of invoices paid by the due date was 39.1% on due-on-receipt terms and 42.3% on Net 30, a difference of three percentage points across a thirty-day gap in terms. Longer terms move the deadline rather than improving compliance.
Yes, almost one for one. Net 30 invoices were paid at 47.2 days on average and due-on-receipt invoices at 15.9 days. The terms differ by 30 days and the outcome differs by 31, so time granted is added to the wait rather than absorbed by faster behaviour.
Invoices opened by the client were paid in 19.3 days against 26.2 days for invoices never opened, a gap of 6.9 days. This is a correlation and not proof of cause: opening an invoice and paying it promptly are both signs of an engaged client.
Most of them, on paper. In Billbooks invoice data, about 65% of paid invoices arrive after the due date, largely because most invoices are due on receipt. When an invoice is paid late, the typical delay is 11 days; one in four late invoices is 28 or more days late.
Not on the day, but sooner than on longer terms. In the Billbooks invoice payment study, invoices due on receipt were paid in 15.9 days on average, against 47.2 days for Net 30. Because the due date is the day the invoice is sent, almost every one counts as late, which is not the same as slow.
Often close to half. In Billbooks invoice data covering the last 24 months, for the typical small business, the single biggest client accounts for 43% of a year's billing (58 businesses with two or more clients). In 45% of small businesses, one client accounts for half or more of a year's billing (58 businesses).