original research

Payment terms move the deadline, not the behaviour

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

  • 53,095 paid invoices from 180 businesses, 2007 to August 2026
  • Invoices due on receipt are paid in 15.9 days on average
  • Net 30 invoices are paid in 47.2 days on average
  • Share paid by the due date: 39.1% on due-on-receipt, 42.3% on Net 30
  • Invoices the client opened are paid 6.9 days sooner than those never opened
  • Invoices in the study with a late fee set: zero

How long do invoices actually take to get paid?

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.

Do longer payment terms mean clients pay on time more often?

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.

Does shortening payment terms actually get you paid sooner?

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.

Days to payment by payment terms

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.

Billbooks invoice data, 53,095 paid invoices from 180 businesses, 2007 to August 2026.
Payment terms Invoices Businesses Mean days to pay Paid by due date
Due on receipt31,79415915.939.1%
Net 71,4184818.648.5%
Net 155,2765426.947.1%
Net 3012,6206847.242.3%

Does a client opening an invoice mean they pay it sooner?

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.

Three questions this data could not answer

Stated because a study that only reports what worked is not worth trusting.

Whether late fees get invoices paid faster

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.

Whether automatic reminders speed up payment

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.

How payment speed varies by industry

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.

Method

  • Source. Billbooks invoice records, 2007 to August 2026.
  • Population. Invoices with at least one recorded payment. Days to payment is measured from the invoice date to the first payment date.
  • Excluded. Sample and demonstration invoices, and any invoice where days to payment computed as negative or over 365, which indicates a data-entry error rather than a slow payer.
  • Reporting threshold. A figure is published only where the bucket contains at least 25 distinct businesses and at least 100 invoices. Thirty-two payment-term buckets fell below that and were suppressed, not rounded or merged.
  • Aggregation only. No individual business, client, invoice or amount was extracted. Every query is a grouped count or average.

Limitations

  • 180 businesses is a modest base. The invoice count is large because some businesses issue many invoices, so the effective sample is smaller than 53,095 suggests.
  • The window is long. Payment norms between 2007 and 2026 are not constant.
  • These are Billbooks customers, which is not a random sample of businesses. Firms that adopt invoicing software may already chase payment more actively than those that do not.
  • Terms are what was recorded on the invoice, which is not always what was negotiated.

Anyone is welcome to cite these figures with attribution to Billbooks and a link to this page.

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