Late Payment and Cash Tied Up Calculator

On the figures this ships with, a business invoicing $300,000 a year on 30-day terms is paid in 62. The interest on the money that is late comes to $2,104 a year.

The number nobody works out is the one behind it: $26,301 of money already earned, sitting in other people’s bank accounts. Pulling the payment days back by twenty releases $16,438 — once, immediately, permanently, without making a single extra sale. That is roughly eight times the annual interest everybody was worrying about.

This is why a business can be profitable and still short of cash, and it is why chasing invoices is worth more than it feels like it is worth.

The page keeps two things apart that usually get run together. Money tied up by the terms you agreed to is not somebody behaving badly — it is a decision you made, and shortening it is a conversation to have at the start of a relationship. Money tied up by lateness is a different conversation, in the middle of one. Both figures are shown, separately.

It also refuses to offer you days you cannot have. If you set a target of pulling back more days than they are actually late, the page says so: chasing cannot reach past the terms you agreed to, and beyond that point the lever is a shorter payment term rather than a firmer email. Those rows in the table carry no figure at all.

Chasing is costed too. The hours go in and are compared against what the chasing would release, because a page that treated your time as free would be doing the same thing to you that the late payers are.

It does not tell you to charge interest, it is not a debt collection tool, and it makes no claim about what you are entitled to. It is arithmetic on your own invoicing, done on your own machine.

Save as many versions as you like and put any two side by side, figure against figure, with the better one on each line marked and the difference in its own column. That screen is the one that decides things, and it is the part a free calculator cannot do at all. Save one per client and the worst payer is obvious from the list.

One HTML file. No account, no subscription, no internet needed. Opens on Windows, Mac and Android; the readme explains the extra step on iPhone and iPad, where Apple blocks JavaScript in downloaded files and every tool of this kind is affected.

Everything lives in your browser on your device. Nothing is uploaded, which is why it works offline and why nobody else can see your figures — and it also means clearing your browsing data deletes it. The tool does not pretend otherwise: the header shows how long since your last export at all times, turns amber after three days and red after seven, and export is one click that produces a plain file you keep.