How Budget Control works
Setting a monthly limit, how spending is measured against it, and why the site never blocks anything.
Setting a limit
The monthly limit is a single number you choose, stored in this browser alongside your records. It is entirely optional: with no limit set, the page simply reports your recorded spend for the month.
The limit is not tied to a currency by the site. Record in whatever currency you actually use and keep it consistent, because the totals are plain arithmetic on the numbers you enter.
How usage is measured
Usage is the sum of the spent field on records dated within the current calendar month, compared against the limit. Returns are excluded on purpose. A budget describes what you are willing to send out; netting off returns would turn a fixed limit into one that moves whenever a return arrives, which defeats the purpose.
Going over the limit
If recorded spend exceeds the limit, the page states the amount by which it does, in neutral wording, once. There is no warning sound, no red banner across the site, no repeated prompt and no attempt to make you feel watched. The site also cannot stop any spending, and does not pretend to.
What you do with that information is up to you: review the entries, adjust the limit so it reflects what you actually intend, or stop for the month. If a limit is regularly exceeded by a large margin, the responsible use page is worth reading.