Split into installments

What it's for

A big expense and the question «how much a month is that»: the washing machine, the trip, the course fee, the deposit to get back from friends. Here you type the amount and how many times, and out comes each instalment. It's the simplest division there is, and that's exactly why the value of this page is in what's written around it.

There's no interest here, and in real life there almost always is

The arithmetic is a plain division: amount ÷ number of instalments. That works for what really does split into equal parts: a present among friends, a shared household expense, a payment by instalments agreed with whoever is selling you something without adding anything.

It doesn't work for a loan. There the instalment isn't the amount divided by the months: inside it are the interest, the arrangement fee, the per-instalment collection charge and the insurance, and the number that tells the truth isn't the nominal rate but the APR, which includes them all. A «zero interest» deal with a 4-euro fee on each of twelve instalments is not at zero interest. The right sum is done by Real APR.

The cent left over

A hundred euros in three instalments makes 33.33 each, and three times 33.33 is 99.99: one cent is missing. That isn't a rounding error on this page, it's that some amounts don't split into equal parts. In practice it's settled by putting the difference on the last instalment (or the first), and that's what banks and finance companies do: the final instalment is nearly always a few cents different from the others.

Nearby tools

If the instalments carry interest, the pages are Real APR and Mortgage payment; to find out how long it takes to clear a debt paying a fixed sum there is Debt payoff time. If instead the expense has to be split among several people who paid for different things, that's Group expenses.