Are interest-free installments worth it?

With high inflation, often yes: you pay with money that is worth less. But know how much you already have committed before adding another.

What if I paid foreign-currency purchases with my own currency?

Record how much left your account and for how much of the foreign amount: that keeps the rate you really paid.

Credit card installments: how much you pay each month and until when

By Dionel Azar, creator of Busimy · Updated October 31, 2026

To keep card installments under control, record each purchase with its installment (3 of 12) and the amount per installment. With that you know what you pay this month, next month, when each one ends and how much is committed in total. Each installment is spending of the month you pay the card, not of the month you bought it.

The problem with installments

A purchase in 12 installments looks cheap the day you make it. But when five or six pile up, a big part of each month's pay is already committed before it arrives, and it is hard to see until when.

What you always want to know

How much you pay in installments this month and next.
Which purchases you finish paying this month (and how much frees up).
How much money is committed in total, and until which month.
How much is left on each purchase.

Is it spending of the month you bought or the month you paid?

To understand where your money goes each month, count each card purchase in the month you pay the statement: that's when the money really leaves. But keep the real purchase date, so you know when and where you bought.

An example with numbers

In October you pay: a fridge (installment 3 of 12, $120), sneakers (3 of 3, $31) and a phone (2 of 6, $49). This month you pay $200 in installments. The sneakers end: in November you pay $169. What stays committed after October: 9 × $120 + 4 × $49 = $1,276, until next July.

How Busimy does it

In Busimy you upload the card statement (PDF or photo) and AI reads each purchase with its installment. In Metrics → Installments you see what you pay this month, next month, which ones end, and a chart of how much is committed month by month until the last one. Each purchase keeps its purchase date and counts as spending of the month you pay the card.

What you really pay: the total cost

"Interest-free" installments can still cost something: fees, insurance or a list price higher than the cash price. What to look at is the total cost of credit (the APR plus every fee), which lenders are required to disclose in most countries.

Fixed installments and inflation: an example

With inflation, a fixed installment weighs a little less every month.
Month	Installment	With 3% monthly inflation, in today's money
1	$100	$97.10
3	$100	$91.50
6	$100	$83.70
12	$100	$70.10

How much of your income is already spoken for

The installment trap isn't one purchase, it's the total: five small ones together can take a big part of the next months' income. Before adding another, check what you pay in installments this month and until when.

Frequently asked questions

Are interest-free installments worth it?: With high inflation, often yes: you pay with money that is worth less. But know how much you already have committed before adding another.
What if I paid foreign-currency purchases with my own currency?: Record how much left your account and for how much of the foreign amount: that keeps the rate you really paid.