The Finance Algorithm

Interest-Free Period Calculator

How many interest-free days you really get, and how to time purchases

Updated October 2026Built and checked by MaverickHow it's calculatedReport an error

Your numbers

Updates as you type
15

Day your statement closes (1-28)

21

Usually 21-25 days after statement

16

When you make the purchase

$
$1k
%
21.24%

For comparison if you miss payment

The button asks our AI to explain these figures in words.

Interest-free period

Interest-free days

50 days

from purchase to due date

Best possible

50 days

day after statement (16)

Worst possible

21 days

day of statement (15)

Missed payment cost

$18

first month interest on $1,000

Worst vs your purchase vs best

You've timed your purchase well: you're at the maximum interest-free period.

21 daysWorst (statement day)50 daysYour purchase50 daysBest (day after)

Interest-free days for each purchase day

Just after statement close = longest period. Just before = shortest. Schedule big purchases accordingly.

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Interest-free only if paid in full. One missed full-balance payment and you lose the interest-free period, and interest typically backdates to the purchase date. Set up auto-pay for the full statement balance to never lose this valuable feature.

How it works

Interest-free days only count if you pay the full closing balance each month, and the advertised number, often 44 or 55 days, is the most you get. A purchase made near the end of a statement period gets far fewer. This works out how many days you'd really have.

  1. 1Enter your statement closing date
  2. 2Add the days until your due date
  3. 3Enter the day of the month you'd make the purchase
  4. 4See your interest-free days for that purchase
  5. 5Learn optimal timing for big purchases

The figures today

As of 7 November 2026, the lowest credit card purchase rate is 7.49%, from Unity Bank's Low Rate Visa Credit Card, while the typical best across 51 institutions is 12.49%.

Worked examples

Buying Just After the Statement

The statement closes on the 15th and payment is due 21 days later. A $1,000 purchase on the 16th.

Statement closing day of month
15
Days until due date (after statement)
21
Purchase day of month
16
Purchase amount
$1,000
Card interest rate
20%

Bought the day after the statement closes, it lands on the next statement and has 50 days before payment is due - the most this card gives.

Buying Just Before the Statement

The same card, with the $1,000 purchase on the 14th.

Statement closing day of month
15
Days until due date (after statement)
21
Purchase day of month
14
Purchase amount
$1,000
Card interest rate
20%

Bought the day before the statement closes, it has only 22 days, 28 fewer. Either way there's no interest if the whole statement balance is paid by the due date.

Questions people ask

Do I get interest-free days on cash advances?
No. Cash advances start accruing interest immediately from the date of the transaction. There's no interest-free period for cash or cash-equivalent transactions.
What happens if I only pay part of my balance?
You lose the interest-free period completely. Interest is charged from the purchase date on the unpaid amount, and new purchases start accruing interest immediately.
Can I change my statement closing date?
Some lenders let you change your statement or due date - ask yours. Choosing a date just after payday makes it easier to pay in full.

The terms, in plain English

Interest-Free Period
Time between purchase and due date when no interest is charged if paid in full.
Statement Closing Date
When your monthly statement is generated - purchases after this go on next statement.
Due Date
Deadline to pay your statement balance to avoid interest and late fees.

Official sources