0% APR Ticking Time Bomb
0% APR Promo Payoff Calculator
What this calculator does
This calculator compares your payment plan against the promo deadline. It warns you if the balance will not be paid off before the regular APR kicks in.
The math, with a worked example
Months until promo end = promo end date − today. Months to pay off = balance ÷ monthly payment. If the payoff months exceed the promo months, the remaining balance is hit with the post-promo APR. A $1,500 balance with a $200 monthly payment pays off in 7.5 months. If the promo ends in 6 months, you will owe a small balance when deferred interest may apply.
Why this matters
0% promos are interest-free only on a deadline: pay off in time and it was free money; miss by a month and the post-promo APR lands on what's left. $200 a month against $1,500 takes 7.5 months — a 6-month promo turns that tail into real interest.
Methodology and transparency
Months to pay off = balance ÷ monthly payment, compared against months left in the promo; any shortfall accrues at the post-promo APR. The dangerous fine print the model flags but can't read for you: deferred-interest promos (common in store financing) charge back interest on the entire original balance if any amount survives the deadline, not just the remainder. Everything runs in your browser; no data is sent or stored.
Last reviewed: 2026-08-08
Common questions
What is deferred interest?
If you do not pay the full balance before the promo ends, the card may retroactively charge interest on the original balance.
How do I avoid the ticking time bomb?
Divide the balance by the number of months left in the promo and pay that amount every month.
What happens after the promo?
The remaining balance starts accruing interest at the post-promo APR, usually a high rate.