Tools

Balance Transfer New-Purchase Interest Calculator

Carrying a 0% balance transfer usually kills the grace period, so every new purchase on that card accrues interest from day one. Estimate what that habit costs.

Purchase APR (%)

New purchases per month ($)

Months left on the 0% promo

Results (estimate)

Purchases parked on the card by promo end: $0
Interest those purchases accrue: $0
Same purchases on a separate grace-period card: $0

Model: payments cover the 0% balance first (how issuers apply the minimum), so purchases stack and accrue at the purchase APR until the promo ends. Real statements vary; treat this as the order of magnitude, not the penny.

How to avoid this entirely

The fix is the two-card strategy: the balance-transfer card carries the debt and nothing else, while a separate card with an intact grace period takes your daily spending at zero interest. The mechanics, the payment-allocation rules behind them, and what to do if you are already in the trap are in our balance transfer interest guide, with the underlying rules in how grace periods really work.