The Best Ways to Track 0% APR and Balance Transfer Deadlines

A 0% APR card is one of the best deals in personal finance, right up until the promo ends and you still have a balance. Then whatever's left starts getting charged the card's regular rate, which is usually one of the highest you have.

The tricky part isn't the math. It's remembering. Every promo has its own end date, it's rarely the same day as your due date, and if you have more than one, they're all on different timelines.

Full disclosure: I built one of the tools on this list, so I'm biased on that one. Here's what each option is actually good at.

At a Glance

First, Know Which Kind of 0% You Have

Not all 0% offers work the same way, and the difference can cost you a lot.

• A true 0% intro APR is what most bank credit cards offer. If you still have a balance when the promo ends, the regular rate applies to what's left from that point on.
• Deferred interest is common on store cards and "no interest if paid in full" financing. If you don't pay the whole balance by the deadline, you're charged interest going all the way back to the purchase date. The CFPB explains that this interest is usually calculated on the balance you owed in each month since the purchase.

If you have a deferred interest balance, the deadline matters even more. The good news: the front page of your statement has to show when the deferred interest period ends.

Cardinate (Built for Promo Deadlines)

This is mine. Cardinate only does credit cards, and 0% deadlines are one of the main reasons I built it. You add each card's promo balance and end date, and it shows how much time is left and how much you need to pay each month to clear it before the regular rate kicks in. It emails you before each promo ends, and it does the same for due dates and annual fees.

For example, say you moved $3,000 to a card with 0% for 15 months and paid a 3% transfer fee. That's $3,090 to clear, or about $206 a month. Cardinate shows that number next to the card, along with the gap between it and what you're paying now.

• Price: Free for unlimited cards you add by hand, including promo deadlines and reminders. Pro is $12.99 a month or $129 a year, with a 14-day free trial and no card needed. It adds a promo-first payoff plan that puts your soonest-ending promos first, plus bank sync through Plaid so balances update on their own.
• Good for: Anyone with more than one card, especially if one or more has a 0% promo.
• Not for: Loans or mortgages. It's credit cards only.

If that sounds like you, you can try Cardinate free, or start with the free 0% APR tracker.

Undebt.it (Payoff Plans With Promo Rates)

Undebt.it is a web-based debt payoff planner that's been around since 2012. Each debt has a promo interest section where you can set how long the promo rate lasts, and you can mark an account as deferred interest, which moves it to the top of your payoff plan.

A couple of limits are worth knowing. Undebt.it says it doesn't calculate the back interest on a deferred balance for you. And in the latest answer I could find in their help comments, multiple promo rates on one account were still listed as a future feature, so if one card has two promos, you may need to split it into two entries.

• Price: Free, with an optional Undebt.it+ upgrade for $10 a year that adds reminders, a home screen app and bank sync.
• Good for: People who want promo deadlines inside a detailed payoff plan for every kind of debt.
• Not for: A quick card-by-card view of deadlines, due dates and fees.

Your Card Issuer's App

Your bank's app or online account shows your promo details, and your statement lists the promo balance and rate. For deferred interest, the end date has to be on the front of the statement.

• Price: Free.
• Good for: Checking one card's promo when you remember to look.
• Not for: Seeing all your promos together. With promos at three banks, you're checking three apps, and the details aren't always easy to find.

A Calendar Reminder

The simplest option works better than nothing. Add an event on the day before your promo ends, with reminders 60 days and 30 days ahead. Put the balance you need to clear in the event so future you knows what to do.

• Price: Free.
• Good for: One or two promos.
• Not for: Tracking progress. A calendar tells you the date is coming, not whether you're on pace.

A Spreadsheet

A spreadsheet with each card, promo balance, end date, and the monthly payment needed (balance divided by months left) works if you'll update it.

• Price: Free.
• Good for: People who like full control.
• Not for: Reminders. A spreadsheet will never tell you a promo ends next week. I wrote more about when a spreadsheet stops working.

What About Budgeting Apps?

Budgeting apps like YNAB, Monarch and Copilot track your card balances, but they're built around spending, not promo deadlines. If you already use one, pair it with a calendar reminder or a dedicated tracker for your 0% end dates.

There are also a couple of apps built just for 0% deals, like ZeroBasis and OnRemind, but they're aimed at UK cards.

Tips That Work With Any Tool

• Divide and pay. Take the promo balance and divide it by the months left. That's your monthly target, and it's usually far more than the minimum.
• Aim to finish a month early. The promo end date often isn't your due date, so leave yourself some room.
• Avoid new purchases on a balance transfer card. Anything you pay above the minimum generally goes to the balance with the highest rate first, so extra payments can go to new purchases instead of the promo balance. On a deferred interest balance, that changes in the last two billing cycles, when extra payments must go to the deferred balance.
• Never pay late. Being more than 60 days late can cost you the promo rate and trigger a penalty rate.

So Which One Should You Use?

• You have one promo: a calendar reminder plus your bank's app is enough.
• You have several cards and at least one promo: that's exactly what Cardinate is built for.
• You want promos inside a payoff plan for every kind of debt: Undebt.it.
• You like doing it yourself: a spreadsheet, as long as you update it.

The Quick Version

• A true 0% promo charges the regular rate on what's left when it ends. Deferred interest charges interest back to the purchase date.
• Divide the promo balance by the months left to get your monthly target.
• Cardinate tracks every card's promo deadline with reminders, free for unlimited cards by hand.
• Undebt.it supports promo rates and deferred interest inside a payoff plan.
• A calendar reminder works fine for one or two promos.

If you're juggling more than one promo, Cardinate is free to start. Add your cards by hand, or connect your banks with the free Pro trial.

Prices were checked in November 2026 and can change, so confirm on each app's site.

Sources

• CFPB: How does a no interest if paid in full purchase work?
• CFPB: Regulation Z, periodic statement disclosures (12 CFR 1026.7)
• Experian: What happens when your 0% introductory APR ends
• Undebt.it: Dealing with deferred interest accounts and Undebt.it+ features and pricing
• ZeroBasis: zerobasis.app
• OnRemind: 0% credit card ending reminder