Cardhub.com found that the finance free windows now on average last 10 months, up from seven last year with many lasting as long as 18 months.
Taking advantage of these offers can save a card holder hundreds of dollars on balance transfers.
But there are catches.
Experts say zero percent transfer offers are usually worth it if you carry a balance of more than $1,000. They warn to watch out for transfer fees, which average about 3 percent of the transferred amount. And if you add new purchases to the card, you should know that payments are applied to the highest-rate debt first, which could mean a longer time to pay off the transferred amount.