Five best-buy 0% balance transfer deals have been cut this week, with the longest card now offering up to 36 months at 0%, and the longest no-fee card 28 months. If you've credit card debt to shift, act now before deals worsen.

Barclaycard today became the latest provider to cut a top deal – it's reduced the 0% period on its balance transfer card from up to 36 months to up to 35 months, while the fee's fallen from 1.85% to 1.35%.

That means the longest available balance transfer is now from MBNA, which offers up to 36 months 0% for a 2.49% fee. But that card was cut from 37 months on Wednesday, while the 0% length of its sister brand Nuba's card was shortened from 37 to 36 months the same day, with its fee worsening to 2.5%.

Meanwhile Sainsbury's Bank pulled its 36-month 0% card entirely on Monday and on Wednesday Halifax reduced the length of its no-fee 0% card from 29 to 26 months.

While all of the top deals are still long historically, they pale in comparison to a year ago, when the longest 0% length offered was a massive 43 months.

For a full rundown of how balance transfers work and all our current top picks, see our Balance Transfers guide.

What is a balance transfer?

A balance transfer is where you get a new card that pays off existing debt on other credit and store cards, so you owe it instead, but at 0%. This means more of your repayments go to reducing the debt, rather than paying interest, so you clear it quicker.

Most balance transfer cards will charge a small fee when you make the transfer, so always go for the card with the lowest fee within the time period – eg, 36 months – that you know you can pay it back in. If in doubt, go long, even with a bigger fee.

For most with ongoing debt the challenge is being accepted, so use our Balance Transfer 0% Eligibility Calculator which shows which 0% deal you're most likely to get before you apply, without affecting your creditworthiness.

Which cards now offer the longest deals?

MBNA now offers the longest 0% – up to 36 months for a 2.49% fee. Barclaycard has slipped to second place – up to 35 months for a 1.35% fee. Barclaycard's cheaper fee means it may be a better deal for those who don't need the extra month though.

We say 'up to' as some poorer credit scorers may be offered shorter 0% deals, though both of the cards above offer pre-approval – meaning if you use our Balance Transfer Eligibility Calculator you can see if you'll definitely get the full 0% period if accepted.

Alternatively, a Virgin Money card offers the same 35 months at 0% as the Barclaycard – it has a higher 2.8% fee, but it's not an 'up to' so everyone who gets accepted will definitely get the full 35 months at 0%.

The top no-fee 0% deal has also been cut

As above, on Wednesday Halifax reduced the length of its no-fee 0% card from 29 to 26 months. The best no-fee deal is now from Sainsbury's Bank, at 28 months 0%, followed by Santander offering one month fewer.

For more info on these see our No-fee 0% card best buys.