NEW YORK — The rules your credit card company operates by will start getting much clearer today.

Regulations aimed at reining in practices like unexpected interest rate increases and credit limit cuts start with two rules: Consumers will be given advance warning of any major changes to the terms of their accounts, and will get more time to pay their balance after receiving a bill.

These small changes come ahead of more sweeping regulations that will take effect in February. Those touch on matters ranging from mandating reviews every six months of accounts that have had rate hikes to limiting the credit that can be offered to students.

Card companies have been gearing up for the new landscape for months, mailing consumers a spate of warnings about fee and interest rate changes.

Starting today, card issuers must give consumers at least 45 days notice of a pending rate increase.

"That gives consumers a little time to shop around for another card," according to Eleni Constantine of the Pew Safe Credit Cards Project. "Should consumers choose to move to another card or just to close their current account, they can choose to reject the rate increase and effectively convert any existing balance to a closed-end loan that they can pay off at the current rate for up to five years."

Until now, card issuers have been able to charge higher rates — even on closed accounts — until a balance was paid in full.

Also beginning today, credit card issuers will be required to mail their bills at least three weeks before the payment is due. The previous requirement was 14 days.

Pew also found that the lowest introductory rates advertised by card issuers have increased. In July, the median rate was 8.75 percent, up from 5.99 percent in December, according to Pew.

If the notices already sent are any indication, consumers may not be happy about much of the new information they receive. Citi, for example, is in the process of informing some cardholders that it will institute an annual fee, about $30, on certain accounts.

Citi spokesman Samuel Wang said in an e-mailed statement that the new annual fees "also reflect the dramatically higher cost of doing business in our industry."

American Express Co. recently sent out notice it will eliminate over-the-limit fees on its consumer credit cards in October. They were dropped in response to a provision in that law that, starting in February, requires card companies to offer a way for customers to approve each transaction that triggers such a fee.

But the good news from Amex stopped there.

The letter Cynthia Vancho of New Jersey received last week from Amex informing her of the fee elimination also included notice that the interest rate on her card will jump to 10.24 percent from 6.99 percent. If she makes any late payments, the rate will shoot up to 27.24 percent.

And while overlimit fees are gone, Amex changed its fees for late payments to $19 for balances under $250, and $39 for balances above that line. The prior fees were $19 for balances under $400, and $38 for balances over $400.

Vancho sees rate and fee increases as penalizing good customers who did nothing wrong.

"They're taking advantage of the situation," she said. "I find it unfair for people who pay on time, pay over what is expected of them monthly and are basically good clients."

Amex spokeswoman Desiree Fish acknowledged that the regulations played a part in recent rate and fee hikes. "The reason why we did it is to be responsive to the business and economic environment, which obviously included the recent regulatory changes," she said.

The company started changing rates and fees in November. Rates on certain credit cards, including its Blue and Optima cards, have risen on average 4 percent, while co-branded cards such as airline miles cards are up an average of 2 percent.

"It's just part of the plan changes over the past few months that we've been making," Fish said.

CLEARER BILLING

A Pew survey of nearly 400 credit cards offered by the 12 largest issuers in the country found that rates have gone up an average of 2 percent since December. Banks are making the moves in response to an array of factors, including the regulatory changes and a spike in the number of accounts that have slipped into default as the unemployment rate has risen, said Nick Bourke, Pew project manager.

"They're trying to manage a lot of uncertainty, because they don't know what this market is going to look like once this law takes effect," Bourke said. "And they're trying to preserve a very profitable business."

The aim of all the new rules is to make credit card contracts easier for consumers to understand. The disclosures on most credit card contracts are "not comprehensible to the average consumer," said Gene Truono, managing director of BDO Consulting, who previously worked for both Chase cards and American Express.

In that sense, things like the requirement coming in February that banks spell out on a statement how long it will take to pay off a card balance making only the minimum payment, and how much interest that will cost, are bound to help consumers manage their credit better, Truono said.

"It passes what I call the 'Dolores test,' " he said, explaining that Dolores is his octogenarian mother. "If most consumers read them and can actually understand them, it really does have the intended effect."

Nevertheless, while the new regulations will curtail many of the practices the credit card industry has been criticized for in recent years, Truono said consumers must still stay on top of their accounts.

"The disclosures are only as good as the consumers who actually read them," he said.