Getting credit card offers in the mail or online doesn’t guarantee that you’ll be approved for a card. To get a credit card in your name, you must meet a basic set of qualifications. Other requirements vary by card, and they’ll generally get tougher as you move into products with low-interest rates, hefty rewards, or special benefits.

If you’ve been rejected and don’t know why, or if you haven’t applied for plastic in a long time (or at all), here’s what you need to know about qualifying for credit cards.

You Must Be Old Enough

By law, you must at least 21 to open a credit card in your own name. However, most issuers do grant credit to people as young as 18 if they can show proof of income.

The application is more rigorous for younger borrowers, requiring them to submit pay stubs or bank statements to ensure they can repay debts. (So, no, your weekly babysitting gig probably won’t cut it.)

However, if you do earn a decent income, you can get started with credit cards all on your own. Some issuers also offer student credit cards with lower credit limits designed to ease younger consumers into using credit.

You Need Income

Credit issuers want to make sure you’ve got a steady paycheck before extending a line of credit to you, says Bob Harkson, chief financial planning officer at Phase 2 Wealth Advisors in Gig Harbor, Washington. That’s why one of the main set of questions on an application focus on your employment status and your earnings.

Unlike applicants in the 18- to 20-year-old group, though, income information on a credit application is self-reported, meaning the card issuer probably won’t check up on you. That said, lying can create problems, so just be honest.  Also, keep in mind that income includes money the applicant has “reasonable access” to, such as a spouse’s income. Other earnings count, too, like alimony, rent from tenants, government benefits, and retirement benefits.

If you’re a first timecard-owner, it may be a great idea to get a card with no annual fee, a low interest rate and 0% balance transfer rates. There are also great cash back rewards credit cards that offer great rewards and are some of the best credit cards out there.

You Need a Credit History (With Exceptions)

You might wonder how you can establish a credit history if no one gives you a credit.

Credit issuers do want to see you’ve been able to borrow and repay responsibly in the past. “There are some people who have paid cash all of their lives and haven’t shown they can pay a loan off, making it difficult to get approved for a card,” Harkson says.

In those situations, certain credit cards help new or previous credit users build credit. The options include secured credit cards, for which you typically must deposit cash in the amount of what your credit limit will be. After several months of responsible use and on-time payments a secured card, you usually can graduate to more mainstream, unsecured credit cards. Until you prove yourself, though, a nonexistent or thin credit file likely will put your application in the rejection pile.

Your Credit Should Be in Good Standing

To get an idea of where you stand before you apply for a card, check your credit report, Harkson recommends. You can get a free copy of your credit report once a year from each of the three major credit bureaus (Equifax, Experian and TransUnion) through annualcreditreport.com.

You also should check your credit score. You might be able to get your score for free through a bank, a financial app, or a personal finance website. If your score isn’t that great (the scale typically goes from a low of 300 to a high of 850) or recent late payments show up on your report, it might be challenging to get approved for a card with favorable terms, such as a low APR.

“If you pull your credit report and it looks like you don’t meet the credit score qualifications of a particular card, you’ll at least see which areas you need to work on,” Harkson says.

Regularly making on-time payments and keeping balances as close to zero as possible boosts your score over time. But if your credit history and score aren’t where you’d like them to be, you might need to settle for a card geared toward people with poor or average credit or look at a debit card.

You Can’t Be Drowning in Other Debt

In addition to income, a card issuer will ask about your debt, such as an auto loan or a mortgage.

“If your expenses are $2,000 a month and you report that you earn $2,500 in monthly income, there’s a good chance you won’t get a credit card,” Harkson says.

Another indication that you might have trouble paying your bills can be found within your credit report. Your report will show how much debt you’re carrying compared with your available credit (known as credit utilization). So, if you have $10,000 in available credit but owe $8,000, that means your utilization rate is 80%. The higher this number, the more of a risk you pose to a card issuer and are less likely to be able to open a credit card account.

Credit utilization is the second most important factor when calculating your credit score (right behind payment history).

Bottom Line

Most credit card issuers don’t keep their qualification criteria secret, although you might need to dig for the details. It’s worth your time, though, since it can give you a sense, before you fill out an application, of whether you’ll be approved for a new credit card. Even if your credit isn’t where you’d like it to be, as long as you meet the age requirements and earn ample income, you should be able to find a card that matches your situation and could even offer perks such as cash rewards, travel rewards, and 0% intro APR and first year bonuses.