What a frequent flyer miles card does
A frequent flyer miles credit card earns you points toward airline tickets every time you use it to pay for something. You get miles for purchases at any merchant, plus bonus miles for spending in certain categories like dining or travel. When you have enough miles, you redeem them for a free or discounted flight with the airline that issued the card.
The card itself is a regular credit card — you get a bill each month and pay interest on any balance you carry. The miles are a reward layered on top. The airline doesn't pay you the miles; the card issuer (usually a bank) pays the airline to give them to you, and that cost gets built into the card's annual fee and the interest rates it charges.
Key Takeaways
- You earn miles on every purchase, but the card charges an annual fee (usually $95 to $450) whether you use the miles or not.
- A free flight from miles is only valuable if you would have bought that ticket anyway; the miles themselves have no cash value.
- The math works in your favor only if you spend enough to earn miles faster than you burn them, and you actually take the trips you book.
- Bonus miles offered when you open the card are the biggest source of value, but they come with a spending requirement you must hit within a set timeframe.
- Carrying a balance on the card to pay interest will erase any value from the miles you earn.
How the earning and redemption actually work
You earn miles at a fixed rate: typically 1 mile per dollar spent on most purchases, and 2 to 5 miles per dollar in bonus categories. A $100 grocery purchase might earn 2 miles if groceries are a bonus category, or 1 mile if they are not. These rates vary by card and change at the issuer's discretion.
To redeem, you log into your account and search for available flights. The price in miles varies wildly depending on the route, the airline's demand, and the time of year. A flight that costs 25,000 miles one week might cost 35,000 miles the next. You cannot see the cash price and the mile price side by side on most airline websites, so you have to do the math yourself: divide the dollar price by the miles required to see what each mile is worth to you on that specific flight.
If a flight costs $400 and requires 50,000 miles, each mile is worth less than a penny. If the same flight costs $600 and requires 50,000 miles, each mile is worth about 1.2 cents. That second scenario is when the miles are worth redeeming. On many routes and dates, the math does not work in your favor, and you are better off paying cash or using a different rewards card.
The annual fee and whether it pays for itself
Most frequent flyer miles cards charge an annual fee between $95 and $450. Some cards waive the fee for the first year. The fee is charged whether you use the card or earn any miles at all.
To break even on the fee, you need to earn miles worth more than the fee amount. A card with a $95 annual fee and a sign-up bonus of 50,000 miles is worth it only if those 50,000 miles can be redeemed for a flight worth at least $95 to you. On many airlines, 50,000 miles gets you a domestic round-trip flight in economy, which might be worth $300 to $600 depending on the route. That bonus alone covers the fee many times over — but only if you actually take that trip.
After the first year, you need ongoing spending to justify keeping the card. If you spend $5,000 per year and earn 1 mile per dollar, you earn 5,000 miles annually. At 1.2 cents per mile, that is $60 in value — not enough to cover a $95 fee. You would need to spend more, or the card needs to offer a higher earning rate or a valuable annual benefit (like a free checked bag or airline credit) that reduces the effective cost of the fee.
Sign-up bonuses and the spending requirement
The biggest reward on a frequent flyer miles card is the sign-up bonus: a large number of miles awarded when you open the account and meet a spending requirement. A typical offer is 50,000 miles after you spend $3,000 in the first three months.
The spending requirement is real and has a real important date. If you open the card on January 15 and the requirement is $3,000 in three months, you must charge $3,000 by April 15 or you forfeit the bonus. Some cards allow you to meet the requirement with a combination of your own spending and authorized user spending, but you cannot meet it with a balance transfer or cash advance.
The bonus is valuable only if you were going to spend that money anyway. If you spend $3,000 per month normally and you open a card requiring $3,000 in three months, you hit the requirement with money you would have spent regardless. If you normally spend $1,000 per month and you manufacture $3,000 in spending to hit the bonus, you are paying interest on money you did not need to borrow, which erases the value of the miles.
When the math works and when it does not
The frequent flyer miles card makes sense if all of these are true: you travel at least once or twice per year on the airline that issued the card, you spend enough to earn miles faster than you use them, you pay the full balance each month so you never pay interest, and you actually redeem the miles for flights you would have bought anyway.
The math breaks down if you travel rarely, if you accumulate miles but never redeem them, if you carry a balance and pay interest, or if you open multiple cards chasing bonuses and end up with annual fees on cards you do not use. A single month of interest charges on a $3,000 balance can erase the value of thousands of miles.
A simpler alternative is a flat-rate cash back card that gives you 2% back on all purchases. On $5,000 annual spending, that is $100 in cash back with no annual fee. You do not have to track redemption rates or plan trips around mile availability. The trade-off is that you will never get a $500 flight for free, but you also will never waste money on a card you do not use.
How to compare cards and avoid common traps
When comparing frequent flyer miles cards, write down three numbers: the annual fee, the sign-up bonus in miles, and the earning rate on your most common spending category. Then research what those miles are worth on the airline's website by looking up a flight you might actually take.
A common trap is chasing the largest sign-up bonus without checking whether you can meet the spending requirement without overspending. Another is opening multiple cards in a short time to stack bonuses, then getting hit with multiple annual fees and losing track of which cards you still need. A third is accumulating miles on an airline you do not fly often, then watching them expire (most airlines expire miles after three years of inactivity).
Before you open the card, ask yourself: Will I take at least one trip per year on this airline? Can I meet the spending requirement with money I was already planning to spend? Will I remember to use the card or will it sit in a drawer? If you answer no to any of these, the card is not worth the annual fee.
Frequently Asked Questions
Can I transfer miles between airlines or sell them?
Most airlines do not allow you to transfer miles to another airline, and you cannot sell miles for cash. Some airline partnerships allow transfers within a small group of partner airlines, but this is rare. Miles are locked to the airline that issued the card, which is another reason to choose a card for an airline you actually fly.
What happens to my miles if I close the card?
Your miles stay in your airline account and do not disappear when you close the credit card. However, if you do not earn or redeem any miles for three years, most airlines will expire them. Closing the card does not trigger expiration, but it does mean you stop earning miles on new purchases.
Do I have to pay taxes on the miles I earn?
The IRS does not tax miles you earn from credit card spending. However, if you receive a large sign-up bonus (typically over 25,000 miles), the card issuer may send you a tax form. Consult a tax professional about your specific situation, as rules vary.
Is it better to use miles for flights or to save them for upgrades?
Upgrades usually offer worse value than booking a full flight with miles. A $200 upgrade might cost 25,000 miles, while a $300 economy flight costs 50,000 miles. The upgrade is worth 0.8 cents per mile, while the flight is worth 0.6 cents per mile — both are low. Book the flight with miles only if the redemption value is at least 1 cent per mile or higher.
Can I use miles to book flights for other people?
Yes, most airlines allow you to book flights for family members or friends using your miles, as long as you provide their name and contact information. You cannot transfer the miles themselves to another person, but you can use your miles to purchase a ticket in their name.