What air miles on a credit card actually are
Air miles are points you earn by spending money on a credit card, and you can redeem them for flights, seat upgrades, or sometimes hotel stays and other travel purchases. You don't earn them by flying — you earn them by charging purchases to the card. The airline or credit card company that issues the card decides how many miles you get per dollar spent, what those miles can be used for, and whether they expire.
The card issuer makes money when merchants pay a fee for each transaction you make. They give you miles as a reason to use their card instead of a competitor's. This is why the card usually charges an annual fee — sometimes $95 to $450 — even though you're earning rewards. The airline or card company is betting that the miles they give you are worth less than what they collect from merchants and from your annual fee.
Miles are not the same as cash back. You cannot convert them to dollars and deposit them in your bank account. You can only use them for what the program allows. If you never redeem them, they have no value to you, though some programs let you transfer miles to a travel partner or donate them to charity.
Key Takeaways
- Air miles are earned by charging purchases to a co-branded credit card, not by flying, and you redeem them only for travel or travel-related purchases the card program allows.
- The real value of a mile varies widely — sometimes 0.5 cents per mile, sometimes 2 cents or more — depending on which flight you book and which program you use.
- Annual fees on air miles cards often cost $95 to $450, so you need to redeem enough miles each year to cover that fee or the card costs you money.
- Miles expire if you don't use them within a set period, usually three to five years, though some programs reset the clock if you earn or redeem any miles.
- The best redemptions are usually off-peak flights on routes with high cash prices, because the miles cost stays the same whether the flight costs $200 or $800.
How many miles you earn and what they cost to redeem
Most air miles cards earn between 1 and 5 miles per dollar spent on purchases. Some cards earn more miles on specific categories — for example, 5 miles per dollar at restaurants and gas stations, 1 mile per dollar on everything else. A few premium cards earn 2 to 3 miles per dollar on all purchases, but these usually charge higher annual fees.
The cost to redeem a flight in miles is not fixed. Most programs use a dynamic pricing model, meaning the same flight might cost 25,000 miles on a Tuesday in February or 50,000 miles on a Friday in July. Some programs still use fixed award charts, where a flight from New York to Los Angeles always costs the same number of miles regardless of demand or season. Fixed charts are becoming rare, and when they exist, they're usually only for basic economy seats.
To figure out whether a miles redemption is worth it, divide the cash price of the flight by the number of miles required. If a flight costs $300 cash and 30,000 miles, each mile is worth 1 cent. If the same flight costs $600 and 30,000 miles, each mile is worth 2 cents. Most people find a redemption worthwhile when each mile is worth at least 1.5 cents, though premium cabin redemptions (business or first class) can be worth 3 to 5 cents per mile because those seats cost so much in cash.
Annual fees and whether they pay for themselves
Most air miles cards charge an annual fee between $95 and $450. Some cards waive the first year's fee, and a few waive it permanently if you meet spending thresholds. Before you open the card, calculate whether you'll redeem enough miles to justify the fee.
If your card charges $95 per year and you earn 2 miles per dollar on $10,000 in annual spending, you'll have 20,000 miles. If those miles are worth 1.5 cents each, they're worth $300 in redemption value — enough to cover the fee and come out ahead. But if you only spend $3,000 per year, you'll earn 6,000 miles worth about $90, which doesn't cover the fee. In that case, a no-annual-fee cash back card would save you money.
Some cards offer a statement credit or bonus miles to offset the annual fee. Read the cardholder agreement to see what you actually get. A $95 annual fee with a $100 statement credit is effectively free, but only if you use the credit. A $95 fee with 10,000 bonus miles is worth it only if you value those miles at more than $0.95 per mile, which is optimistic.
Expiration and how to keep miles from disappearing
Most airline miles programs expire if you don't earn or redeem any miles within three to five years. Some programs reset the expiration clock every time you earn or redeem miles, even a small amount. Others have a hard expiration date that doesn't move.
If your program resets on activity, you can keep miles alive indefinitely by redeeming a small amount — sometimes as little as 500 miles for a gift card or a donation — every few years. If your program has a hard expiration, you need to plan your redemption before that date or lose the miles.
Check your program's rules before opening the card. Some programs let you extend expiration by paying a fee, usually $25 to $50. This only makes sense if your miles are worth more than the fee — for example, if you have 50,000 miles worth $750 and the extension costs $25.
Sign-up bonuses and how to evaluate them
Most air miles cards offer a sign-up bonus: for example, 50,000 miles if you spend $3,000 in the first three months. This bonus is usually the biggest chunk of miles you'll earn in the first year, so it matters whether the bonus is worth the spending requirement.
To evaluate a bonus, multiply the miles by the value you expect per mile. If the bonus is 50,000 miles and you expect each mile to be worth 1.5 cents, the bonus is worth $750. If the card charges a $95 annual fee and you'll spend $3,000 anyway, you're getting $750 in value for $95 in fees — a good deal. But if you have to spend $3,000 extra just to hit the bonus, and you'd normally put that on a 2% cash back card, you're trading $60 in cash back for $750 in miles that might be worth only $750 or less in practice.
Be honest about whether you'll actually redeem the miles. If you have a history of letting points expire or never booking award flights, a sign-up bonus is just a reason to pay an annual fee for a card you won't use.
Comparing air miles cards to cash back and other rewards
An air miles card makes sense if you fly regularly and you're willing to plan redemptions around when award availability is good. It does not make sense if you fly once every few years, because you'll pay annual fees without earning enough miles to redeem.
A 2% cash back card with no annual fee will almost always beat an air miles card for someone who doesn't fly much. If you spend $10,000 per year, you'll earn $200 in cash back with no fee. An air miles card earning 2 miles per dollar would give you 20,000 miles, which you'd have to value at more than 1 cent each just to break even after the annual fee. That's possible, but it requires discipline about when and how you redeem.
Some people use both: a cash back card for everyday spending and an air miles card for specific categories or when they're planning a trip. This works if you're organized enough to track which card to use when. If you're not, stick with one card and one rewards type.
Common mistakes that cost you miles
The biggest mistake is redeeming miles for flights that are cheap in cash. If a flight costs $150 and requires 15,000 miles, you're valuing each mile at 1 cent — below what most people should accept. Wait for a flight that costs $400 or more, where the same 15,000 miles is worth 2.7 cents or more.
The second mistake is not checking seat availability before you commit to a card. Some programs have very few award seats on popular routes, especially during peak travel times. If you want to fly New York to Los Angeles in July, check the program's website first to see how many award seats are available. If there are none, the miles are worthless to you.
The third mistake is letting miles expire. Set a phone reminder for six months before expiration if your program has a hard important date. If you have miles you're unlikely to use, donate them to a charity or transfer them to a family member rather than watch them disappear.
Frequently Asked Questions
Can I transfer my miles to someone else?
Some programs allow transfers to family members or friends, usually for a fee of $15 to $50 per transfer. Others don't allow transfers at all. Check your program's rules. If you're not going to use the miles and transfers aren't allowed, some programs let you donate them to charity instead.
What happens to my miles if I close the credit card?
Closing the card does not automatically cancel your miles. Your miles stay in the airline program as long as you have account activity within the expiration window. You can keep redeeming them even after you close the card, as long as you don't let them expire.
Are airline miles taxable income?
Sign-up bonuses and miles earned from spending are generally not taxable as income. If you redeem miles for a flight and the airline sends you a 1099 form, consult a tax professional. Taxable situations are rare but do happen with certain redemptions or transfers.
Can I use miles from one airline on another airline's flights?
Not directly. Each airline's program is separate. Some airlines are part of alliances — for example, Star Alliance or OneWorld — and you can sometimes use miles on partner airlines within the same alliance, but the rules vary. Check your program's website to see which airlines accept your miles.
What's the difference between airline miles and credit card miles?
Airline miles are earned by flying and staying at partner hotels. Credit card miles are earned by spending on the card. Both usually go into the same airline account, and you redeem them the same way. The credit card is just another way to earn miles without flying.