Miles are a currency your card issuer creates, and you earn them by spending
Credit card miles are points that card issuers award based on how much you charge. The issuer — usually a bank or the card network itself — creates the miles program and sets the earning rate. Most cards earn 1 mile per dollar spent, though some earn 2, 3, or even 5 miles per dollar on certain categories like flights or restaurants.
You do not buy miles with cash. You earn them automatically when you use the card. If your card earns 2 miles per dollar and you spend $500 at a grocery store, you receive 1,000 miles in your account. Those miles sit in an account managed by the card issuer until you decide what to do with them.
The miles themselves have no inherent value. A mile is worth whatever the issuer decides it is worth on any given day. This matters because the redemption value can shift, and a mile you earned last year might be worth less when you try to use it.
Key Takeaways
- You earn miles automatically when you use the card, at a rate set by the issuer — typically 1 to 5 miles per dollar spent depending on the category.
- Miles can be redeemed for flights through the card's travel portal or partner airlines, but the price in miles changes based on demand and availability.
- The real value of a mile depends on what you redeem it for — a mile used for a $500 flight is worth roughly half a cent, while a mile used for a $100 flight is worth about one cent.
- Miles expire if your account is closed or inactive for a set period, usually 12 to 24 months, so you need to use them or keep the card active.
- Partner transfers and airline redemptions often offer better value than redeeming through the card's own portal, but require more planning.
How redemption works: the travel portal versus partner airlines
Most cards let you redeem miles in two ways. The first is through the card issuer's own travel portal — a website where you search for flights, hotels, and rental cars, then pay in miles instead of dollars. You see the mile price before you book. A flight might cost 25,000 miles, a hotel night 10,000 miles. The portal is straightforward but usually the worst value.
The second way is partner transfers. The card issuer has relationships with specific airlines and hotel chains. You transfer your miles from your card account directly to an airline's frequent flyer program, then book through that airline using their own award chart. This is where the real value often lives, because airline award charts price flights differently than the card's portal does.
An example: a flight that costs 50,000 miles on the card's portal might cost 30,000 miles when you transfer to the airline and book directly. You get the same flight for 20,000 fewer miles. The catch is that you have to know which airlines offer good value, and you have to move your miles before you book — you cannot transfer them back if you change your mind.
Why the same flight costs different amounts in miles
The card's travel portal uses a dynamic pricing model. The issuer buys blocks of flights from airlines at wholesale rates, then marks them up and sells them to you in miles. The markup changes based on demand. A popular route on a Friday night costs more miles than the same route on a Tuesday morning, just like it would cost more dollars.
Airline award charts work differently. Most major airlines use dynamic pricing too, but the price bands are wider and change less frequently. A flight in economy might always cost between 25,000 and 50,000 miles depending on the season, whereas the portal might price the exact same seat at 35,000 miles one day and 55,000 miles the next.
This is why transferring to a partner airline can save you miles on the same flight. You are not paying the card issuer's markup. You are paying the airline's own award price, which is often lower for off-peak travel and higher for peak travel, but with less day-to-day fluctuation.
What a mile is actually worth
The value of a mile depends entirely on what you redeem it for. If you use 50,000 miles to book a $500 flight, each mile is worth about one cent. If you use 50,000 miles to book a $250 flight, each mile is worth half a cent. The same miles in the same account have different values depending on the redemption.
This is why comparing cards by "miles per dollar earned" alone is misleading. A card that earns 5 miles per dollar is not automatically better than one that earns 2 miles per dollar if the 5-mile card's miles are worth less when you redeem them. You have to think about both the earning rate and the redemption value.
Most people find that miles are worth between 0.5 cents and 1.5 cents each when redeemed for flights through partner airlines. Portal redemptions often value miles lower, around 0.5 to 1 cent. If you redeem for non-travel rewards — gift cards, merchandise, cash back — the value is usually even lower, sometimes as little as 0.3 cents per mile.
How miles expire and what keeps them alive
Miles do not expire as long as your account is active. Most issuers define "active" as any account activity — a purchase, a transfer, a redemption — within the past 12 to 24 months. If your card sits unused for longer than that, the issuer can close the account and forfeit your miles.
The easiest way to keep miles alive is to use the card occasionally. Even a small purchase every year or two keeps the account open. Some issuers also let you keep miles alive by logging into your account or transferring miles to a partner program, though the rules vary by issuer.
If you have a large balance of miles you are not ready to use, check your card's specific policy. Some cards have no expiration as long as the account is open. Others require activity. A few allow you to "refresh" your miles by making a small purchase or paying a fee. Knowing the rule for your card prevents you from losing miles you have already earned.
Earning miles faster: bonus categories and sign-up offers
Most travel cards earn extra miles in specific categories. A card might earn 3 miles per dollar on flights and 1 mile per dollar on everything else. Another might earn 2 miles per dollar on restaurants and 1 mile per dollar elsewhere. The category bonuses are where you accumulate miles fastest if you spend heavily in those categories.
Sign-up bonuses are the other major source. A new card might offer 50,000 bonus miles after you spend $3,000 in the first three months. That 50,000 miles is awarded once, when you meet the spending requirement. It is not recurring. But it can represent months or years of regular earning, which is why sign-up bonuses are often the best way to build a large balance quickly.
Some cards also offer periodic bonus categories that change each quarter — for example, 4 miles per dollar on groceries for three months, then 4 miles per dollar on gas for the next three months. These are temporary and rotate, so you have to track them to take full advantage.
Common mistakes that waste miles
The biggest mistake is redeeming through the card's portal when a partner airline offers better value. Many people do not realize the option exists or do not know which partners offer good rates. Spending 10 minutes comparing the portal price to a partner airline's award chart can save you thousands of miles on a single booking.
The second mistake is letting miles expire. This happens most often when someone earns a large balance, stops using the card, and forgets to check the expiration policy. The miles vanish because the account went inactive. Setting a phone reminder to use the card once a year, or to check the balance, prevents this.
A third mistake is redeeming miles for low-value rewards like gift cards or merchandise. A $100 gift card that costs 50,000 miles values each mile at 0.2 cents — far below what you could get by redeeming for a flight. If you are not going to use miles for travel, cash back or a statement credit is usually a better option.
Frequently Asked Questions
Can I transfer miles between different credit cards?
No. Miles earned on one card stay in that card's account and cannot be moved to another card. You can transfer miles to partner airlines or hotels, but not between card accounts. If you close a card, you lose the miles in that account unless you transfer them to a partner first.
What happens to my miles if I close the card?
Most issuers close the miles account and forfeit the balance when you close the card. Some allow a grace period — usually 30 to 90 days — to transfer miles to a partner before they are lost. Check your card's terms before closing an account with a large balance.
Are miles taxable income?
Miles earned through normal spending are not taxable. Miles earned through a sign-up bonus or promotional offer are also not taxable in most cases. However, if you receive miles as compensation for work or services, they may be taxable. Consult a tax professional if you are unsure about your specific situation.
Can I buy miles directly from the card issuer?
Yes, most issuers let you purchase miles directly, though the price is high — usually 1 to 2 cents per mile. Buying miles is rarely worth it unless you are very close to a redemption you want and do not want to wait to earn more. Some issuers also offer discounted miles during promotional periods.
Do I have to use miles for flights, or can I redeem them for other things?
Most cards let you redeem miles for flights, hotels, rental cars, and other travel purchases through the portal. Many also allow cash back, statement credits, or merchandise redemptions. The value is usually lowest for non-travel redemptions, so travel is typically the best use of miles.