Miles are a currency you earn by spending on a credit card, then redeem for flights or other travel purchases at a rate that varies by card and airline
When you use a credit card that earns miles, the card issuer credits your account with a certain number of miles for each dollar you spend. The most common earning rate is one mile per dollar, though some cards earn two or three miles per dollar on certain categories like dining or travel. These miles sit in an account tied to your card until you decide to use them.
The value of those miles depends entirely on what you redeem them for. A mile might be worth 0.5 cents or 2 cents, depending on whether you're booking a domestic flight or an international one, whether you're flying during peak season, and which airline's award chart you're using. This is why two people with the same number of miles can get very different value from them.
Key Takeaways
- Miles are earned at a fixed rate (usually one per dollar spent) but redeemed at a variable rate that depends on the flight, airline, and how far in advance you book.
- You can redeem miles directly through the card issuer's website or through the airline's website if your card is co-branded with that airline.
- Peak travel dates cost significantly more miles than off-peak dates on the same route, sometimes double or more.
- Miles expire if your account is inactive for a set period (typically 12 to 24 months), so tracking your balance and using them periodically matters.
- The real value of miles depends on how you use them — booking expensive flights in premium cabins yields higher cents-per-mile value than booking cheap economy flights.
How earning rates work and what they mean for your spending
Every credit card that earns miles specifies its earning rate in the terms. The simplest cards earn one mile per dollar on all purchases. Others earn different rates depending on the category: a card might earn three miles per dollar on dining, two miles per dollar on travel, and one mile per dollar on everything else.
To calculate how many miles you'll accumulate, multiply your annual spending in each category by the earning rate. If you spend $10,000 per year on dining with a card that earns three miles per dollar on dining, you'll earn 30,000 miles from that category alone. Over two years, that's 60,000 miles — enough for a domestic round-trip flight on many airlines.
The earning rate is fixed and may provide. What changes is the redemption rate, which is why a card that earns one mile per dollar on everything might deliver better value than a card that earns three miles per dollar on a narrow category you don't spend much in.
Redemption: how to turn miles into flights
Once you have miles in your account, you can redeem them through two main routes. The first is the card issuer's travel portal — a website where you search for flights, hotels, and rental cars, then pay with miles instead of cash. The second is the airline's own award chart, which you access if your card is co-branded with that airline (like a United card or an American card).
The travel portal approach is simpler for beginners because you see the price in miles upfront and book like you would with cash. The downside is that the portal often prices flights at a worse rate than the airline's own award chart. A flight that costs 25,000 miles on the airline's website might cost 30,000 miles through the card issuer's portal.
The airline award chart requires more research but often delivers better value. You search for the flight on the airline's website, find the award price in miles, and then book it. Award prices are fixed by route and season, not by demand the way cash prices are. A flight from New York to Los Angeles might always cost 25,000 miles in economy during off-peak season, regardless of whether the cash price is $150 or $400.
Peak and off-peak pricing: why the same flight costs different miles on different dates
Airlines divide the year into peak, standard, and off-peak travel periods. Peak periods include summer vacation, winter holidays, and spring break. Off-peak periods are typically January through early March and September through November. The same flight can cost 50% more miles during peak season than during off-peak season.
For example, a round-trip flight from Chicago to Miami might cost 25,000 miles per person in January but 40,000 miles per person in July. If you're flexible with your travel dates, shifting your trip by a few weeks can cut your mile cost significantly. This is one of the main ways experienced mile users get more value from their accounts than casual users.
Peak pricing applies to both the airline's award chart and the card issuer's travel portal, though the portal's peak prices are often higher. Checking both before you book is worth the five minutes it takes.
How many miles you need for different types of flights
Domestic round-trip flights in economy typically cost between 20,000 and 35,000 miles depending on the airline and season. A short flight (under 500 miles) might be 20,000 miles off-peak, while a cross-country flight might be 35,000 miles during peak season.
International economy flights start around 40,000 miles for short routes (like US to Canada) and climb to 60,000 to 80,000 miles for long-haul flights (like US to Europe or Asia). Business class is significantly more expensive: a domestic business class seat might cost 50,000 to 75,000 miles, while international business class can run 100,000 to 200,000 miles or more.
These numbers vary by airline and route. The only way to know the exact price for your specific flight is to search the airline's award chart or the card issuer's portal. Award charts are public and searchable on every major airline's website, so you can check prices before you commit to a card.
What happens to miles you don't use
Most credit card miles expire if your account is inactive for 12 to 24 months. "Inactive" typically means you haven't earned or redeemed any miles during that period. Some cards reset the clock if you make any purchase on the card, even if it doesn't earn miles. Others require you to actually earn miles to keep your account active.
The expiration policy is in your card's terms and conditions. If you're not planning to use your miles soon, check the policy before your account goes dormant. A straightforward way to keep miles active is to use the card for a small purchase every year or so, or to redeem a small amount of miles (even if it's just a $5 gift card through the portal) to show account activity.
If your miles do expire, you may be able to reinstate them by calling the card issuer and asking. Some issuers will restore expired miles once if you ask, though this is not may provide and depends on the card and the issuer's policy.
Comparing the real value: cents per mile
To compare whether one card's earning rate is better than another's, convert miles to their cash value. Divide the cash price of a flight by the number of miles required to book it. If a flight costs $300 cash and 25,000 miles, each mile is worth 1.2 cents ($300 ÷ 25,000 = $0.012).
Most miles are worth between 0.5 and 2 cents each when redeemed for flights. Premium cabin bookings and long-haul international flights tend to deliver higher value (1.5 to 2 cents per mile), while short domestic flights and economy bookings often deliver lower value (0.5 to 1 cent per mile). If you mostly book short flights in economy, your miles won't stretch as far as someone who books international business class.
This is why the best card for you depends on your actual travel patterns, not just the earning rate. A card that earns three miles per dollar is only valuable if you can redeem those miles at a rate that makes the earning worthwhile.
Frequently Asked Questions
Can I transfer miles between credit cards or to someone else?
Miles are tied to your account with the card issuer or airline, not to the physical card itself. You cannot transfer miles to another person's account. You can sometimes transfer miles between your own accounts if you have multiple cards from the same issuer, but this varies by card and issuer. Check your card's terms or call the issuer to confirm.
What if I want to book a flight but don't have enough miles?
Most airlines allow you to "top up" your miles account by purchasing additional miles directly from the airline. The cost is usually high — you might pay $0.01 to $0.02 per mile — so this is rarely worth it unless you're very close to your redemption goal. A better option is to earn more miles by using your card for regular spending, or to book a cheaper flight that requires fewer miles.
Do miles have the same value on every airline?
No. The same number of miles buys different flights on different airlines. One airline might charge 25,000 miles for a flight that another airline charges 30,000 miles for. This is why comparing award charts before you choose a card matters. Some cards are co-branded with a specific airline, which can lock you into that airline's pricing.
What's the difference between airline miles and credit card points?
Credit card miles are a specific type of point that are usually tied to a particular airline or airline alliance. Some credit cards earn "points" instead, which can be redeemed for flights, cash, or other rewards through the card issuer's portal. Points are often more flexible but may be worth less per unit than miles. Check what your card earns before you sign up.
Can I use miles to book flights for other people?
Yes, but the person flying must be listed on your account or be a family member, depending on the airline's rules. You cannot use your miles to book a flight for a stranger. Most airlines allow you to book for a spouse, child, or parent. Check the specific airline's policy before you attempt to book.