Credit card miles can look complicated because banks often do not award airline miles directly. Instead, you usually earn bank rewards points or bank miles first, which can later be transferred to an airline loyalty programme such as KrisFlyer.
The basic idea is simple:
Spend on the right credit card → earn bank points or miles → transfer them to an airline programme → redeem them for flights or other rewards.
This guide explains the fundamentals before you start comparing individual miles cards.
Last updated: 9 September 2026. Credit-card earn rates, transfer fees, exclusions and promotions can change. Always check the latest bank terms before applying for or using a card.
What Are Credit Card Miles?
When people say that a credit card earns “miles”, they are usually referring to rewards that can eventually be converted into airline miles.
For example:
- Some cards award a bank’s own rewards points
- Some cards award a bank-specific “miles” currency
- Those rewards can then be transferred to participating airline loyalty programmes
A useful distinction is:
| Stage | Example |
|---|---|
| Credit-card reward currency | UOB UNI$, Citi Miles |
| Airline loyalty currency | KrisFlyer miles, Asia Miles |
| Final use | Flight redemptions, upgrades or other rewards |
The reward you earn from the bank and the airline mile you eventually redeem are therefore not always the same thing.
Bank Points vs Airline Miles
This distinction matters because bank rewards and airline miles may have different expiry rules.
For example, UOB UNI$ currently expire 2 years from the last day of the periodic quarter in which they were earned.
Citi PremierMiles, on the other hand, currently advertises that Citi Miles do not expire.
Once bank rewards are transferred into an airline programme, they become subject to that airline programme’s own rules.
For ordinary KrisFlyer members, KrisFlyer miles are generally valid for 3 years from the date they are earned.
Key idea: Keeping rewards with the bank for longer can sometimes preserve flexibility, but you must also watch the bank reward’s own expiry date.
How Do You Actually Earn Miles?
Miles cards usually fall into two broad groups.
1. General-Spend Cards
These earn a lower rate across a wider range of eligible spending.
For example, a card may earn:
1.2 miles per dollar (mpd)
on ordinary local retail spending.
The advantage is simplicity. You do not need to think as much about spending categories.
2. Bonus-Category Cards
These offer a much higher earn rate when you meet specific conditions.
A common example is:
4 miles per dollar (4 mpd)
on eligible online or mobile-contactless transactions.
The trade-off is that bonus cards often have:
- Monthly caps
- Eligible spending categories
- Merchant Category Code (MCC) exclusions
- Payment-method requirements
- Different treatment once the bonus cap is reached
This is why a good miles strategy often combines a high-earning specialist card with a general-spend fallback card.
What Does 4 Miles Per Dollar Actually Mean?
If a transaction earns 4 mpd:
$500 × 4 mpd = 2,000 miles
If the same $500 transaction earns 1.2 mpd:
$500 × 1.2 mpd = 600 miles
| Eligible Spend | 1.2 mpd | 4 mpd |
|---|---|---|
| $100 | 120 miles | 400 miles |
| $500 | 600 miles | 2,000 miles |
| $1,000 | 1,200 miles | 4,000 miles |
The difference becomes substantial over time.
For a deeper explanation of caps, MCCs and bonus categories, read Understanding Miles Per Dollar.
How Are Bank Rewards Converted?
Each bank has its own conversion system.
For example, UOB currently states that:
UNI$1 = 2 KrisFlyer miles or Asia Miles
for one-time frequent-flyer conversions, subject to the bank’s required conversion blocks.
UOB currently charges $27 per one-time conversion.
Citi currently charges $27.25 per Points Transfer from eligible Citi cards, including Citi Miles transfers, subject to its terms.
This is one reason you may not want to transfer very small amounts repeatedly.
Instead of paying a transfer fee every few weeks, it can be more efficient to accumulate a useful balance and transfer when you actually have a redemption plan.
Do Miles Have a Fixed Dollar Value?
No.
A mile does not have one guaranteed cash value.
Its value depends on:
- What you redeem it for
- The number of miles required
- The cash price of the alternative ticket
- Taxes and fees
- Award-seat availability
- The airline and cabin class
This is why saying “10,000 miles is always worth $X” can be misleading.
A better approach is to compare:
Cash price avoided ÷ miles required
when evaluating a particular redemption.
Miles Are Only Valuable If You Use Them Well
A high miles balance is not the end goal.
The goal is to turn those miles into rewards that you genuinely value.
Common uses can include:
- Flight award tickets
- Flight upgrades
- Partner-airline awards
- Other airline or loyalty redemptions
But availability and redemption requirements can change.
Do not collect miles indefinitely without understanding their expiry rules or having an eventual redemption plan.
Important Costs to Watch
Miles are not “free” if the strategy causes you to pay unnecessary fees.
Annual Fees
Some cards waive the first year’s annual fee but charge a fee from the second year onward.
You should evaluate whether the card remains worth keeping.
Miles Transfer Fees
Banks may charge each time you convert bank points or miles to an airline programme.
Foreign Currency Fees
Miles earned on overseas spending can look attractive, but foreign-currency card charges can reduce the value of those extra miles.
For example, Citi currently states that foreign-currency card transactions can be subject to an administrative fee of up to 3.25% on the converted Singapore-dollar amount.
This means you should compare:
extra miles earned
against:
extra foreign-currency cost paid
rather than looking only at the advertised mpd rate.
Interest and Late Fees
This is the most important one.
Never carry credit-card debt just to earn miles.
Credit-card interest can easily outweigh the value of any miles earned.
A miles strategy works best when you pay your statement balance in full and on time.
A Simple Miles Strategy
For most beginners, the basic framework can be:
Step 1 — Use a high-mpd card where you clearly qualify
↓
Step 2 — Use a general-spend card when the bonus card does not apply
↓
Step 3 — Track bonus caps and exclusions
↓
Step 4 — Accumulate bank rewards
↓
Step 5 — Transfer only when appropriate
↓
Step 6 — Redeem intentionally
The goal is not to carry ten cards.
The goal is to understand which card should be used for which transaction.
Key Takeaways
- Bank reward points and airline miles are not always the same thing.
- mpd means miles earned for every dollar of eligible spend.
- General-spend cards are simple but usually earn fewer miles.
- Bonus-category cards can earn much more, but usually come with caps and conditions.
- Bank rewards and airline miles can have different expiry rules.
- Transfer fees and foreign-currency fees can reduce the value of your miles strategy.
- Never spend more or carry debt simply to earn miles.
Next, read Understanding Miles Per Dollar to understand how 4 mpd cards, bonus caps and MCCs work.
If you already understand the fundamentals, see Best Miles Credit Cards for a Simple Setup.
Official Sources
- UOB — Preferred Visa Card
- UOB — Rewards and UNI$ expiry
- UOB — Credit-card help and miles conversion
- Citi — PremierMiles Card
- Citi — Points Transfer
- Singapore Airlines — KrisFlyer Terms and Conditions
This article is for educational purposes only and does not constitute financial advice. Credit-card terms and rewards programmes can change.