Every time someone hears about CardUp or iPayMy or any platform that wants you to pay a fee in exchange for miles, they ask the same two questions: “Got fees right, is it still worth it?” and “The fees only a bit – at least I get some miles out of it?”
The biggest thing that most people fail to realise is that it is whether what you get back is worth more than what you pay. This article walks through the framework I use to decide.
The Two Mistakes Beginners Make
Mistake one: “Any fee is bad.”
This is the reflexive reaction from anyone trained on no-fee cards and free GIRO. It’s wrong because it ignores the value of what you receive. A 2% fee on $1,000 is $20. If the rewards are worth $30, you’re up $10. Paying a fee isn’t bad — paying a fee for nothing is.
Mistake two: “I’m earning miles, so it’s free.”
This is the reflexive reaction from people new to miles. It’s wrong because miles cost money to earn. When you pay a 2% service fee to generate 1.4 miles per dollar, you’re literally buying miles at a per-unit cost. Whether that purchase is good depends entirely on what you do with those miles.
The right question sits between the two: what’s my cost per mile, and is that cost below what those miles will be worth when I redeem them?
The Universal Framework: Cost Per Mile (CPM)
Cost per mile is the single most important number in the miles game. It tells you how much you’re paying to earn each mile, after accounting for the service fee and the bonus miles you earn on the fee itself.
The formula:
CPM = Service Fee ÷ Total Miles Earned
Where Total Miles Earned = (Payment × (1 + Fee Rate)) × Earn Rate
Worked example: $1,000 payment, 2.0% fee, 1.4 mpd card.
- Service fee = $1,000 × 0.02 = $20
- Total amount charged to card = $1,000 + $20 = $1,020
- Miles earned = $1,020 × 1.4 = 1,428 miles
- CPM = $20 ÷ 1,428 = 1.40¢ per mile
You just bought 1,428 miles for $20. Whether that’s a good deal depends entirely on what each of those miles is worth to you.
What’s a Mile Actually Worth?
This is where individual valuations diverge. Mile values depend on how you redeem.
Generally:
- Economy class redemptions: 0.8–1.2¢ per mile of value (often worse than buying cash tickets outright).
- Premium economy: 1.2–1.8¢ per mile.
- Business class long-haul: 2.0–4.0¢ per mile, sometimes higher on peak routes.
- First class: 3.0–6.0¢ per mile, but with limited availability.
This is why miles math depends so much on how you redeem. Two people paying the same CardUp fee to earn the same miles can have wildly different outcomes — one breaks even, the other loses money, depending on what they fly.
The Milechaser Ceiling
Among established milechasers in Singapore, most won’t pay more than 1.25¢ to 1.5¢ per mile. That’s the de facto cap. But this is because they are using the miles for business class flight redemptions. The math breaks down when they use the miles to redeem for economy tickets.
This is why CardUp/iPayMy’s 2.9% standard fee doesn’t work for most cards. At 1.4 mpd, the standard rate gives you 2.01¢ CPM — over the milechaser ceiling. Promo codes aren’t a nice-to-have; they’re the entire point.
The Economy Class Trap (Why CPM Alone Isn’t Enough)
This is where most beginners lose money without realising.
Let’s walk through a real example: Singapore to San Francisco.
Option A: Pay cash. A round-trip economy ticket runs around $953.
Option B: Pay with miles bought via CardUp. Say you bought your miles at 1.3¢/mile through a platform like Citi PayAll, CardUp, or ipaymy — a reasonable rate at a good promo.
- Round-trip economy redemption: ~85,000 miles + $130 airport tax
- Cost in miles = 85,000 × $0.013 = $1,105
- Total cost = $1,105 + $130 = $1,235
The cash flight was $953. You paid $282 more by going through miles — and that’s before transfer fees.
The point: buying miles at 1.3¢ each is only a good deal if you redeem at more than 1.3¢ of value per mile. On a round-trip SQ economy redemption to SFO, the effective value lands closer to 1.1¢ — below what you paid.
Now run the same math on business class, SIN to SFO:
- Cash business class round-trip: easily $6,000–$10,000+ depending on dates
- Miles required: ~190,000 miles + ~$130 taxes
- Cost in miles (at 1.3¢): 190,000 × $0.013 + S$130 taxes = $2,600
You “spent” $2,770 to buy a $6,000+ flight. Effective value: ~3.2¢ per mile.
This is why it depends entirely on redemption strategy. Same cost per mile, completely different outcome.
One more thing. Ask yourself whether you’d pay S$2,770 out of your own pocket for a two-way business class flight, because that’s essentially what we are doing. Even though there is a perceived saving, the cash rate of a business class flight is often highly inflated and should be taken with a pinch of salt.
The Decision Flowchart
Before scheduling any CardUp/iPayMy/Citi Payall payment, run through this:
Step 1: Is your card on the eligibility list?
If no — stop. Paying a fee to earn zero rewards is the worst outcome possible. 4 miles per dollar cards are generally excluded.
Step 2: What’s your CPM at the available promo rate?
Use the formula above. Compare to your personal ceiling. Most business class milechasers cap at 1.5¢. Stricter milechasers cap at 1.25¢. Your call.
Step 3: How will you redeem these miles?
- One way or two way?
- Business Class? First Class?
Step 4: Any promo codes you can use?
If you somehow ended up at standard rates with no promo applied, almost any miles card fails the math. Wait for a promo, or skip.
Bottom Line
Citi Payall, CardUp and iPayMy are great tools to buy miles for a premium cabin experience. I have personally used this method to get miles for business class and first class redemption tickets. They make sense when:
- Your card earns rewards on the platform.
- You’re using a promo code (not standard rates).
- Your CPM clears your personal ceiling — most milechasers stay between 1.25¢ and 1.5¢.
- You have a plan to redeem the miles for value above your CPM (usually premium cabins).
If any one of those four is missing, GIRO the bill and move on. Send this to your friend who paid a fee to redeem their miles for an economy flight.
