A Membership Rewards transfer bonus on one BA reward seat: how many points it actually saves, and when it makes no difference

A Membership Rewards transfer bonus to The British Airways Club saves you points only on the Avios you actually have to move. So the starting figure is the seat’s Avios price minus what is already in your BA Club account, not the seat price itself. Work out how many Membership Rewards (MR) points that gap needs at the standard ratio and again at the bonused ratio, round both up to the transfer increment, and the difference is your saving. The cash for taxes, fees and carrier charges is the same either way, so it drops out of the sum.

The bonus saves nothing when your BA balance already covers the seat, when the gap is small enough that rounding swallows the bonus, when the offer’s terms exclude your transfer, or when qualifying for it would cost at least as many MR points as transferring without it. Amex transfers to airline partners can’t be undone and can only go to an account in your own name, so the bonus is only worth calculating once the exact seat is on screen.

Why the headline percentage overstates the saving

Two things shrink a bonus between the advert and your booking.

First, the bonus never touches Avios you already hold. If a seat costs 50,000 Avios and you have 20,000 in BA Club, the bonus applies to a 30,000 Avios transfer, not to the 50,000 Avios seat. The more Avios you already have, the less the bonus can do on this booking.

Second, a bonus percentage is not the same as a percentage off your MR points. A 30% bonus means each MR point buys 1.3 times as many Avios, so the MR needed falls to 1 ÷ 1.3 of the original: a cut of about 23%, not 30%. In general, the cut is bonus ÷ (1 + bonus). Rounding to a transfer increment can then move the saving either way. With 1,000-point steps, a 1,100 Avios gap needs 2,000 MR without the bonus but only 1,000 with it. That’s why the steps below work from rounded figures rather than the percentage.

The assumptions behind the numbers here

I haven’t been able to retrieve the current Amex UK to BA Club transfer ratio, the transfer minimum or increment, or the terms of any live BA Club bonus. So every ratio, bonus rate, seat price and balance below is illustrative:

• A base ratio of 1 MR point to 1 Avios is assumed for the arithmetic. Use the ratio shown in Amex’s BA Club partner details instead.
• Transfers are assumed to go in 1,000-point increments, with no minimum above the first 1,000. Confirm the transfer minimum and increment in Amex’s BA Club partner details.
• The bonus is assumed to apply at a flat rate to the whole transfer, with no threshold, cap or registration step. Real terms may differ.
• The seat’s Avios price and cash charges are assumed not to change between pricing and booking, and you are booking the standard reward at the full Avios price shown.

If your real figures differ, the method still holds; only the inputs change.

Three numbers to read off the booking screen

BA reward flights cost Avios plus a separate cash amount for taxes, fees and carrier charges, and they are only bookable where there is availability on BA, Iberia, oneworld and other partner airlines. So the calculation starts with a seat you can actually book, not a route you hope to find space on.

1. The seat’s Avios price, for the exact flight, cabin and number of passengers.
2. Your current BA Club Avios balance, as it stands now, excluding Avios you expect to earn.
3. The cash charges. Note them, but they don’t enter the bonus calculation. They matter to whether the seat is worth booking at all, which is a separate question.

The calculation in four steps

Step 1: find the shortfall

Shortfall = seat Avios price − current BA Club balance. If the answer is zero or negative, stop. You have nothing to transfer and the bonus is irrelevant to this booking.

Step 2: MR points needed without the bonus

Divide the shortfall by the base Avios-per-MR ratio from Amex’s partner details, then round up to the transfer increment. If Amex’s transfer minimum is higher than that rounded figure, use the minimum instead. That means moving more Avios than this seat needs.

Step 3: MR points needed with the bonus

Divide the shortfall by the base ratio × (1 + bonus rate), then round up to the same increment. Check this figure against the transfer minimum on its own: if it falls below the minimum, use the minimum, even if Step 2 didn’t need it. If both columns end up on the minimum, the bonus saves no MR points and only adds surplus Avios. Multiply the final MR figure by the bonused ratio to see how many Avios actually land. Anything above the shortfall is surplus that stays in BA Club.

Step 4: the saving

MR saved = Step 2 − Step 3. To put a value on it, multiply by your own pence-per-MR figure, set before you saw the offer so the bonus doesn’t nudge it upward. The surplus Avios from Step 3 are worth something, but value them at a cautious floor rather than at the inflated rate the bonus implies. Avios don’t expire as long as you collect, use or purchase at least one every 36 months, so a small surplus isn’t lost; it just isn’t doing anything yet.

Worked example A: a 30,000 Avios gap on a 50,000 Avios seat

Hypothetical: the seat costs 50,000 Avios, you hold 20,000, the base ratio is 1:1, the bonus is 30% and transfers go in 1,000-point steps.

	No bonus	With 30% bonus
Shortfall	30,000 Avios	30,000 Avios
Raw MR needed	30,000	30,000 ÷ 1.3 = 23,077
Rounded MR transfer	30,000	24,000
Avios credited	30,000	31,200
Surplus Avios	0	1,200

The saving is 6,000 MR points: 20% of the unbonused transfer once rounding is applied, against a 30% headline. You also end up with 1,200 spare Avios.

Now run the same seat for someone with an empty BA Club account. The full 50,000 Avios is the shortfall: 50,000 ÷ 1.3 = 38,462, rounded up to 39,000 MR, crediting 50,700 Avios. That saves 11,000 MR points. Same seat, same bonus, but the reader who already holds 20,000 Avios saves 5,000 fewer MR points. Neither reader is worse off, but anyone sizing up the bonus by the seat price will expect more than they get.

If you value MR points at, say, 1p each (an illustrative figure, not a recommendation), the 6,000 MR saving is worth £60. Use your own number.

Worked example B: a 2,000 Avios gap where rounding takes the saving

Same assumptions, but you’re only 2,000 Avios short.

• Without the bonus: 2,000 MR.
• With the bonus: 2,000 ÷ 1.3 = 1,539, rounded up to 2,000 MR, crediting 2,600 Avios.

The saving is zero. You transfer the same number of MR points either way; the bonus just adds 600 surplus Avios. That’s mildly useful, but not a reason to time the booking around the offer. Small shortfalls are where rounding most often erases a bonus, and the larger the transfer increment, the bigger the gap has to be before the bonus produces any MR saving at all.

Why the cash charges drop out, and when they don’t

BA prices the seat, not where your Avios came from. In a straight comparison between a bonused and an unbonused transfer for the same reward, the taxes, fees and carrier charges are identical on both sides and cancel out. Neither of the sources I’ve used states this outright; it follows from BA pricing a reward as Avios plus a cash amount.

That changes if you switch to a different version of the booking. BA lets members who are short buy Avios or pay a cash amount to reduce the Avios required. A cash-to-reduce booking changes both the Avios price and the cash, so it’s a different booking with a different shortfall. Run the four steps again on its own figures rather than mixing the two. If you’re weighing BA’s buy-Avios and cash-to-reduce options against each other, our guide to closing a BA Avios gap covers that comparison. I can’t tell you here whether buying the gap from BA beats a bonused transfer, because I don’t have BA’s current pricing for either option.

When the bonus makes no difference

Any one of these means the bonus saves nothing on this seat.

1. Your BA balance already covers the seat. No shortfall, no transfer, no saving.
2. Rounding absorbs it. As in example B, if the bonused and unbonused transfers round to the same MR figure, or both land on the transfer minimum, the saving is zero.
3. The terms exclude your transfer, or qualifying costs too much. Registration, minimums, caps or dates can rule it out. Amex notes that partners often promote bonus offers, but the conditions belong to each offer, so read the one in front of you. If there’s a qualifying threshold, compare it with your bonused transfer from Step 3, not Step 2. For an Avios threshold, check whether the terms count base or bonused Avios, then work out the MR transfer needed to reach it. If that qualifying transfer is above Step 3 but still below Step 2, topping up to it still saves MR: in example A, a 25,000 MR threshold would cost 25,000 MR instead of 30,000, saving 5,000 and leaving 2,500 surplus Avios. If qualifying costs as much as Step 2 or more, the bonus saves nothing, so don’t top up.
4. The bonus Avios arrive too late. If the terms credit bonus Avios separately and after the base transfer, and the seat has to be booked before they land, you’d need to transfer the full unbonused amount to secure it. The bonus then becomes surplus rather than a saving.
5. The only gain comes from moving extra for other trips. Avios topped up for a future trip while the rate is good aren’t part of this seat’s saving. Amex says transfers to frequent flyer partners are irreversible, even if the booking you wanted can’t be made, so Avios moved for a seat you haven’t found are a commitment, not a saving on this booking. The case against speculative transfers covers that decision, including its narrow exception for a bonus in a programme you’d genuinely use anyway.

A note on changing your mind later: BA says reward flights can be changed or cancelled up to 24 hours before departure for a fee without losing your Avios. Those Avios go back to BA Club, not to Membership Rewards, so a cancellation doesn’t undo the transfer.

Before you press transfer

Answer these from Amex’s BA Club partner details and the live offer terms, because I can’t answer them for you:

• What base ratio and transfer increment apply to BA Club?
• Does the bonus apply to the whole transfer, or only above a threshold or up to a cap? Is any threshold set in MR points, base Avios or bonused Avios? Does it need registering?
• Are bonus Avios credited with the base transfer or later, and how are fractions rounded?
• Does the offer count your transfer from when you submit it or from when it credits, and does that fit the seat’s booking window?

Then the sequence:

1. BA Club is linked to Membership Rewards, and the account is yours. Amex only allows transfers into an account in your name, so you can’t top up a partner’s BA Club account directly. If it isn’t linked yet, start the link now: Amex says to allow up to 14 days to verify it. Once it’s verified, recheck the seat’s price and availability and the offer’s dates before going further.
2. The exact seat is live and priced.
3. You’ve allowed for timing. Once linked, transfers usually complete within five working days, though Amex says this varies by partner and can be much faster. That’s a usual time, not a promise, and availability can change while you wait.
4. You transfer only the rounded shortfall for this seat, or the qualifying transfer worked out under “The terms exclude your transfer” above, if that still costs fewer MR points than Step 2.

If you’re short of MR points as well as Avios, Amex lets you buy up to 10,000 extra points a year. Amex says limits may change, so check the current limit and price with Amex before comparing it with buying the gap from BA.

The bonus is a real saving when you have a large Avios gap on a seat you can book today and the offer’s terms fit your transfer. It’s worth nothing when your balance covers the seat, rounding swallows it, the terms rule you out, or qualifying would cost as many MR points as transferring without it. Work from the shortfall, not the seat price, and the number you get is the one you actually save.