How to calculate the value of a transfer bonus

How do you convert a bonus percentage into extra partner points?

Start with the number of points you intend to move and the bonus rate written as a decimal. Bonus points are the transfer size multiplied by that rate, and the total landing in the partner account is the transfer size multiplied by one plus the rate. At a 30% bonus, 20,000 points produce 6,000 bonus points and a balance of 26,000 in the partner programme [6].

The same multiplication works for an odd transfer size. Moving 17,400 points during a 25% bonus adds 4,350 bonus points for a total of 21,750. Doing the sum in this order keeps the bonus attached to the points that actually moved, rather than to a round number you hoped to move.

Round only at the end, and round by the rules of the programme receiving the points: once a transfer completes, the balance is held under that partner programme's terms [6]. If the offer itself sets a cap or a minimum transfer, apply it to the transfer size first and then run the multiplication.

What is an effective transfer ratio?

The transfer ratio is how many partner points one source point buys at the ordinary rate; the effective ratio simply folds the bonus in. Write the base ratio as partner points per source point, then multiply by one plus the bonus rate. A 1:1 base with a 30% bonus gives 1.3 partner points per source point, and 10,000 source points become 13,000 partner points.

Ratios below 1:1 work the same way. A base of 0.5 partner points per source point — two points moved for one partner point — becomes 0.65 with a 30% bonus. Expressing the result per 1,000 points makes it easier to compare partners: 1,000 source points at 0.65 return 650 partner points.

The effective ratio is the number to carry into the rest of the calculation, because it already answers the only question that matters for a redemption: how many partner points will be sitting in the account.

How do you get cents per partner point after rounding?

The cents-per-point result is the total cost of the source points, converted to cents, divided by the partner points actually received. Where the source points are bought rather than earned, the cost per mile is the package price divided by the miles in the package. Lotusmiles reinstatement and extension are sold in packages of 500 miles, at 125,000 VND in Vietnam excluding VAT and US$5 outside Vietnam, and the programme states that fees and terms may change [7] [8].

Adding a bonus divides that cost by one plus the bonus rate. A mile that costs 1 US cent becomes roughly 0.77 US cents per mile once a 30% bonus is applied (1 ÷ 1.3), and a mile costing 250 VND becomes about 192 VND. The bonus rate itself comes from the offer you are acting on, so the calculation needs that percentage and the offer's own conditions before it means anything.

Minimums change the divisor. The Lotusmiles purchase screen shows the smallest package of 500 miles by default and is adjusted up or down in steps, so the miles bought come in whole 500-mile blocks [7] [8]. If the points you need do not divide evenly into a block, round up to the next whole block, multiply the number of blocks by the package price, and divide that total by the partner points the blocks produce after the bonus. Every issuer sets its own minimum transfer and its own rounding, and those rules sit in that issuer's terms.

Exceptions and limits

• Who can transfer. American Express describes the facility as open to eligible Membership Rewards customers and to participating frequent flyer or hotel loyalty programmes, so neither the transfer nor a bonus attached to it is available to every cardholder or to every partner [6].
• Linking and names. The Rewards Account must be linked to the partner account, and the name on the card must match the name on the partner account for the link and the transfer to succeed [6]. A partner account held by an Additional Card Member can be linked only if that card was issued at least 90 days before linking [6].
• No way back. All points transfers are final and cannot be reversed, and American Express advises checking award availability and the points needed before completing a transfer [6]. A bonus therefore adds points to a balance you cannot send back if the redemption falls through.
• The partner's rules take over. Once points reach the partner account they are subject to that programme's terms and conditions, which govern its minimums, rounding and validity [6].
• Packaged miles carry conditions. Reinstated Lotusmiles miles are valid for six months from the successful transaction, extended miles for twelve months from the first expiry date, and both carry no status value and are non-refundable [7] [8]. Extension has to be requested within six months before the expiry date, while reinstatement applies within six months after it [7] [8].
• Offers move. Before committing points, confirm on the transfer bonus calendar which offer is running for the partner you want and on what dates, then re-run the arithmetic with that rate.

Frequently asked questions

How do you turn a percentage transfer bonus into extra points?

Multiply the transfer size by the bonus rate to get the bonus points, then add them to the transfer. A 30% bonus on 20,000 points adds 6,000 points and leaves 26,000 in the partner account [6].

What is an effective transfer ratio?

It is the ordinary ratio multiplied by one plus the bonus rate. A 1:1 ratio with a 30% bonus becomes 1.3 partner points per source point, so 10,000 source points deliver 13,000 partner points.

Why does rounding change the cents-per-point result?

Because you pay for whole blocks even when you need a few extra points. Lotusmiles sells reinstatement and extension in 500-mile packages and displays the smallest package by default [7] [8], so dividing the total paid by the points actually received gives a higher cost per point than dividing by the points you intended to buy.

Can a transfer be undone if the bonus does not appear?

American Express states that all points transfers are final and cannot be reversed, and recommends checking availability and the points required before transferring [6]. The bonus rate and the balance should therefore be confirmed before the transfer is submitted.

Related pages

Transfer bonus calendar, transfer ratio, cents per point, and the full frequent flyer glossary.

Sources

Sources checked on 18 October 2026. Airline and bank transfer schemes other than American Express Membership Rewards and Vietnam Airlines Lotusmiles are not covered here.

1. American Express: How do I transfer Membership Rewards points?, checked 18 October 2026
2. Vietnam Airlines Lotusmiles: reinstating expired bonus miles, checked 18 October 2026
3. Vietnam Airlines Lotusmiles: extending bonus miles, checked 18 October 2026