When Topping Up a Free Night With Points Is the Only Smart Amex→Bonvoy Transfer

Someone on X put it plainly this week. Moving American Express points into Marriott Bonvoy is usually a weak trade. The exception: topping off a free night certificate for a stay you’d book anyway.

Yes. That’s the only version of this transfer I actually like.

I’ll keep this in plain English. No points-bro speak.

What a free night certificate is

A free night certificate (sometimes called a free night award) is a night Marriott will cover up to a points cap — often from a card anniversary. Mine comes with the Marriott Bonvoy Brilliant Amex issued in the US. Think of it as a coupon for one hotel night, priced in Bonvoy points, not cash.

If the room you want costs more points than the certificate covers, Marriott lets you add Bonvoy points to close the gap. That’s the top-off.

Since March 12, 2026, you can top off one certificate with up to 25,000 Bonvoy points. So a certificate that covers up to 35,000 can stretch toward a 60,000-point night, if the math works. Watch the expiry — these don’t stretch forever — and know resort fees and taxes still hit cash. The certificate does not eat those.

Why Amex → Bonvoy is usually a bad deal

Amex Membership Rewards can move into a lot of airline and hotel programs. Marriott is rarely the high-value path. You give up flexible Amex points for hotel points that are sticky and often weaker per point.

So the rule of thumb stays: don’t dump Amex into Bonvoy “because Marriott.” Find the room first. Then transfer only what you need.

Someone noted a temporary sweetener — a 35% bonus on Amex transfers into Bonvoy through December 10. That softens the math. It still doesn’t make random dumping smart. It makes a planned top-off less painful.

The W Hong Kong pattern

I hold Titanium Elite with Marriott, and I use the Brilliant free night when the hotel I already want sits just above the certificate cap.

Recent example: a night at W Hong Kong on a free night award, with a 16,000-point Bonvoy top-off on top of the certificate. That’s inside the 25,000 top-off ceiling. The next night on that trip was cash. Same hotel, two different payment shapes — certificate-plus-top-off, then cash — because that was the cleanest way to cover the dates.

Titanium helps with the stay (late checkout habits, upgrades when they happen). It does not change the top-off math. The certificate and the points do that.

I’ve written about hotel breakfast at places like W as a lived stay, not a points lecture. Same hotel family. Different question here: how you pay for the night without lighting Amex points on fire.

The only smart transfer (for me)

1. Pick the hotel and dates you’d book anyway.
2. See if a free night certificate covers the night, or almost covers it.
3. If the gap is small — and under the top-off limit — move only the Amex points you need into Bonvoy (bonus window or not).
4. If the gap is huge, pay cash or pick a different night. Don’t force a bad transfer to “use” the certificate.

That’s it. Topping up a free night is the rare Amex→Bonvoy move that feels like finishing a booking, not gambling with a currency conversion.

Stay tuned… I’ll keep translating card-and-points tricks into the boring version that actually books a room.