GUIDES & INSIGHTS · GUIDE 006

One title, two front doors. The tax is the point, and the rent is the reason.

A dual-key is a single strata unit divided into two lockable halves — usually a main apartment and a studio — on one title, with one set of duty payable on it. Buy one and you can live in the larger side and let the smaller one, which is the same outcome as owning two properties without being taxed as though you own two. On a $2.2 million purchase that difference is $155,100 in duty alone. It is a real structure with a real arithmetic case, and it is also sold with two claims that are not true.

Farhan Adenan · 5 Sep 2026 · 12 min read

Duty rates are IRAS published rates for a Singapore citizen, current as at 5 September 2026. Yield, rent and value figures are medians from the POV resale dataset of 1,474 projects, 1,105 of them carrying a rent figure, as at 15 July 2026. Asking prices in Exhibit 4 are from POV new-launch availability data as at 15–20 August 2026. All arithmetic is ours and is shown so you can reproduce it.

A dual-key unit is one strata title subdivided into two self-contained halves, each with its own lockable entrance, kitchenette or wet point, and bathroom. Typically a two- or three-bedroom main unit and a studio, sometimes sharing a private lobby. They were built for multi-generational households — adult children, elderly parents, a helper — and were then adopted by investors for a reason the brochures are perfectly open about.

It is one property. One title, one mortgage, one set of stamp duty, one entry in your name at IRAS. That is the entire mechanism and everything below follows from it.

And here is the thing most pitches leave out, so take it now rather than later: owning a dual-key does not leave you with a spare property allowance. It is one residential property, so your next purchase is a second property and carries the full 20% ABSD for a citizen. A dual-key defers that problem elegantly. It does not delete it.

Take a Singapore citizen who wants somewhere to live and something to let, with roughly $2.2 million to deploy, and who owns nothing yet.

Buy one dual-key at $2,200,000. It is a first property, so there is no Additional Buyer’s Stamp Duty at all. Buyer’s Stamp Duty is $79,600. That is the whole duty bill.

Buy the two halves separately — a 2-bedder at $1,500,000 to live in, a studio at $850,000 to let. The 2-bedder is your first property: BSD $44,600, no ABSD. The studio is your second: BSD $20,100 plus ABSD at 20%, which is $170,000. Total duty $234,700.

Add the price difference and the gap widens again. Two separate units at $1.5m and $850k come to $2,350,000 against $2,200,000, so the buyer spends $150,000 more on price and $155,100 more on duty.

The income case is usually asserted — “rent out the studio, let it pay your mortgage” — without the number that makes it work. Here is the number.

Across the 1,105 projects in our resale dataset carrying a rent figure, gross yield is not flat across sizes. It falls as the unit gets bigger, and it falls a long way.

So the structural argument is this. A large unit bought whole earns you about 2.95% if you let all of it, and nothing at all if you live in it. A dual-key lets you occupy the large half and let the small half — and the small half earns like a small unit, not like a slice of a big one. On the median small-unit rent of $3,118 a month, that is $37,416 a year, or $187,080 across five years, gross, while you live in the rest.

Rent does not scale with price. A dual-key is a way to exploit that inside one title.

Two honest qualifications, because this is the number people will act on. First, the 4.11% is a project-level median for small units, not a measurement of dual-key studios specifically — we have no dual-key flag in the resale data and cannot isolate them. Second, a dual-key studio may well let for less than a free-standing studio of the same size: it often shares a lobby, has no separate address, and a tenant who wants independence can tell. Treat $3,118 as the ceiling of what the mechanism offers rather than the figure you will bank.

They are not scarce. The claim that developers have stopped building dual-key units is repeated constantly and it is simply not so. As at mid-August, seven Singapore projects had unsold dual-key stock on the market — TMW Maxwell, ELTA, One Marina Gardens, The Orie, OCHO, The Hillshore and The LakeGarden Residences — several of them 2025 and 2026 launches. We found no URA rule prohibiting or capping them.

And they are not priced at a premium. The standard line, repeated by the large portals, is that a dual-key costs up to 25% more per square foot than a comparable unit. We tested it the only fair way: within each project, comparing the dual-key layout against that same development’s other layouts.

Exhibit 4. Six of seven ask less per square foot than their own project’s other layouts, with a median of 4.2% below and a spread from −11.5% to +6.4%. Read this carefully: these are developer asking prices on unsold stock, not transacted prices, and seven projects is a small sample — a within-project comparison is the fairest cut available to us, not a market-wide finding. What it does establish is that the blanket claim of a 25% premium does not describe what is currently on the shelf. Source: POV new-launch availability, 15–20 Aug 2026.

Our reading of the discount, offered as a reading rather than a finding: the market is pricing the exit. A dual-key appeals to a narrower set of buyers than a plain three-bedder, so it clears at a slightly lower number. If that is right, then the discount at entry is not a bargain — it is a fee you are paid up front for accepting a harder sale later, and you will pay it back when you sell.

On resale dual-key units specifically, which is where most of these transact, we would expect that discount to be wider: older stock, an even narrower pool, and layouts that have dated. We cannot show you that, because our resale data carries no dual-key flag. It is the honest gap in this article.

1. You cannot sell half. One title means one transaction. If you want out of the studio — the tenant is a nuisance, the yield disappoints, you need the capital — the only way out is selling the whole thing. A two-property owner can sell one and keep the other. You cannot.

2. Your next purchase is still a second property. Worth repeating because it is the most common misunderstanding. The dual-key does not bank you an ABSD-free slot for later. Buy anything after it and you pay 20% as a citizen, 30% as a permanent resident, 60% as a foreigner.

3. The rent is taxable, and the property tax treatment changes. Rental income is assessable income. And the owner-occupier property tax rates apply only to the portion you actually occupy — letting part of your home can move the let portion onto the higher non-owner-occupier schedule. How that is assessed depends on the specific arrangement, so get it in writing from IRAS before you model the net yield, not after.

4. The exit pool is genuinely narrower. Your buyer must want the layout: a multi-generational family, or another investor running the same strategy. A young couple looking for a three-bedder will walk past it, and there are many more of them. In a soft market that is where it shows.

None of these makes a dual-key a bad purchase. They make it a purchase with a specific shape, which suits a specific household and is wrong for the rest.

If you want a home and an income from one purchase

The saving is real, and it is the reason to do this

If you own nothing yet, want somewhere to live and something that pays, and expect to hold for a long time, the duty arithmetic is decisive: $155,100 not spent, and a let side that earns like a small unit rather than like a slice of a big one.

Underwrite it on the studio being empty two months a year and on the rent being below a free-standing studio’s, because it probably will be. If it still clears, this structure does something no pair of separate purchases can do at the same price.

If you might need to sell one of them

One title is the whole trade, and it binds in both directions

If there is a real chance you will want to release one half — to fund a business, to help a child buy, to cut exposure in a soft market — then two separate properties are worth the $305,100 they cost more. Optionality is the thing you are selling when you buy a dual-key.

The same applies if you are buying with a five-year horizon. The entry discount and the narrower exit pool point the same way on a short hold, and neither is in your favour.

GUIDES & INSIGHTS · FRAMEWORK 05

The Yield Play. Computed on a number you never paid.

Why the advertised yield overstates it, and what belongs in the denominator.

MARKET & POLICIES · INSIGHT 005

Where the yields are actually real

The projects where rental income covers the position — measured, not advertised.

Dataset — POV resale dataset, 1,474 projects (1,105 with a rent figure), as at 15 July 2026. POV new-launch availability, as at 15–20 August 2026. Duty rates as published by IRAS, current as at 5 September 2026.