The Decoupling Calculator, Explained

Decoupling — one co-owner buying out the other's share so the freed-up spouse can buy a second property as a "first-timer" and skip ABSD — is the most over-promised manoeuvre in Singapore property. On a napkin it looks like free money: avoid 20% ABSD on a $1.8m purchase and you've "saved" $360,000. The Decoupling Calculator exists to replace the napkin with the four numbers that actually decide whether it works — because the ABSD saving is the easy part, and the financing is where most decouplings quietly fall apart.

Number one: what the transfer actually costs

Decoupling is a sale of one owner's share to the other, and that transfer is taxable. The calculator computes Buyer's Stamp Duty on the transferred share (the same 1%–6% marginal tiers as any purchase, applied to the share value), plus ABSD on the share if the remaining owner already holds another property, plus Seller's Stamp Duty if the original purchase was within the holding period, plus two sets of legal fees — because both parties are separately represented. On a $1.8m home transferred 50/50, the BSD alone is about $21,600 before anything else. This is the cost side that the napkin forgets.

Number two: the cash you actually free up

The exiting owner's share isn't pure cash. The calculator takes their share of the value, subtracts their share of the outstanding loan, and subtracts the CPF they must refund (principal plus accrued interest, back to their OA). What's left is the cash genuinely freed. And here's where the popular 99-1 structure bites: if you transfer only a 1% sliver, the exiting owner's CPF refund can be larger than the 1% proceeds — meaning they have to top up cash to complete a sale that was supposed to release money. The tool flags this trap explicitly rather than letting you discover it at the lawyer's office.

Number three: can one income carry the whole loan?

This is the number that kills more decouplings than any other. After the buyout, the remaining owner holds the property solo — and must re-qualify for a loan covering the existing balance plus the equity they're buying out, on one income. The calculator sizes that solo loan at a 75% LTV cap, a tenure of the lower of 30 years or 65-minus-age, and an instalment stressed at 4%, then works out the gross monthly income required to pass the 55% TDSR. If you enter the remaining owner's income, it tells you the shortfall directly. Plenty of couples can service a loan together and cannot service it apart — and if the remaining owner can't qualify, the whole plan stops here, regardless of the ABSD on offer.

Number four: the saving, net of all of it

Only now does the famous ABSD figure appear — honestly. The calculator computes the ABSD avoided on the next purchase as the difference between the rate the freed-up buyer would pay as a second-property owner and the rate they'd pay as a first-timer, applied to the next purchase price. Then it subtracts everything from numbers one and three to give the net saving — and a breakeven next-purchase price, below which decoupling costs more than it saves. For a citizen, the gap between a first property (0% ABSD) and a second (20%) is large, so decoupling often does win on a big enough next purchase; for smaller purchases, the transfer costs can swallow the saving entirely.

How to read it

Open the Decoupling Calculator, enter the market value, the share being transferred, the outstanding loan, each owner's CPF refund and citizenship, the remaining owner's age and income, and your intended next purchase price. Read the four sections in order — and treat number three as a gate, not a detail. A positive net saving in section four means nothing if the remaining owner can't carry the solo loan in section three.

One caveat: this is the financial picture only. Decoupling also has legal and CPF-rule consequences, and IRAS scrutinises arrangements done purely to avoid duty. Use the calculator to see whether the numbers even work; use a conveyancing lawyer to see whether the structure is sound.

Run your own four numbers at tribesg.com/tools/decoupling-calculator.

Sources: TRIBE Decoupling Calculator; BSD tiers, ABSD rates (SC 0/20/30%, PR 5/30/35%), 55% TDSR, 4% stress rate and 75% LTV per IRAS and MAS rules, as at June 2026. Informational only; not legal, tax or financial advice.

Silas Tan is a District Director at Huttons Asia and co-founder of TRIBE. This article is for informational purposes and does not constitute financial or investment advice. CEA Registration R000303I.