“Rent is paying someone else's mortgage” is memorable, but it is not a full comparison. Renting buys flexibility. Buying can provide housing stability and an ownership stake over a long period. Neither is automatically the financially superior choice; the answer changes with your time horizon, cash reserve and ability to cope with a less forgiving monthly budget.
The deposit does not disappear—but it is no longer liquid
The down payment becomes part of the property equity, alongside stamp duty, legal fees, agency commission and mortgage-related costs. Some of that is recoverable only when the home is sold, and selling itself has cost and timing risk. A renter may retain or invest the equivalent capital, though investment returns should be treated as an assumption, not a promise.
The first question is therefore not “can I raise the deposit?” but “after completion, what cash remains for the next two years?” A household that can fund the deposit but has almost no emergency reserve is taking a different risk from one that can do both.
Add the owner costs that do not appear in the monthly instalment
An owner may face management fees, government rates or rent, insurance, repairs, renovation, appliances and irregular building works. Some costs are monthly; others arrive unexpectedly. List them separately from the mortgage payment. The same applies when selling: transaction costs matter more when the expected holding period is short.
Time horizon and flexibility are financial inputs
If a job, school choice or family situation may require a move within a few years, the ability to leave at the end of a tenancy has value. If you expect to stay for a long time, have stable income and maintain a meaningful reserve, ownership's stability may matter more. Do not use one property-price growth assumption to decide the entire question: also test flat prices, a shorter holding period and conservative returns on the deposit.
Mortgage and stamp-duty rules can change. Start with the HKMA's mortgage information and IRD individual tax information, then check the current transaction documents and professional advice relevant to your case.
Use the Rent vs Buy Calculator for like-for-like holding-period scenarios, then the Mortgage Calculator to test different prices, deposits, terms and rates. If the home is an investment property, use the Rental Yield Calculator separately—owner-occupier affordability and investment yield answer different questions.
The decision is strongest when it still works in an ordinary, slightly difficult year, not only in the best property-market scenario.