How interior designers charge in Singapore: fee models explained

Singapore regulates who may build, not what a designer may charge. No public register publishes design fees, no statute sets a scale, and the two words "design fee" cover at least five different commercial arrangements. The question behind "how much does an interior designer cost in Singapore" is really two questions wearing one coat: what the design work costs to produce, and which structure is used to recover it.

The five fee structures Singapore firms actually use

A percentage design fee is calculated on the value of the construction works, so the fee moves with the build. The structure suits a project where scope is genuinely open at the first meeting and no deliverable list can be written yet, because the fee scales with whatever the project turns out to be. The trade-off is plain: a fee that rises with spend rewards specifying upward, so the homeowner has to police scope rather than trust it.

A fixed design fee is quoted as a sum against a written deliverable list — measured drawings, layout options, elevations, joinery details, a finishes schedule, a stated number of revisions. Decoupling the fee from build value removes the upward-specification incentive and converts the argument from "how much" into "how many revisions", which is a far easier argument to settle before signing. The failure mode is a deliverable list written loosely enough that the third layout revision arrives as a variation.

A design-and-build contract folds the design cost into the construction price and shows no separate design line at all. One counterparty owns both the drawings and the site, which is the main reason homeowners pick it, and the design cost remains real but invisible — recovered inside carpentry, tiling and finishing rates. Comparing two such contracts on the bottom line compares two different bundles rather than two prices.

Free design conditional on awarding the build is the fourth structure, and the word "free" is doing work it cannot support. Design labour under that arrangement is financed by the build margin and recovered only if the contract is signed, which is why firms offering it usually want a booking sum, a deposit or a signature before drawings leave the office. What a design stage should cost against a defined deliverable list belongs in writing: TO FILL: how Noble structures its design fee — percentage of works, fixed sum, or absorbed into the build contract — and what triggers each.

An hourly or retained consultancy fee is the fifth and rarest arrangement in the residential market, and it is the honest structure for advice without delivery: a second opinion on another firm's drawings, a layout review before an offer to purchase, or a specification audit on a quotation already received.

What a design fee cannot buy, whatever it is called

Certain drawings are reserved by statute to registered professionals, and no fee structure changes that. The Architects Act 1991 states the restriction directly:

"Subject to the provisions of this Act, a person must not draw or prepare any architectural plan, drawing, tracing, design, specification or other document intended to govern the construction, enlargement or alteration of any building or part of a building in Singapore unless the person — (a) is a registered architect ... (b) is doing so under the direction or supervision of a person mentioned in paragraph (a); or (c) is exempt under section 36 from this section."

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— Architects Act 1991, section 10(1)

Section 11 of that Act attaches a commercial consequence to the restriction. A person who is not authorised by the Act to supply architectural services is not entitled to demand, claim or sue for or recover any charge, fee or remuneration for them, and section 11(2) allows a person who paid another for conduct in contravention of section 10 to recover the money in a court of competent jurisdiction — but only if the payer did not know, and had no reason to believe when paying, that the conduct was in contravention.

HDB applies a parallel rule inside flats, stating on its permit page that certain renovations require the flat owner to engage a Qualified Person to certify or supervise the work, with the Professional Engineers Board register given as the list to check (HDB, Application for a Renovation Permit). A Qualified Person's fee is a separate professional fee and should appear as its own line, not as a discount item folded into a design package.

What a percentage fee does that a fixed fee does not

Percentage fees make the designer a partner in the size of the build, which cuts both ways. The upside is real on an open-scope project: a designer paid on outcome has no reason to under-specify waterproofing or substrate to protect a fixed fee, and the structure survives a scope that doubles between the first sketch and the permit. The downside is equally real, because every specification decision now has a fee consequence attached to it, and the homeowner cannot see which decisions were driven by that.

Fixed fees put the risk of a slow project on the designer, which is exactly why the deliverable list matters more than the number. A firm quoting a fixed design fee is pricing an estimate of hours, and hours are consumed by indecision, by site discoveries after demolition, and by revisions that were never scoped. Two protections belong in the fee clause: a named list of what is included, and a written rate for what is not.

Design folded into a build contract removes the comparison problem for the homeowner and creates a different one. Nobody can tell whether the drawings are subsidising thin build rates or the build rates are subsidising thin drawings, and the only way to find out is to compare the specification line by line — board grades, hardware brands, membrane type, tile adhesive class — rather than the totals.

GST, and the nine per cent that arrives after the fee

IRAS states that standard-rated supplies carry 9% GST and that a business must register for GST when its taxable turnover exceeds $1 million, while a business below that threshold may still choose to register voluntarily (IRAS, Goods and Services Tax: What It Is and How It Works). A design fee quoted by a GST-registered firm and the same fee quoted by a firm under the threshold are not the same number on the day the invoice arrives. Ask for the figure inclusive of GST and for the firm's registration status in writing, because IRAS also states that only GST-registered businesses can charge and claim GST.

Tying the fee to something a homeowner can check

Accreditation converts several fee promises into audited obligations. CaseTrust requires accredited renovation businesses to adopt the CaseTrust Standard Renovation Contract, to collect payments in phases upon agreed milestones, to cap initial deposits at a maximum of 20% of the total cost, to provide a workmanship warranty of 12 months from the completion date of the works, and to purchase a deposit performance bond safeguarding deposits against closure, winding up and liquidation (CASE, CaseTrust accreditation for renovation businesses). Noble Interior Design Pte. Ltd. is listed in HDB's Directory of Renovation Contractors (DRC Ref: HB-12-5230A, UEN 201722629H) and is CaseTrust-accredited.

Obligations of that kind exist because the money risk in this trade is documented rather than theoretical. CASE recorded 787 complaints against renovation contractors in 2025, down 18.2 per cent from 962 in 2024, and reported prepayment losses in the industry falling 73.8 per cent to $190,667 from $728,813.76, with renovation contractors still the second-largest industry by prepayment losses in 2025 behind beauty, per the CASE media release of February 2026. CASE separately reported that approximately 97 per cent of the 962 renovation complaints it received in 2024 were against non-CaseTrust accredited contractors (CASE media release, February 2025).

Estimate creep, and the line the law draws

An estimate given verbally and a fee charged later are governed by consumer legislation, not only by goodwill. The Consumer Protection (Fair Trading) Act 2003 makes it an unfair practice for a supplier, in relation to a consumer transaction, to make a false claim or to do anything specified in its Second Schedule, and Part 1 of that Schedule includes a paragraph aimed squarely at fee drift:

"Charging a price for goods or services that is substantially higher than an estimate provided to the consumer, except where the consumer has expressly agreed to the higher price in advance."

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— Consumer Protection (Fair Trading) Act 2003, Second Schedule, Part 1, paragraph 10

The same Schedule also covers free items: offering gifts, prizes or other free items in connection with the supply of goods or services, where the supplier knows or ought to know that the items will not be provided or provided as offered, is listed at paragraph 19 as a specific unfair practice. A "free design" promise is therefore worth writing down with its conditions attached, because a promise written down is a promise that can be tested against that paragraph.

Choosing a structure, including when the cheapest is right

A fixed design fee against a named deliverable list is the safest default for a defined job — a resale flat refresh, a kitchen and two bathrooms, carpentry within an existing layout. Scope is knowable at the start, revisions are countable, and the fee stops moving once the list is agreed.

A percentage fee or a design-and-build contract earns its keep where layout changes, where trades overlap heavily, or where the programme is tight against a move-in date, because the coordination that prevents a regraded drain or a rebuilt carcass is worth more than the fee that buys it. Small, visually simple jobs rarely need either.

One test separates the structures quickly. Ask each firm to put in writing what the design fee includes, how many revisions it covers, the hourly or per-drawing rate beyond that, whether it is offset against the build if the build is awarded, and what happens to the fee and the drawings if it is not.