Small bathroom renovation: cost, layout and what not to squeeze in
A small NZ bathroom costs $4,000–8,000 to upgrade and $15,000–25,000 to fully renovate (Superior Renovations), because the trades cost much the same in a small room. Layout choices that make 3–5 m² work.
By Bathroom Renovation NZ
Key takeaways
- Superior Renovations' NZ averages for a small bathroom (under about 5 m²): $4,000–8,000 for a minor upgrade, $15,000–25,000 for a full renovation, $25,000–35,000 for a custom one with layout changes.
- A small bathroom costs less than a large one, but not proportionally less: the plumber, electrician and waterproofer are fixed costs whatever the floor area.
- Moving a fixture is the expensive decision in a small room: $2,000–6,000 on its own (CheckMyBuilder).
- Bath out, shower in is the most common small-room change, and it does not need consent if the number of sanitary fixtures in the house stays the same.
- Every bathroom in a rental still needs an extractor fan that vents outside under the healthy homes standards.
A small bathroom, under about 5 m², costs $4,000–8,000 for a minor upgrade and $15,000–25,000 for a full renovation with retiling, by Superior Renovations' New Zealand averages. That is less than a standard room but not in proportion to its size, because most of the cost is trades and waterproofing, not tiles. The way to keep a small room affordable is to leave the toilet and waste where they are and spend on the things that make the space feel larger.
How much does a small bathroom renovation cost?
| Scope | Typical range | What it covers |
|---|---|---|
| Minor upgrade | $4,000–8,000 | Fixture swaps and paint, tiles left on |
| Full renovation | $15,000–25,000 | Demolition, all trades, new membrane and retiling |
| Custom renovation | $25,000–35,000 | Layout changes and premium finishes |
Superior's page does not state whether these include GST. For a standard-sized room, CheckMyBuilder's bands are higher: $8,000–15,000 excl. GST for a refresh and $15,000–35,000 for a mid-range job. Both were checked on 16 September 2026. The calculator uses the small-room bands automatically when you choose a room under 5 m².
Why does a small bathroom cost almost as much as a big one?
Because the expensive parts do not shrink. A small bathroom still has a shower to waterproof, a toilet, a basin and a fan; it still needs a licensed plumber to rough in and fit off, a registered electrician for the lighting and fan, and a waterproofer whose membrane has to cure before tiling. Labour is 40–50% of a mid-range job in Superior's breakdown, and much of that is the same number of visits whatever the floor area. What does shrink is tiles and paint, which are a smaller share of the bill than people expect.
Which layout choices make a small bathroom work?
- Leave the toilet where it is. The waste pipe is the hardest thing to move, and moving a toilet or shower adds $2,000–6,000 excl. GST (CheckMyBuilder).
- Swap the bath for a shower if nobody uses it. It frees floor space and, done like for like, stays inside the consent exemptions. Our bath to walk-in shower guide covers the resale question.
- Wall-hung vanity and toilet. Seeing the floor run underneath makes a room read larger, and it is easier to clean.
- Frameless or fixed glass instead of a curtain or framed door, so the shower does not visually cut the room in half.
- A niche, not shelves. A recessed shower niche keeps bottles off the floor, but it is the hardest part to waterproof, so only with a builder who details it properly.
- Large tiles, fewer grout lines. Fewer joints is less to clean and less to crack, though the floor has to fall correctly to the waste.
- Light and air. A good extractor fan matters more in a small room, where steam has nowhere to go. In a rental it must vent outside to meet the healthy homes ventilation standard.
Can a small bathroom be a wet room?
It can, and it is a common way to make a tiny room usable: the whole floor is waterproofed and falls to one waste, with no shower tray or step. It costs more in waterproofing than a shower with a tray, because the membrane covers the whole floor and has to be detailed at the door, and it leaves less margin for error. Our waterproofing guide sets out what Building Code clause E3 requires of it.
Questions
How much does a small bathroom renovation cost in NZ?
Superior Renovations puts a small bathroom (under about 5 m²) at $4,000–8,000 for a minor upgrade, $15,000–25,000 for a full renovation and $25,000–35,000 for a custom one with layout changes. The page does not state GST status.
How long does a small bathroom renovation take?
A minor upgrade is days; a full renovation with a new membrane is usually two to three weeks on site, because the membrane has to cure before tiling and the trades come in sequence. Our timeline guide breaks it down.
Is it worth removing the bath from a small bathroom?
Often, if nobody in the house uses it. It frees floor space and a shower is cheaper to waterproof than a bath and shower combined. If the house has only one bathroom and families are the likely buyers, keeping a bath can matter more at resale.
Does renovating a small bathroom need consent?
Not usually. Relining and retiling an existing bathroom is exempt under Schedule 1 clause 12, and moving or replacing fixtures is exempt under clause 35 as long as the number of sanitary fixtures in the house does not go up and the plumbing is done by an authorised person.
Sources
Published 19 October 2026, last updated 19 October 2026 by Bathroom Renovation NZ. Every figure and rule on this page is quoted from a source we read in full on the checked date. See our editorial policy.