Bathroom Renovation Cost Calculator

Bathroom renovation is one of the costlier rooms per square metre because it combines multiple trades — plumbing, tiling, electrics, carpentry — plus expensive fittings and waterproofing requirements. Bathroom refurbishments typically run 4,000-15,000 depending on size, specification, and structural change.

Typical per-m² rangesbasic refresh (new suite, tiles, light fittings, same layout) 800-1,200/m². Mid-range renovation (new suite, walls removed, improved lighting, heated towel rail, underfloor heating) 1,200-2,000/m². Premium renovation (structural change, wet room or walk-in shower, premium fittings, bespoke cabinetry) 2,000-3,500+/m².

Plumbing and electrics are the cost drivers that surprise most homeowners. Any change to layout (moving toilet, relocating shower, adding new radiator) adds 500-2,000 depending on complexity. Waste pipe routing and ventilation are often underestimated. Get quotes including these explicitly rather than assuming they're cosmetic.

What the result means

Total is realistic all-in estimate. The per-m² figure calibrates your project against typical market rates. If significantly lower than market ranges, specification is basic; significantly higher suggests premium work or challenging property (very small, awkward layout, older property).

Budgeting tool, not a construction quote. Get multiple tradesperson quotes for firm pricing.

Quick example

With bathroom size of 5 and cost per m² of 1,500 (plus labour days of 8 and daily labour rate of 250), the result is 10,925.00. Change any figure and watch the output shift — it's often more useful to see the pattern than to memorise the formula.

Which inputs matter most

You enter Bathroom Size, Cost per m², Labour Days, Daily Labour Rate, and Contingency %. Not every input has equal weight. Adjusting one input at a time toward extreme values shows which ones move the result most.

What's happening under the hood

Sum of per-m² material costs and labour (days × rate), multiplied by contingency factor for unexpected extras. The formula is listed in full below. If the number looks off, you can retrace the calculation by hand — that's the point of showing the working.

Reading payback vs outright cost

Payback tells you when you're break-even, not whether the purchase is a good idea. A short payback on something you barely use is still a loss. Pair the number with an honest count of expected usage.

What this doesn't capture

Purchase decisions rarely come down to payback alone. Reliability, time saved, enjoyment, and alternatives outside the calculation all matter. The figure gives you the money side cleanly so you can weigh it against everything else honestly.