FinToolSuite

Bathroom Renovation Cost Calculator

Updated April 17, 2026 · Major Purchases · Educational use only ·

Realistic bathroom renovation budget including trades and extras.

Calculate realistic bathroom renovation cost including materials, fittings, labour, plumbing, and contingency for unexpected extras.

What this tool does

Enter bathroom size, tier (basic/mid/premium), labour days, and contingency. The tool calculates full renovation cost with trades and extras.


Enter Values

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Formula Used
Area in m²
Cost per m²
Labour days
Daily labour rate
Contingency %

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Disclaimer

Results are estimates for educational purposes only. They do not constitute financial advice. Consult a qualified professional before making financial decisions.

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. Flip one at a time toward extreme values to feel which ones move the needle most for your situation.

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.

Example Scenario

A 5 m² m² bathroom renovation produces a total based on the inputs provided.

Inputs

Bathroom Size:5 m²
Cost per m²:1,500 £/m²
Labour Days:8 days
Daily Labour Rate:250 £
Contingency %:15
Expected Result£10,925.00

This example uses typical values for illustration. Adjust the inputs above to match a specific situation and see how the result changes.

Sources & Methodology

Methodology

Sum of per-m² material costs and labour (days × rate), multiplied by contingency factor for unexpected extras.

Frequently Asked Questions

Do I need to move plumbing?
If yes, add 500-2,000 depending on how far and what's being moved. Moving a toilet is harder than a sink. Structural wall changes add more. Avoid layout changes to save significant money.
What's included in cost per m²?
Typically materials (tiles, suite, fittings, plumbing parts, waste/waterproof, paint) but not labour. Labour varies by region and trades required. Check quotes carefully — some include, some don't.
How long does it take?
Small bathroom basic refresh: 5-7 days. Mid-range with minor layout change: 10-14 days. Premium with structural work: 3-5 weeks. Add time for unexpected delays.
Can I DIY some of it?
Tiling and paint often yes. Plumbing and electrics typically require certified tradesperson for compliance. DIY the non-regulated work to save 30-40% on those portions.

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