Renovation Material Calculator

📖 Introduction

Enter the length, width and height of a room, the number of doors and windows and your tile size, and you get the net wall area, litres of paint, kilograms of putty, number of tiles and metres of skirting. Working it out before you buy saves a trip to the builder's merchant and avoids the hassle of returning a pallet of surplus tiles.

Anyone buying materials themselves who wants a quantity before ordering. Anyone who has hired a contractor and wants to sanity-check the amounts they quoted. And anyone building a budget: add up the rooms and you have a figure that beats guessing.

Anyone buying materials themselves who wants a quantity before ordering. Anyone who has hired a contractor and wants to sanity-check the amounts they quoted. And anyone building a budget: add up the rooms and you have a figure that beats guessing.

• Paint comes out as a decimal. Buy whole tins, round up, and keep the rest for touch-ups.
• How much waste should I allow? Five percent covers a standard straight layout. Allow ten percent or more for diagonal or patterned work.
• Why is there no cement or mortar? Only main materials are estimated. Work out consumables separately.
• Do I have to paint the ceiling? It is included by default. Untick the option if not.

The net wall area is the figure most people want, because it already has the door and window openings taken out. Treat it as the basis for any quote you collect, so that different contractors are pricing the same quantity. Ceiling area equals floor area in a rectangular room, which is why it is offered as a simple tick box rather than a separate measurement. Tile counts are rounded up to whole pieces, and boxes are estimated from a standard coverage per box, so the box figure is the least precise number here. When you order, tell the supplier your layout style, because diagonal and patterned work consumes noticeably more material than a straight grid.

✨ Features

• Area breakdown: perimeter, gross wall area, openings deducted, net wall area and ceiling, each listed separately so you can check the arithmetic.
• Paint estimate: enter the number of coats and the coverage rate, and the total litres follow from net walls plus ceiling.
• Putty: estimated at 1.5 kg per square metre, shown alongside the paint.
• Tiles: four common sizes, 300, 600, 800 and 1200 mm, rounded up to whole pieces after waste, then converted to boxes.
• Adjustable waste: 5 percent by default, raise it for diagonal layouts or patterns.
• Export: download the list as CSV to send to a contractor or keep for price comparison.

🚀 How to Use

1. Enter length, width and ceiling height, all in metres.
2. Enter the number of doors and windows plus the window width, used to deduct openings.
3. Set the number of coats and the coverage rate. Standard emulsion is roughly 10 square metres per litre.
4. Pick a tile size and adjust the waste percentage if needed.
5. Click Calculate. The full list appears on the right and can be exported.

⚠️ Notes

• Estimate onlyThese are estimates. Doors are deducted at 0.9 by 2.1 metres and windows at sixty percent of the width squared.
• Check the paint labelCoverage varies a lot with paint type and substrate. Trust the figure printed on the tin.
• Verify waste on siteDiagonal layouts, patterns and large-format wall tiles can waste far more than five percent. Check on site before ordering.
• No labor or suppliesLabour and consumables such as cement, mortar and adhesive are not included.
• Buy whole cansPaint comes out as a decimal. Buy whole tins, round up, and keep the rest for touch-ups.