Material quantity calculators for home projects
Every tool on this site turns a set of room measurements into a purchase quantity you can check by hand. You enter length, width, depth or area in the units you already work in, and the page returns liters, boxes, packs, bags, sheets, metric tons or bundles, together with the formula that produced the number and a worked example you can repeat on paper.
Pick the calculator that matches the material you are buying rather than the room you are standing in. A bedroom repaint starts at the paint calculator, but the same room needs the wall area calculator first if you want one clean surface figure to reuse later for wallpaper or drywall. Each page asks only for the measurements a tape measure gives you, shows the formula it applies, and prints a worked example with real numbers so you can check the arithmetic before you trust the result.
Every answer is a planning quantity rather than a supplier quote. The calculators apply a default waste allowance of ten percent on most materials, five percent on concrete and garden soil, and fifteen percent on wallpaper, and you can raise or lower that figure when the room shape, the pattern repeat or your own cutting skill justifies it. Rounding matters just as much. Any tool that counts boxes, packs, bags, sheets, panels or bundles rounds up to whole units, because no supplier sells two thirds of a pack.
The reference figures behind the formulas come from published sources, and each calculator page lists the ones it used along with the date the link was last checked. Where an exact standard exists, such as the foot to meter conversion factor, the page cites the standards body instead of a retailer. The site is prepared and maintained by Murat Yilmaz, and the full source policy sits on the methodology and sources page. If a number here disagrees with your own measurement, the corrections page explains how to report it.
Wall surfaces and finishes
These four tools start from the same measurement: the net wall area left once doors and windows are taken out. Work that figure out once and it carries straight through to liters of paint, rolls of wallpaper or sheets of drywall, so a single careful pass around the room with a tape measure can feed three separate orders without any remeasuring.
Paint Calculator
Estimate finish paint from room dimensions, openings, coats, coverage, and waste.
Wall Area Calculator
Calculate net wall surface area after subtracting doors and windows.
Wallpaper Calculator
Estimate wallpaper rolls from wall area, roll coverage, and pattern waste.
Drywall Calculator
Estimate drywall sheets for walls and ceiling with a cutting allowance.
Floors, tiles and joints
Floor coverings sell by the box or the pack and never by the exact square meter, so the practical question is how many whole units the room forces you to buy. These pages take the floor footprint, add an allowance for cuts and pattern matching, then round up. The grout page runs the other way, from joint length, width and depth to kilograms.
Structural mixes and framing
Wet mixes and lumber are quoted in units that rarely match the numbers on your sketch. Concrete is ordered by volume, mortar by the bag once the joint thickness and wall thickness are known, and sawn lumber by the board foot. Each page converts your dimensions into the unit the yard actually uses, and the lumber tool carries a price field so cost appears beside volume.
Concrete Calculator
Estimate ready-mix volume for a slab, footing, or pad including waste.
Mortar Calculator
Estimate mortar volume and premix bags from masonry volume, mortar share, and the manufacturer yield per bag.
Lumber Calculator
Estimate board feet and material cost from board dimensions and count.
Outdoor structures and roofs
Work outside adds variables that a square indoor room does not have. A pitched roof plane is longer than the footprint below it, so the roofing tool applies a pitch factor before it counts bundles. A fence run always needs one more post than it has bays. Decking and insulation are both sold in packs, so both round up after the waste allowance.
Decking Calculator
Estimate decking boards or packs from deck area and board coverage.
Fence Calculator
Estimate fence panels and posts from run length and spacing.
Roofing Material Calculator
Estimate roofing coverage from footprint, pitch, and waste.
Insulation Calculator
Estimate insulation packs from surface area and pack coverage.
Ground cover and garden beds
Loose materials are sold either by weight or by bagged volume, and the depth you intend to spread them at drives the entire order. Gravel converts area and depth into metric tons using the bulk density of the stone, while mulch and garden soil count bags of whatever size you choose. Set the depth carefully, because doubling it doubles the delivery.
Planning, units and cost
These three sit around the other seventeen rather than replacing any of them. The waste factor page applies an allowance to a quantity you already hold, the converter moves between metric and imperial using published exact factors, and the cost page totals two line items and adds a tax rate. Reach for them when a supplier quotes in units your measurements are not in.
How these numbers are produced
Each calculator runs one published formula, printed in full on its own page, over the numbers you enter. Nothing is hidden behind a rounding rule you cannot see: where a result is rounded up to whole boxes, packs, bags or bundles, the page states it and shows the unrounded figure inside the worked example. Reference values such as coverage rates, bulk densities and conversion factors are taken from standards bodies, trade associations and manufacturer documentation, and every source is listed with the date it was last checked.
This is a planning result, not a supplier quote; sellers use different pack, bag, board, roll, and bundle conventions, so confirm the exact product label and selling unit before you order.