Renovation calculators
Pick a tool below. Each one runs in your browser and shows the working behind the answer.
Paint & Surface
Work out how much paint your walls and ceilings need.
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Paint Calculator
Estimate how many gallons of paint a room needs — walls, optional ceiling, coats, and a waste allowance all included.
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Small Bathroom Paint Calculator
Estimate the paint a small bathroom needs, with the door, a window, and two coats accounted for.
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Kitchen Paint Calculator
Estimate kitchen wall paint, allowing for the cabinets and backsplash that cut the paintable area.
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Living Room Paint Calculator
Estimate paint for a larger living room with tall walls, several windows, and two coats.
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Ceiling Paint Calculator
Estimate the paint for a flat ceiling from the room's length and width, with coats and waste included.
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One Wall Paint Calculator
Estimate the paint for a single wall or accent wall from its width and height.
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Paint Calculator for Two Coats
Estimate paint when you are applying two coats — the standard for an even, durable finish.
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Interior Painting Cost Calculator
Estimate what it costs to paint a room from its floor size and a price per square foot of floor area.
Wallpaper
Plan rolls, pattern repeats, and trim allowance with confidence.
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Wallpaper Calculator
Find how many wallpaper rolls you need, with the pattern repeat and a trim allowance built in.
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One Wall Wallpaper Calculator
Estimate the wallpaper rolls for a single wall, with pattern repeat and a trim allowance.
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Bedroom Wallpaper Calculator
Estimate the wallpaper rolls a full bedroom needs, with pattern repeat and trim allowance.
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Peel and Stick Wallpaper Calculator
Estimate peel-and-stick wallpaper rolls, which often come in shorter lengths than traditional paper.
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Wallpaper Calculator for Accent Wall
Estimate the rolls for a single accent or feature wall, with pattern repeat and trim allowance.
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Wallpaper Installation Cost Calculator
Estimate what it costs to wallpaper a room from its floor size and a price per square foot, the way installers quote whole rooms.
Flooring & Tile
Estimate flooring and the waste factor for offcuts.
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Flooring Calculator
Calculate the floor area and how many boxes to buy, with a waste allowance that matches your layout.
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Vinyl Plank Flooring Calculator
Estimate boxes of vinyl plank (LVP) flooring with a layout-based waste allowance.
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Tile Flooring Waste Calculator
Turn a room's square footage into boxes of floor tile, with the waste allowance that cut tiles and breakage demand.
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Diagonal Flooring Calculator
Estimate flooring for a diagonal layout, which needs a higher waste allowance for angled cuts.
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Flooring Pack Calculator
Convert a room's area into the number of flooring packs to buy, using the coverage on the carton.
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Bathroom Tile Calculator
Estimate floor tile for a bathroom, with extra allowance for the many cuts around fixtures.
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Kitchen Tile Calculator
Estimate floor tile for a kitchen, with a waste allowance for cuts at cabinets and islands.
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Tile Installation Cost Calculator
Estimate what a tiled floor costs to install from the room size and an installed price per square foot — pick a level or enter your own.
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Hardwood Floor Installation Cost Calculator
Estimate what a hardwood floor costs to install from the room size and an installed price per square foot.
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Laminate Flooring Installation Cost Calculator
Estimate what laminate flooring costs to install from the room size and an installed price per square foot.
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Vinyl Plank Flooring Cost Calculator
Estimate what luxury vinyl plank (LVP) flooring costs to install from the room size and an installed price per square foot.
Insulation & Energy
Size insulation thickness and coverage for a target R-value.
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Insulation Calculator
Work out how much extra R-value you need, the thickness that delivers it, and the area to cover.
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Garage Insulation Calculator
Estimate the insulation thickness and material area to bring a garage up to a target R-value.
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Wall Insulation Calculator
Estimate the insulation thickness and area to bring a wall up to a target R-value.
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R Value Calculator
Calculate the R-value you get from a given thickness and the material's R per inch, including layers.
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U Value to R Value Calculator
Convert a U-value to an R-value, or an R-value to a U-value — they are reciprocals (R = 1 ÷ U).
Moisture & Ventilation
Right-size a dehumidifier and exhaust fan for healthy air.
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Dehumidifier Size Calculator
Get a sensible dehumidifier capacity range in pints per day for the size and dampness of your room.
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Room Ventilation Calculator
Find the exhaust fan airflow in CFM (and m³/h) a room needs from its size and a target air-change rate.
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Bathroom Fan CFM Calculator
Size a bathroom exhaust fan in CFM from the room volume and a target air-change rate.
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Basement Ventilation Calculator
Size basement ventilation in CFM from the space's volume and a modest air-change target.
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Garage Ventilation Calculator
Size garage ventilation in CFM to clear fumes, heat, and humidity from the space.
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Workshop Ventilation Calculator
Size workshop ventilation in CFM for general air turnover from dust and fumes.
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Laundry Room Ventilation Calculator
Size laundry room ventilation in CFM to control the humidity that washers and dryers add.
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Crawl Space Ventilation Calculator
Size crawl space ventilation in CFM from its low-height volume and a modest air-change rate.