Solve any rectangle measurement quickly — find Area and Perimeter together, isolate a missing Length or Width, compute the Diagonal, or verify angles — using dedicated calculators built to handle whichever dimensions you already have.
Browse the Most Popular list to see which tools others use most, or try the Trending tab for recently active additions. Every calculator is free, sign-up-free, and runs on any phone, tablet, or desktop.
- Volume Calculator
- Area Calculator
- Perimeter Calculator
- Surface Area Calculator
- Circle Calculator
- Rectangle Calculator
- Triangle Calculator
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Rectangle Pixel Dimensions from Print Size and DPI CalculatorCalculate the pixel width and height a rectangular image needs for a given print size and DPI. Get total pixels and megapixels instantly.
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Air Volume of a Rectangular Room CalculatorCalculate the air volume of a rectangular room in cubic metres from its length, width and height. Free, instant, and great for HVAC and ventilation sizing.
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Rectangle Height from Width and Aspect RatioFind a rectangle's height from its width and aspect ratio. Enter width and ratio (e.g. 16:9) to get the proportional height instantly.
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Rectangle Print Size from Pixels and DPI CalculatorCalculate the printed width and height of a rectangular image from its pixel dimensions and DPI. Get results in inches and centimeters instantly.
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Rectangular Roof Area CalculatorCalculate the actual sloped surface area of a rectangular roof from its footprint length, width, and pitch angle. Get square feet and roofing squares.
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Rectangular Raised Garden Bed Soil CalculatorCalculate how much soil to fill a rectangular raised garden bed. Enter length, width and depth to get cubic feet, cubic yards, bags and liters.
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Fence Posts for a Rectangular Yard CalculatorEstimate how many fence posts you need for a rectangular yard. Enter length, width, and post spacing to get the total posts, corners included.
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Rectangular Tablecloth Size CalculatorCalculate the right rectangular tablecloth size from your table length, width and desired drop. Get exact cloth dimensions in inches instantly.
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Square Feet to Square Yards for a Rectangle CalculatorConvert a rectangle's dimensions in feet to square yards instantly. Enter length and width in feet to get the area in square yards (1 sq yd = 9 sq ft).
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Section Modulus of a Rectangular Beam CalculatorCalculate the elastic section modulus S = b·h²/6 of a rectangular beam cross-section, plus moment of inertia and area. Fast, accurate engineering tool.
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Rectangle Width from Height and Aspect Ratio CalculatorFind a rectangle's width from its height and aspect ratio. Enter height and a ratio like 16:9 to instantly get the matching width. Free online tool.
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Rectangular Field / Plot Area CalculatorCalculate the area of a rectangular field or plot of land from its length and width in meters, feet, or yards. Get results in m², hectares, and acres.
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Diagonal of a Rectangle CalculatorFind the diagonal of a rectangle from its length and width using d = √(l² + w²). Also shows perimeter and area instantly.
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Pavers Needed for a Rectangular Patio CalculatorCalculate how many pavers you need for a rectangular patio. Enter patio and paver dimensions plus waste to get the exact count, area, and overage.
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Decking Boards for a Rectangular Deck CalculatorCalculate how many decking boards you need for a rectangular deck based on deck size, board width, board length and the gap between boards.
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Bricks Needed for a Rectangular Wall CalculatorCalculate how many bricks you need for a rectangular wall from its length, height, brick face size and a waste allowance. Fast and free.
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Topsoil Volume for a Rectangular Bed CalculatorCalculate how much topsoil you need for a rectangular garden bed. Enter length, width and depth in metres to get the volume in cubic metres and cubic yards.
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Rectangular Prism Space Diagonal CalculatorFind the space diagonal of a rectangular prism (cuboid) from its length, width and height using d = √(l² + w² + h²). Free, instant.
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Rectangular Tank Volume in Liters CalculatorCalculate the volume of a rectangular tank in liters from its length, width, and height in centimeters. Also shows cubic cm and US gallons.
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Grass Seed for a Rectangular Lawn CalculatorCalculate how much grass seed you need for a rectangular lawn from its length, width, and seeding rate. Get the amount in grams and kilograms.
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Rectangle Square Feet to Square Meters CalculatorConvert a rectangle's dimensions in feet to area in square meters. Enter length and width to get instant ft² and m² results with the 0.092903 factor.
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Rectangle Square Meters to Square Feet CalculatorConvert a rectangle's area from square meters to square feet. Enter length and width in meters to get the total area in ft² instantly.
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Rectangular Plate Weight CalculatorCalculate the weight of a rectangular metal plate or sheet from its length, width, thickness, and material density. Get kg, grams, and pounds instantly.
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Wallpaper Rolls for a Rectangular Wall CalculatorCalculate how many wallpaper rolls you need for a rectangular wall. Enter wall and roll dimensions to get the number of rolls, rounded up.
Frequently asked questions
Which rectangle properties can I calculate?
You can solve for area, perimeter, length, width, diagonal, and angles — starting from whichever measurements you already know. Tools like the Rectangle Diagonal Calculator and Rectangle Angle Calculator handle the less obvious outputs that come up in carpentry, construction, and classroom geometry.
How accurate are the results?
Calculators use standard geometric formulas — A = l × w, d = √(l² + w²), and related expressions — with double-precision arithmetic. For safety- or construction-critical work, verify results against the governing standard and have a qualified engineer review the figures before proceeding.
Is there any cost?
No — all rectangle calculators in this collection are completely free. There is no subscription, no account required, and no features hidden behind a paywall — every result is instantly accessible to everyone.
Are the numbers I enter stored anywhere?
No. Every calculation runs locally in your browser. We do not collect, log, or transmit any values you input — your measurements stay on your device.
Which rectangle calculator is used most?
The Most Popular list is ranked by actual usage. The Rectangle Area and Perimeter Calculator typically leads, but check the Trending tab for tools that are gaining traction with other users right now.
