The calculation, without hidden assumptions
Perimeter is the distance around a shape, but the required inputs change with the geometry. Rather than forcing separate thin pages for every simple shape, this calculator keeps rectangle, square, triangle and circle perimeter work in one place and displays the formula used for the selected shape.
How to use this calculator
Choose the shape.
Enter the dimensions requested for that shape; unused fields are ignored.
Read the perimeter/circumference plus the corresponding area when the entered dimensions define one.
Where people use it
- •Border, edging and trim estimates
- •Geometry homework
- •Quick drawing checks
Example: 6 × 4 rectangle
Perimeter is 2(6+4)=20 units. The same dimensions produce an area of 24 square units.
What the result does not assume
- •A circle uses the term circumference rather than perimeter, though it represents the same “distance around” idea.
- •Irregular shapes need to be broken into measured segments or handled by a dedicated geometry model.
Frequently asked questions
Is circumference a perimeter?+
Yes in concept; circumference is the standard name for the perimeter of a circle.
Does the calculator support irregular polygons?+
Not on this page. Add measured edge lengths directly or use a polygon-specific tool when the shape matters.
Why show area too?+
Area is often the next quantity needed for material planning, and it provides a useful cross-check on the entered dimensions.
Semantic next steps
Continue the calculation
These links move to a different input, formula or project stage rather than a keyword variation of this page.
Circle Calculator — Radius, Diameter, Circumference & Area
Start with radius, diameter, circumference or area and solve the other circle measurements with the inverse formula and high-precision π value shown.
OpenTriangle Calculator — Sides, Angles, Area & Perimeter
Solve a triangle from three side lengths using Heron’s formula and the law of cosines, with validity checks, angle sum, area, perimeter and triangle-type labels.
OpenPythagorean Theorem Calculator — Solve a Leg, Hypotenuse & Area
Solve a right-triangle leg or hypotenuse from two known sides, show the substituted equation, area, perimeter and acute angles, and reject impossible side combinations.
OpenRectangle Calculator — Area, Perimeter & Diagonal
Calculate rectangle area, perimeter, diagonal, aspect ratio and optional difference between a measured diagonal and the Pythagorean theoretical value.
OpenVolume Calculator — Box, Cylinder & Sphere
Calculate volume for rectangular boxes, cylinders or spheres with shape-specific inputs, surface-area companion results and cubic-unit outputs.
OpenSlope Calculator — Rise, Run, Percent, Angle & Ratio
Convert rise and run into decimal slope, percent grade, angle, ratio and straight-line length, with negative rise supported for descending grades.
OpenSquare Footage Calculator
Calculate square footage for rectangles, circles and triangles, convert the area to square meters and estimate cost from a price per square foot.
OpenScale Calculator — Drawings, Maps and Models
Convert real measurements to scaled drawing or model sizes, convert scaled sizes back to real dimensions, or find the 1:N scale ratio.
OpenFree publisher widget
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Give readers the live calculator without rebuilding the math. Copy the responsive embed in one click, or customize width, height, border and corner radius before publishing. The branded MAXScanner attribution stays visible.
Keep the result connected to the real job
MAXScanner keeps the formula and assumptions beside the result so you can verify the number before using it in a drawing, estimate, specification, worksheet or document. Where a supplier, manufacturer, drawing or applicable standard owns a requirement, that source remains authoritative.