Circle calculator
For a circle’s area and circumference from radius or another supported quantity.
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Geometry calculators
Shape calculations that answer the question you actually have: the area of a room, the volume of a tank, the perimeter of a plot. Choose a mode offered by the particular tool: a circle, for example, can be entered by radius, diameter, circumference or area. Checks apply to the stated shape model. Use consistent units for input dimensions; area and volume use squared and cubed units respectively.
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All calculators Geometry calculators
Belt length calculator
Approximate open-belt length from centre distance and pulley pitch diameters.
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Geometry calculators
Annulus calculator
Area of the ring between two circles, its width and both circumferences.
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Geometry calculators
Circle calculator
Area, circumference, diameter and radius from any one of them.
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Geometry calculators
Cone calculator
Volume, slant height and surface area of a cone from radius and height.
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Geometry calculators
Cube calculator
Volume, surface area and diagonals of a cube from its edge, volume or surface area.
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Geometry calculators
Cuboid calculator
Volume, surface area and space diagonal from three edges.
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Geometry calculators
Cylinder calculator
Volume, lateral and total surface area of a cylinder from radius and height.
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Geometry calculators
Ellipse calculator
Area, approximate perimeter, eccentricity and foci of an ellipse from its semi-axes.
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Geometry calculators
Conical frustum calculator
Volume, slant height and surfaces of a truncated cone from two radii and the height.
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Geometry calculators
Parallelogram calculator
Area from a base and height, or from two sides and the angle between them.
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Geometry calculators
Polygon area from coordinates calculator
Area, perimeter and centroid of a simple polygon from ordered vertices.
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Geometry calculators
Prism calculator
Volume and surface areas of a regular prism from base side and height.
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Geometry calculators
Pyramid calculator
Volume, slant height and surface areas of a regular pyramid.
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Geometry calculators
Rectangle calculator
Area, perimeter and diagonal of a rectangle from its sides or its area.
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Geometry calculators
Regular polygon calculator
Area, perimeter, apothem and angles of a regular polygon.
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Geometry calculators
Rhombus calculator
Area, side, perimeter and height of a rhombus from its two diagonals.
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Geometry calculators
Right triangle calculator
Hypotenuse, leg, area and perimeter by the Pythagorean theorem.
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Geometry calculators
Circular sector calculator
Sector area, arc length and chord from the radius and the angle.
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Geometry calculators
Sphere calculator
Volume and surface area of a sphere from its radius, diameter or volume.
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Geometry calculators
Square calculator
Area, perimeter and diagonal of a square from any one of them.
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Geometry calculators
Trapezoid calculator
Area of a trapezoid from its two bases and height; perimeter from the legs.
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Geometry calculators
Triangle calculator
Triangle area from three sides or base and height; perimeter and classification require all three sides.
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Geometry calculators
Golden ratio calculator
Split a segment in the ratio φ, or find the partner to a given size.
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Geometry calculators New
Pyramid frustum calculator
Volume, slant height and surfaces of a square pyramid frustum.
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Geometry calculators
Slope calculator
Slope in per cent and degrees from rise and run.
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Which calculation to choose
Cylinder calculator
For cylinder volume and surface; height adds the third dimension.
What to prepare
Measure one shape in consistent units. Identify whether the known dimension is radius or diameter.
Common mistake
Diameter is twice radius. Area uses square units; volume uses cubic units.
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New calculators
FAQ
Why do I have to choose a length unit?
Use the unit stated beside the field and convert related lengths to it before entry. Area has the squared unit and volume the cubed unit. The number 5 alone cannot tell the calculator whether you meant metres or centimetres.
Why does the calculator refuse some triangles?
Three positive lengths form a non-degenerate triangle only if every pair sums to more than the third. Equality gives a degenerate zero-area figure, which this model does not accept; a smaller sum makes a triangle impossible.
Are the results rounded?
Display is rounded, and numerical arithmetic also has finite precision. Formulas may use approximations to π or trigonometric functions. Check the tool’s domain and numerical limits; arbitrarily precise symbolic answers are not promised.
Can I mix units in one calculation?
Only when the tool explicitly offers separate unit controls. Otherwise convert related dimensions to the stated unit before entering them. The form cannot detect that you entered centimetres as metres.
Categories
Finance
Loan, mortgage, compound interest, percentage and discount calculators for everyday money decisions.
Currency
Currency converter and popular pairs for quick travel, shopping and budget estimates.
Fitness
BMI, calories, running pace and one-rep max calculators for training and body metrics.
Home improvement
Tile, wallpaper, paint and laminate calculators for estimating materials before a project.
Date and time
Age and business day calculators for dates, planning and deadlines.
Maths calculators
Remainder, prime factors, proportions, equations and logarithms.
Business and marketing
Contribution margin, customer acquisition cost, average order value, returns and ad ROI.
Unit converters
Convert length, mass, temperature, pressure and other quantities between units.
Electronics calculators
Current, voltage, resistance, power and circuit supply.
Computer calculators
Download speed, bandwidth, frames, resolution and disk space.
Study calculators
Test percentages, the grade you need and reading speed.
Car calculators
Fuel consumption, power to weight, trip cost and speed.
Household calculators
Electricity use, tips and filling a pool.
Physics calculators
Force, energy, work, power and motion with stated units and models.
Chemistry calculators
Concentration, moles, dilution, pH and the ideal gas law.