Geometry calculators give you fast, formula-driven answers for a wide range of shapes and solids. Whether you need the Circle Area Calculator, the Ellipse Circumference Calculator, the Cylinder Volume Calculator, or the Pyramid Volume Calculator, every tool here applies standard geometric formulas so students, designers, and engineers get reliable results without the manual algebra.
Browse the Popular list to see which tools other users reach for most, or switch to the Trending tab to catch what's gaining traction right now. Every calculator on this page is completely free, needs no account, and works on any phone, tablet, or desktop.
- Volume Calculator
- Area Calculator
- Perimeter Calculator
- Surface Area Calculator
- Circle Calculator
- Rectangle Calculator
- Triangle Calculator
-
Paint-by-Numbers Acrylic Paint Coverage CalculatorEstimate how much area your acrylic paint covers from mL and coverage per mL. Adjusts for multiple coats. Great for paint-by-numbers and craft projects.
-
Square Footage of Walls in a Room Calculator (Wall Area + Drywall Sheets)Calculate how many drywall sheets you need for a room. Enter length, width and wall height, pick a sheet size, add waste — get total sheets fast.
-
Right Triangle from Perimeter and Area CalculatorCalculate the height of an equilateral triangle from its side length using h = (√3/2)·a. Also returns area and perimeter instantly.
-
45-Degree Rule Rise Over Run CalculatorCalculate slope from rise over run instantly. Get the slope ratio, grade percentage, and angle of incline in degrees for any roof, ramp, or line.
-
Swimming Pool Gallons Calculator for Any Shape (Surface Area × Depth)Estimate the water volume in gallons of a kidney-shaped or irregular swimming pool from its surface area and average depth. Free and instant.
-
Net vs Gross Floor Area Calculator (Carpet to Built-up Area)Convert carpet area to built-up and super built-up area using loading and common-area factors. Free real-estate floor-area calculator.
-
Cube Surface Area CalculatorEnter a cube’s side length to instantly calculate its total surface area (A = 6s²). Quick help for geometry, homework, and simple planning.
-
Tank Volume CalculatorCalculate the volume and capacity of horizontal or vertical cylindrical tanks in cubic meters, liters, and US gallons from diameter and length.
-
Volume Conversion CalculatorConvert volume between liters, milliliters, US gallons, quarts, pints, cups, and fluid ounces instantly. Uses US customary units for liquid measures.
-
Equilateral Triangle Area CalculatorCalculate the area, perimeter, and height of an equilateral triangle from its side length. Free, unit-agnostic geometry tool with worked examples.
-
Distance Formula CalculatorCalculate the straight-line distance between two points (x₁,y₁) and (x₂,y₂) using the distance formula d = √((x₂−x₁)² + (y₂−y₁)²).
-
Base of a Triangle CalculatorFind the base of a triangle from its area and height using base = 2 × Area ÷ height. Fast, free triangle base calculator with worked example.
-
Arc Length from Degrees CalculatorCalculate the arc length of a circle from its radius and central angle in degrees. Also shows radians and full circumference instantly.
-
Annulus (Ring) Area CalculatorCalculate the area of an annulus (ring) from its outer and inner radii using A = π(R² − r²). Also shows ring width and circumferences.
-
Area of a Square CalculatorCalculate the area of a square instantly with side length using A = s². Also shows perimeter and diagonal. Free, fast, and accurate geometry tool.
-
Perimeter of a Circle CalculatorCalculate the perimeter (circumference) of a circle from its radius using P = 2πr. Also shows diameter and area. Fast, free and accurate.
-
Distance, Midpoint & Slope CalculatorFind the distance, midpoint, and slope between two points (x₁,y₁) and (x₂,y₂) on the coordinate plane. Free, instant, step-friendly results.
-
Area of a Pentagon CalculatorCalculate the area of a regular pentagon from its side length. Get area, perimeter and apothem instantly with the exact geometric formula.
-
Area of a Sector CalculatorCalculate the area of a circular sector from radius and central angle in degrees or radians. Also gives arc length. Free, instant, with formula and examples.
-
Conical Frustum Volume CalculatorCalculate the volume of a conical frustum with this Conical Frustum Volume Calculator. Input top radius, bottom radius, and height for accurate results. Ideal for geometry and engineering applications.
-
Hemisphere Volume CalculatorCalculate hemisphere volume easily with this free online tool. Input the radius to instantly determine the volume of a hemisphere. Accurate results for spherical segments.
-
Isosceles Triangle Area CalculatorCalculate the area of an isosceles triangle easily with base and height inputs. Get accurate results instantly for geometry problems and real-world applications.
-
Triangle Area Calculator Without HeightFind the area of a triangle without knowing its height. Enter the three side lengths and this Heron formula calculator returns the exact area.
-
Complete the Square to Find Circle Center & RadiusConvert the general circle equation x²+y²+Dx+Ey+F=0 to standard form. Instantly find the center (−D/2, −E/2) and radius by completing the square.
Frequently asked questions
What kinds of shapes and measurements can I calculate here?
The collection covers 2-D shapes such as circles, ellipses, rectangles, and heptagons, as well as 3-D solids including cylinders and pyramids. You can find areas, volumes, circumferences, and derived angles — useful for everything from math homework to layout planning and material estimation.
How accurate are the geometry results?
All tools use standard geometric formulas — for example, πr² for circle area and ⅓Bh for pyramid volume — tested against textbook references. Results are mathematically precise within normal floating-point limits. For safety- or construction-critical work, always verify dimensions against the governing engineering standard and have a qualified engineer review your figures.
Is there a cost or sign-up required?
No. Every calculator on CalculatorLib is free to use with no account, email address, or subscription needed. Open any tool and start calculating right away.
Does the site save or store the numbers I enter?
No. All calculations run entirely in your browser. No input data is transmitted to our servers or stored anywhere — your figures stay on your device.
How do I find the most popular geometry calculators?
The default category listing is ordered by real-world usage, so the most frequently used tools appear first. You can also open the Trending and Recently Added tabs at the top of the category page to explore what other users are discovering.
