Math and conversions calculators
Maths, geometry and unit conversion calculators for everyday and technical work.
Related calculators
- Annulus Area Calculator — Enter the outer and inner radii. The calculator returns A = π·(R² − r²).
- Area Calculator — Pick a 2D shape — circle, square, rectangle, triangle, trapezium, parallelogram, ellipse, regular polygon, rhombus, sector, annulus or kite
- Capsule Surface Area Calculator — Enter the radius and the straight middle length. The calculator returns 4πr² for the two rounded ends plus 2πrh for the cylindrical side.
- Circle Area Calculator — Enter the radius. The calculator returns A = πr², the area of the flat disc.
- Circular Sector Area Calculator — Enter the radius and the angle in degrees. The calculator returns the sector's area: A = ½·r²·θ (with θ converted to radians).
- Cone Surface Area Calculator — Enter the base radius and height. The calculator splits the answer into the base (πr²) and the lateral surface (πr·s), where s = √(r²+h²) is
- Conical Frustum Surface Area Calculator — Enter the top radius, bottom radius and height. The calculator returns lateral area π(r₁+r₂)·s plus the two end discs.
- Cube Surface Area Calculator — Enter the cube's edge length and choose any output unit. The calculator returns 6a², the total area of all six faces.
- Cylindrical Tank Surface Area Calculator — Enter the base radius and height. The calculator returns SA = 2πr² + 2πrh and shows the ends and side separately.
- Ellipse Area Calculator — Enter the two semi-axes (half each diameter). The calculator returns A = π·a·b.
- Ellipsoid Surface Area Calculator — Enter the three semi-axis lengths. The calculator uses the Knud Thomsen approximation with p = 1.6075 — the standard go-to formula for gener
- Hemisphere Surface Area Calculator — Enter the radius. The calculator returns 3πr² and shows the curved and base parts separately so you can use whichever you need.
- Hexagonal Prism Surface Area Calculator — Enter the hexagon's edge length and the prism length. The calculator returns the two hexagonal ends plus the six rectangular sides.
- Kite Area Calculator — Enter the two diagonals (the long axis and the short cross axis). The calculator returns A = ½·p·q.
- Parallelogram Area Calculator — Enter the base and the perpendicular height (not the slanted side). The calculator returns A = b × h.
- Rectangle Area Calculator — Enter length and width. The calculator returns A = l × w in your chosen unit.
- Rectangular Prism (Cuboid) Surface Area Calculator — Enter length, width and height. The calculator returns SA = 2(lw + lh + wh) — the sum of all six faces.
- Regular Octahedron Surface Area Calculator — Enter the edge length. The calculator returns SA = 2√3·a², the total area of the eight equilateral triangles.
- Regular Polygon Area Calculator — Enter the number of sides (n ≥ 3) and the side length. The calculator returns the area for that regular n-gon.
- Regular Tetrahedron Surface Area Calculator — Enter the edge length. The calculator returns √3·a², the total area of the four equilateral triangle faces.
- Rhombus Area Calculator — Enter the two diagonals (p and q). The calculator returns A = ½·p·q.
- Sphere Surface Area Calculator — Enter the radius of the sphere and pick your output unit (m², ft², in², cm² and more). The calculator returns the full surface area along wi
- Spherical Cap Surface Area Calculator — Enter any two of base radius (r), ball radius (R) or cap height (h). The third is derived from r² = h(2R − h). Output: SA = 2πRh + πr² (curv
- Square Area Calculator — Enter the side length. The calculator returns A = a².
- Square Pyramid Surface Area Calculator — Enter the base edge length and the vertical height. The calculator returns the base area (a²) plus the four triangular faces.
- Surface Area Calculator — Pick a shape, enter the dimensions in your preferred units (mm, cm, m, in, ft, yd, etc.), and instantly see the surface area in m², ft², in²
- Torus Surface Area Calculator — Enter the major radius (centre to tube-centre) and the minor radius (tube cross-section). The calculator returns SA = 4π²·R·r.
- Trapezium Area Calculator — Enter the lengths of the two parallel sides and the perpendicular height between them. The calculator returns A = ½·(a + b)·h.
- Trapezoidal Prism Surface Area Calculator — Enter the trapezium dimensions (top, bottom, height, both slanted sides) and the prism length. The calculator returns the two trapezium ends
- Triangle Area Calculator — Enter the base and perpendicular height. The calculator returns A = ½·b·h. (For triangles given by three sides, use the Triangular Prism cal
- Triangular Prism Surface Area Calculator — Enter the three sides of the triangle and the length of the prism. The calculator validates the triangle inequality and returns the full sur
Related guides
- Surface Area Formulas for Common 3D Shapes — A clear, plain-English guide to surface area formulas for sphere, cube, cone, cylinder, rectangular tank, capsule, spherical cap, conical frustum, ellipsoid and