Degrees and Radians
Definitions and how to convert one to the other.

Angle Converter
Converts degrees, radians, revs, grads, mils, seconds and minutes.

Right Triangle Calculator
Solves for any right triangle if you know one angle and the length of any side.
Right Triangle Calculator
Solves for any right triangle if you know two sides.

Ultimate Triangle Calculator
This solves for ANY type of triangle as long as you know all 3 sides, 2 sides and an
included angle or 2 angles and an included side. (It calculates area too.)
Knowing all 3 angles, it will calculate the relative lengths of all 3 sides.
Click here for the special case of sidesideangle.

30 60 90 and 45 45 90 Triangles
Calculator for these 2 types of special right triangles.

Angular Size Calculator
Accurate for angles up to 180 degrees.

Trigonometry Calculator
Calculates all 6 trigonometry functions and all 6 arcfunctions.
If you need to know the cosecant of 1.37 radians, this is the calculator for you.

Slope and Grade Calculator
Trigonometry in the real world. Explains and calculates how to determine a road grade, the pitch of a roof, etc.

Trigonometric Identities Tables of identities such as sin² (θ) + cos² (θ) = 1 sin (θ) = cos (90° θ) tan (θ) = sin (θ) ÷ cos (θ) and so on.

Trigonometry Tutorial
A brief review of the basics of trigonometry.
Trigonometry Tutorial Part 2
Solving Oblique Triangles by Using the Law of Sines and Cosines
Trigonometry Tutorial Part 3
Solving Oblique Triangles Without Using the Law of Sines and Cosines
Parts 2 and 3 explain solving triangles when you know all 3 sides; 2 sides and an included angle; 2 sides and a nonincluded angle; 2 angles and an included side
Part 3 explains how to calculate all 3 altitudes (heights) and all 3 angles of a triangle when you know all 3 sides.
Solving a Triangle Knowing All 3 Angles
Explains calculating the relative lengths of the sides.

Quadrants
A graphic showing all 4 quadrants and which of the 6 trigonometric functions are either positive or negative in each quadrant.

Types of Triangles
A chart showing triangles classified by angles
(acute, right, obtuse) and by sides (equilateral, isosceles, scalene).
Also has triangle area formulas and a triangle area calculator.
