Trig Calculator - Six Functions of Any Angle

Trig calculator that evaluates sin, cos, tan, cot, sec, and csc of any angle in degrees or radians and reports quadrant, reference angle, and the reduced radian value.

Updated: June 16, 2026 • Free Tool

Trig Calculator

Type any real angle. Large and negative values are reduced into the unit-circle range automatically.

Pick the unit of the input angle. The reference angle and reduced-angle output follow this choice.

Results

Sine (sin of angle)
0
Cosine (cos of angle) 0
Tangent (tan of angle) 0
Cotangent (cot of angle) 0
Secant (sec of angle) 0
Cosecant (csc of angle) 0
Reference angle 0
Reduced angle in radians 0rad
Unit-circle quadrant 0
Period of sin and cos 0

What Is a Trig Calculator?

A trig calculator is a tool that turns one real angle into all six standard trigonometric functions at once: sin, cos, tan, cot, sec, and csc. Type an angle in degrees or radians and the result panel returns the six values with the unit-circle quadrant, reference angle, and reduced radian value, so every figure is consistent with the same input.

  • Homework and reference checks: Confirm sin, cos, tan, cot, sec, and csc for textbook reference angles like 30, 45, 60, 90, and 225 degrees without flipping through a trig table.
  • Quadrant sign verification: Type an angle in the second, third, or fourth quadrant to see which functions are positive in a single panel.
  • Undefined-value inspection: See where sin or cos equals zero so tan, sec, cot, or csc are reported as undefined instead of 0 or NaN.
  • Unit-circle intuition: Watch the reduced angle and quadrant change as the input sweeps past 90, 180, and 270 degrees to feel periodicity.

Textbook problems usually use a small group of trig functions together. Sine, cosine, and tangent carry the load for triangles, vectors, and waveforms, while cot, sec, and csc show up in identities and precalculus homework. Keeping all six in one panel makes sure the values stay consistent with the input angle.

Unit-circle context sits next to the numeric output. Quadrant and reference angle are the pieces textbooks use to explain signs, so surfacing them removes the need for a separate sketch before reading the numbers.

When the problem only needs the three primary ratios and not the reciprocal three, Sin Cosine Tangent Calculator returns a focused sin-cos-tan panel.

How the Trig Calculator Works

The form reads your angle and the unit selector, converts the input to a radian value, reduces that radian value into [0, 2*pi), and then evaluates the six standard trigonometric functions from sin and cos of the reduced angle. Cot, sec, and csc are derived from sin and cos through the standard reciprocal identities, and the reference angle and quadrant come from the reduced radian value.

sin(theta), cos(theta), tan(theta) = sin(theta)/cos(theta), cot(theta) = cos(theta)/sin(theta), sec(theta) = 1/cos(theta), csc(theta) = 1/sin(theta); theta is converted to radians and reduced into [0, 2*pi) before evaluation
  • angle: The input angle in the unit you selected above the form. The form accepts any real number.
  • unit: Degrees or radians. When degrees is selected the page multiplies the input by pi/180 to land on a radian value.
  • sin, cos: Computed after converting to radians and reducing into [0, 2*pi).
  • tan, cot, sec, csc: The four remaining trig functions, derived from sin and cos by the reciprocal identities.
  • reference angle: The acute angle between the terminal side of theta and the nearest x-axis, reported in the chosen unit.
  • quadrant: The unit-circle quadrant of the reduced angle. Boundary angles on an axis are reported as 'On axis'.

Because cot, sec, and csc are reciprocals of sin and cos, the four reciprocal rows are reported as undefined exactly where their denominators equal zero. A small tolerance keeps a mathematically pi/2 angle from returning very large values for tan and sec.

The reduced radian value is also reported so you can see which representative angle the panel is showing.

Worked example: 30 degrees (Quadrant I)

angle = 30, unit = degrees

Convert 30 degrees to radians: 30 * pi/180 = pi/6. Then sin(pi/6) = 1/2, cos(pi/6) = sqrt(3)/2, tan(pi/6) = 1/sqrt(3).

sin = 0.5, cos = 0.866025, tan = 0.577350, cot = 1.732051, sec = 1.154701, csc = 2.0, quadrant I, reference angle 30°.

30 degrees sits in quadrant I of the unit circle, so all six functions are positive and the reference angle equals the input.

Worked example: 225 degrees (Quadrant III)

angle = 225, unit = degrees

Convert 225 degrees to radians: 225 * pi/180 = 5*pi/4. Then sin(5*pi/4) = -sqrt(2)/2, cos(5*pi/4) = -sqrt(2)/2, tan(5*pi/4) = 1.

sin = -0.707107, cos = -0.707107, tan = 1, cot = 1, sec = -1.414214, csc = -1.414214, quadrant III, reference angle 45°.

In quadrant III both sin and cos are negative, so tan and cot are positive while sec and csc stay negative.

According to Wikipedia: Trigonometric functions, sin(0) = 0, cos(0) = 1, sin(pi/2) = 1, cos(pi/2) = 0, sin(pi/6) = 1/2, cos(pi/6) = sqrt(3)/2, and the six standard trig functions are sin, cos, tan, cot, sec, and csc.

When you finish with this forward panel and need to recover the angle from a tangent value, Arctan Calculator runs the inverse workflow.

Key Concepts Behind the Panel

Four ideas drive every number in the trig calculator panel: the unit circle, the reference angle, the quadrant sign rule, and the reciprocal identities.

Unit circle

The unit circle places the angle's terminal ray on a circle of radius 1 centered at the origin. The y-coordinate of the point is sin(theta) and the x-coordinate is cos(theta), so every trig function in the panel is a coordinate read off that circle.

Reference angle

The reference angle is the acute angle between the terminal side of theta and the nearest x-axis. It fixes the magnitude of the trig value; the quadrant decides the sign.

Quadrant sign rule

Quadrant I keeps every trig function positive. Quadrant II makes only sin and csc positive. Quadrant III makes only tan and cot positive. Quadrant IV makes only cos and sec positive.

Reciprocal identities

cot(theta) = cos(theta)/sin(theta), sec(theta) = 1/cos(theta), csc(theta) = 1/sin(theta). The panel computes the reciprocals directly, which is why cot and csc become undefined exactly when sin(theta) is zero.

These four ideas are what the panel leans on. The unit circle anchors the geometry, reciprocals extend the function set, the reference angle controls magnitude, and the quadrant sign rule controls sign.

For the inverse problem that takes a sine value back to an angle, Arcsin Calculator covers the closed interval from -1 to 1.

How to Use the Form

Working with the panel takes a few seconds. Pick a unit, type the angle, and read the six trig values plus the unit-circle metadata.

  1. 1 Choose the unit: Use the unit selector to pick degrees or radians. The reference angle and period labels change to match.
  2. 2 Type the angle: Enter any real number. Whole-number inputs like 30 or 0.7854 are common; the form accepts negative and very large values too.
  3. 3 Read the six functions: Look at sin, cos, tan, cot, sec, and csc in the results panel. Each row updates on every keystroke.
  4. 4 Check the quadrant and reference angle: Use the quadrant row and the reference angle row to confirm the panel is showing the representative angle inside [0, 2*pi).
  5. 5 Reset to the default: Use the Reset button to clear the form and return to 30 degrees in degree mode.

A student working through a 45-45-90 right triangle needs sin(45 degrees), cos(45 degrees), and tan(45 degrees). They leave the unit on degrees, type 45, and read sin = cos = 0.707107 and tan = 1 with quadrant I and a 45 degree reference angle.

If the angle is part of a real right triangle and you need side lengths, Right Triangle Calculator carries sin and cos through to the missing sides.

Benefits of the All-in-One Panel

Putting all six trig functions and the unit-circle metadata in one panel saves time on homework, formulas, and code reviews.

  • Six functions in one view: sin, cos, tan, cot, sec, and csc render in the same panel, so the basic three and the reciprocal three never get out of sync.
  • Reference angle and quadrant included: The reduced angle and quadrant rows turn a number into context, which is what you need when an angle lives outside the first quadrant.
  • Degree and radian unit toggle: The unit selector handles the pi/180 conversion, so the same input gives the same six values regardless of how you typed it.
  • Undefined rows make boundaries visible: tan, sec, cot, and csc show 'undefined' exactly when the denominator is zero, instead of returning a misleadingly large number.
  • Reduced radian value reported: The reduced-angle row shows which representative angle the panel is using, which is helpful when the input is negative or larger than a full rotation.

The biggest practical win is that all six values are visible at once. Reading sin, cos, and tan together is the same pattern textbooks use, and having cot, sec, and csc in the same view avoids the boilerplate of evaluating each reciprocal separately.

When the six trig values feed into a larger triangle problem, Triangle Calculator carries the angles and side lengths through one workflow.

Factors That Affect the Output

Four factors determine the six values on the panel, and limitations tell you when the result is on the edge of validity.

Unit of the input

Degrees and radians describe the same angle in different scales. The same 30 degrees is 0.5236 rad. The answer is only correct if the unit matches the value you typed.

Quadrant and sign rule

The six trig functions change sign as the angle moves through the four quadrants. Knowing the quadrant tells you which values must be positive before you read the numbers.

Reference angle

The reference angle is the acute angle between the terminal side and the nearest x-axis. A 30 degree reference inside a quadrant II angle still gives a sin of 0.5.

Periodicity of sine and cosine

Sine and cosine repeat every 2*pi radians, and tangent repeats every pi radians. Reducing the input into [0, 2*pi) is what keeps the panel reporting a quadrant that is meaningful.

  • The calculator evaluates a single angle at a time. For a right-triangle side solve, a right-triangle tool is the better pick.
  • The panel uses 6-digit display precision, so the answer rounds for readability. For very high-precision work, compute sin and cos directly from the radian value.
  • Angles are reduced into [0, 2*pi) for display, so the quadrant row always reads I, II, III, IV, or On axis.

The factor that most often surprises students is the sign of the reciprocal rows. In quadrant III tan and cot are positive because both sin and cos are negative, while sec and csc are negative.

According to Wolfram MathWorld: Sine, sine and cosine are the y- and x-coordinates of a point on the unit circle, and tan(theta) equals sin(theta)/cos(theta) wherever cos is non-zero.

According to Wolfram MathWorld: Radian, one full rotation equals 2*pi radians, which is 360 degrees, so each degree equals pi/180 radians (approximately 0.0174533).

When the angle arrives in turns, gradians, or degrees-minutes-seconds, Angle Converter reformats it to plain decimal degrees or radians before evaluation.

Trig calculator with an angle input, degrees or radians toggle, and a result panel showing sin, cos, tan, cot, sec, csc, reference angle, reduced angle, and quadrant
Trig calculator with an angle input, degrees or radians toggle, and a result panel showing sin, cos, tan, cot, sec, csc, reference angle, reduced angle, and quadrant

Frequently Asked Questions

Q: What does the trig calculator evaluate?

A: The trig calculator takes a single angle in degrees or radians and returns the six standard trigonometric functions of that angle: sin, cos, tan, cot, sec, and csc. It also reports the reduced angle, the unit-circle quadrant, the reference angle, and the period of sin and cos.

Q: How do I switch between degree and radian mode?

A: Use the unit selector at the top of the form. The panel converts degrees to radians internally and re-renders every row in the new unit, so the same angle in degrees and radians returns the same six trig values.

Q: Which trig functions are positive in each quadrant?

A: Quadrant I: all six functions are positive. Quadrant II: only sin and csc are positive. Quadrant III: only tan and cot are positive. Quadrant IV: only cos and sec are positive. The trig calculator shows the quadrant for every input.

Q: What is the reference angle of a trig function?

A: The reference angle is the acute angle between the terminal side of the input and the nearest x-axis. The reference angle controls the magnitude of the trig value; the quadrant controls the sign. The trig calculator reports the reference angle in the unit you chose.

Q: Why does the calculator show 'undefined' for some trig functions?

A: tan and sec are undefined when cos(theta) = 0, which happens at 90, 270, and 450 degrees (and at pi/2, 3*pi/2, and 5*pi/2 radians). cot and csc are undefined when sin(theta) = 0, which happens at 0, 180, and 360 degrees (and at 0, pi, and 2*pi radians). The panel shows 'undefined' for those rows.

Q: How are cot, sec, and csc related to sin, cos, and tan?

A: cot(theta) = cos(theta)/sin(theta) = 1/tan(theta), sec(theta) = 1/cos(theta), and csc(theta) = 1/sin(theta). The panel computes the reciprocals directly, which is why cot and csc become undefined exactly when sin(theta) is zero.