Cosecant, Secant & Cotangent Calculator

All reciprocal ratios at once.

How it is calculated

The angle is entered in degrees and converted to radians. The tool then computes csc θ = 1 ÷ sin θ, sec θ = 1 ÷ cos θ and cot θ = cos θ ÷ sin θ, each shown to 6 decimal places as a unitless ratio. Negative angles and angles above 360° work, because the functions repeat every 360° (390° gives the same values as 30°). Only the function that is truly undefined is blanked and shown as a dash: csc and cot when sin θ is practically zero (0°, 180° and their multiples), and sec when cos θ is practically zero (90°, 270°). The other values are still given, so at 90° you get csc = 1.000000, sec = — and cot = 0.000000. An empty box gives nothing.

Worked example

Take θ = 30°. sin 30° = 0.5 and cos 30° ≈ 0.866025. Taking reciprocals: csc 30° = 1 ÷ 0.5 = 2.000000, sec 30° = 1 ÷ 0.866025 ≈ 1.154701, and cot 30° = cos ÷ sin = 0.866025 ÷ 0.5 ≈ 1.732051. The tool prints exactly these three numbers. A useful check: cot 30° is also 1 ÷ tan 30° = 1 ÷ 0.577350, which gives 1.732051 again.

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Common mistakes

  • Confusing the reciprocal with the inverse function. sec θ is 1 ÷ cos θ, whereas arccos gives an angle; 1.154701 here is a ratio, not 30°.
  • Entering radians. 1.5708 is treated as 1.5708 degrees, not as a right angle.
  • Reading a dash as an error. At 0° and 180° cosecant and cotangent are undefined, and at 90° and 270° the secant is, so the tool shows a dash for exactly those and still gives the rest.
  • Pairing the wrong function with its base. Cosecant goes with sine and secant goes with cosine, which is easy to reverse because the names look the wrong way round.
  • Expecting values between −1 and 1. Secant and cosecant are never inside that range; their size is always 1 or more, while cotangent can be any number.

About this calculator

Cosecant, secant and cotangent are the three reciprocal trigonometric functions: csc(θ) = 1/sin(θ), sec(θ) = 1/cos(θ), and cot(θ) = 1/tan(θ) = cos(θ)/sin(θ). They carry the same information as sine, cosine and tangent but flip the ratio, which makes certain formulas — especially in calculus and integration tables — much cleaner to work with, and they are undefined exactly where their base function equals zero (csc and cot at 0°/180°, sec at 90°/270°).

Electrical engineers use secant and cosecant when working with impedance and phase-angle relationships in AC circuits, while cotangent shows up constantly in optics (Brewster's angle calculations), surveying, and in identities like 1 + cot²(θ) = csc²(θ) that simplify trigonometric equations. In calculus, the derivatives and integrals of sec and csc appear frequently enough — d/dx[tan x] = sec²x, for example — that having quick reciprocal values on hand speeds up checking work by hand.

This calculator takes an angle in degrees and returns all three reciprocal ratios at once, so you don't have to compute sine, cosine and tangent separately and invert them yourself.

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