Inverse Sine Calculator
Find the angle whose sine is a given value, in degrees and radians.
Two angles share every sine
arcsin returns only the principal value between −90° and 90°. sin 30° and sin 150° are both 0.5, so if your problem allows an obtuse angle, the supplementary value shown above may be the one you want. Triangle problems solved with the sine rule hit this constantly.
The formula
θ = arcsin(x), defined only for −1 ≤ x ≤ 1
Every result on this page comes from this formula. Nothing is rounded until the final display, so figures match a spreadsheet to the cent.
How to use the Inverse Sine Calculator
- Fill in each field with your own figures — the defaults are only there as an example.
- The result updates as you type, so there is no button to press.
- Check the breakdown under the main result for the supporting numbers.
- Use the copy button to take the result with you, or share the link to reload the same inputs.
Inverse Sine Calculator — frequently asked questions
Is this inverse sine calculator free to use?
Yes. Every calculator on the site is free, needs no sign-up, and runs entirely in your browser, so your figures never leave your device.
How accurate is the result?
The maths is exact for the formula shown on the page. Accuracy in the real world depends on your inputs and on assumptions the formula cannot see, so treat the output as a well-grounded estimate rather than a quote.
Can I use it on my phone?
Yes. The page is responsive, weighs a few kilobytes and works offline once loaded, so it behaves the same on a phone as on a desktop.
What people search for
This page answers each of these searches. They are the exact phrases visitors use to find the inverse sine calculator.
- sin inverse calculator
About this calculator
Written and reviewed by The Samsung Calculator editorial team. Every calculator is written against a published formula, reviewed against at least one independent reference implementation, and dated when it changes.
Last reviewed August 23, 2026 · Calculation runs client-side · No data collected · Report an error