Trigonometry Calculator
Calculate trigonometric ratios and solve triangles from angles and sides.
How to use Trigonometry Calculator: Open Trigonometry Calculator in your browser — it loads instantly and works offline once cached. Enter your values in the input fields. Every field is labelled so you know exactly what to type. The result updates automatically as you type — there is no "submit" round-trip to a server. Everything runs inside your browser, so your data never leaves your device.
Calculate trigonometric ratios and solve triangles from angles and sides. Trigonometry Calculator is a free, browser-based tool in the Filevane math calculators collection — there is nothing to install, no account to create and no watermark on your results. It works on desktop, tablet and mobile, and because the work happens on your own device it stays fast even with large inputs.
How to use Trigonometry Calculator
- Open Trigonometry Calculator in your browser — it loads instantly and works offline once cached.
- Enter your values in the input fields. Every field is labelled so you know exactly what to type.
- The result updates automatically as you type — there is no "submit" round-trip to a server.
- Adjust any input to compare scenarios and see how the outcome changes in real time.
- Copy or note the result. Nothing you enter is stored or sent anywhere.
Why use Trigonometry Calculator?
- 100% free with no limits, no sign-up and no watermarks.
- Private by design — your data are processed in your browser and never uploaded to a server.
- Fast and lightweight, with instant results even on a phone or a slow connection.
- Works everywhere — any modern browser on Windows, macOS, Linux, Android or iOS.
- Part of a full math calculators suite, so related trigonometry tasks are one click away.
What people use Trigonometry Calculator for
- Finding a missing side or angle in a right-angled triangle for a homework problem.
- Working out a roof pitch, a ramp angle or a diagonal brace length on site.
- Converting between degrees and radians when the answer looks wrong by a factor of 57.
Trigonometry Calculator: limits and things worth knowing
- SOH-CAH-TOA applies only to right-angled triangles. For any other triangle you need the sine rule or the cosine rule, both of which are handled here.
- Inverse functions return one angle, but two angles can share a sine value. In a triangle the obtuse solution is often the intended one — check that your three angles sum to 180°.
- Degrees and radians are the single most common source of an incorrect result. Most programming languages take radians; most homework is in degrees.
- The sine rule is ambiguous when you know two sides and a non-included angle: there may be zero, one or two valid triangles.
Is it private and secure?
Your privacy is built in. Trigonometry Calculator runs completely on your device, so whatever you enter stays in your browser and is never transmitted, logged or stored on any server.
Network activity: none. Nothing is sent and nothing is fetched. This tool makes no network request at all once the page has loaded — which is why it keeps working if your connection drops.
You do not have to take that on trust — our privacy proof page publishes the Content-Security-Policy that enforces it, lists every third party it permits, and shows how to verify the whole claim yourself.
Learn more
Why Browser-Based Tools Are Safer for Your Files — Most online converters upload your files to a server. Client-side tools don't. Here's why that difference matters for privacy.
Frequently asked questions
How do I find a missing side with trigonometry?
Pick the ratio that links the side you know to the one you want: sine is opposite over hypotenuse, cosine is adjacent over hypotenuse, tangent is opposite over adjacent — the SOH-CAH-TOA mnemonic. Enter the angle and the known side and the calculator rearranges it for you.
How do I solve for an angle?
Use the inverse functions — arcsin, arccos or arctan — on the ratio of the two sides you know. If the opposite side is 3 and the hypotenuse 5, the angle is arcsin(0.6), about 36.87 degrees.
Should I work in degrees or radians?
Degrees for geometry, surveying and construction; radians for calculus and most programming languages, whose sin() and cos() expect radians. Feeding degrees to a function expecting radians is the most common silent error in trigonometric code.
Why does my calculator return an error for arcsin?
Because sine and cosine only ever produce values between -1 and 1, so arcsin(1.4) has no real solution. Getting a ratio above 1 almost always means the hypotenuse and a shorter side have been entered the wrong way round.
Can one set of measurements give two valid triangles?
Yes, and it catches people out. When you know two sides and an angle that is not between them, the law of sines can produce two valid triangles — one acute and one obtuse — because sin(x) and sin(180° − x) are equal. This is the ambiguous case. Check both candidates against the requirement that the three angles total 180°, and against whether the resulting triangle is physically sensible for your problem.
Does this work for non-right triangles?
Right-angled triangles are handled directly by the ratios above. For any other triangle you need the law of sines or the law of cosines, since SOH-CAH-TOA only holds when one angle is exactly 90 degrees.
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