Angle converter

Angular Unit Converter: Gons, DMS, Decimal Degrees & Radians

Manually converting angles is tedious and highly prone to keystroke errors. That is why we built the Angular Unit Converter at sitemath.net. It is a dedicated, 4-way conversion engine designed specifically for the heavy lifting of spatial data geometry.

The 4-Way Angular Conversion Engine

Our calculator doesn’t just do simple A-to-B conversions. It is a live, interconnected engine. Type a value into any of the four fields, and the other three will calculate instantly with high-precision decimal accuracy.

• Decimal Degrees (DD): The universal standard for GIS platforms (like QGIS and ArcGIS), Google Earth, and most standard CAD programs. It represents an angle as a single decimal number (e.g., 154.5125°).
• Degrees, Minutes, Seconds (DMS): The traditional format used on historical survey plans and legal cadastral documents.
• Gons / Gradians: The preferred angular unit for modern European surveying and the default setting on many Trimble and Leica instruments. Instead of a 360-degree circle, a full circle is divided into 400 Gons, making a right angle exactly 100 Gons.
• Radians: The mathematical standard. If you are writing a custom Python script for point clouds or trying to use the SIN() and COS() functions in Microsoft Excel, your angles must be converted to Radians first.

Surveyor-Friendly DMS Formatting (HP Notation)

Standard online calculators force you to use clunky symbols like °, ', and " to input DMS. If you are a surveyor sitting at a numpad trying to process 100 traverse angles, typing those symbols is a massive waste of time.

We built this tool using the industry-standard HP Notation (Decimal DMS). You simply enter your angle as DDD.MMSS. For example, if your angle is 154° 30′ 45″, you simply type 154.3045 into the DMS box. The math engine automatically reads the breakdown and perfectly converts it into DD, Gons, and Radians.

Bulk CSV Angle Conversion

Converting a single angle is easy, but what if you have a CSV file with 500 total station observations recorded in Gons, and you need them in Decimal Degrees to import into a local drafting package?

Instead of writing a complex Excel macro, you can use our Bulk List Conversion tool:

1. Select Your Input Type: Tell the engine what unit your raw data is currently in (e.g., Gons).
2. Paste Your Column: Copy your single column of raw angles directly from Excel or your datalogger and paste it into the text box.
3. Convert: Hit the button, and the engine will instantly process the entire list, stripping out any blank rows or invalid text.
4. Export: Review the data in the visual table, then click Download CSV Results to get a clean spreadsheet containing all 500 angles perfectly translated into DD, DMS, Gons, and Radians.

Stop fighting with complex spreadsheet formulas and manual calculator inputs. Paste your angles into the converter and get back to processing your spatial data.