gon to degree – How to convert gon to °
While degrees are the most familiar way to measure angles, grads—also known as gons—are still widely used in parts of Europe, particularly in surveying, civil engineering, and geodetic mapping. If you’re working across international systems, you'll likely need to convert gon to degree to make your data match.
Here’s what each unit means, how they relate, and how to convert them step by step.
What is a gon (grad)?
A gon, also called a grad or grade, is a decimal-based angular unit that divides a full circle into 400 equal parts. That means:
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1 right angle = 100 gons
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1 straight angle = 200 gons
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1 full circle = 400 gons
The gon system was introduced during the French metric reforms to make calculations easier using base-10. While it’s not globally used like degrees or radians, it remains standard in surveying tools, land records, and infrastructure design across various European countries.
What is a degree (°)?
A degree splits a circle into 360 parts. It’s one of the oldest angle units, tracing back to Babylonian astronomy and widely used today in math, navigation, architecture, and science.
Because degrees divide neatly into many fractions (like 90°, 180°, and 60°), they’re practical in both basic geometry and complex design work.
How to convert gon to degree
Since a full circle equals 400 gons or 360 degrees, we can set up a direct ratio.
Formula
degree = gon × (360 / 400)
degree = gon × 0.9
This gives you the number of degrees equivalent to any given angle in gons.
Example: Convert 75 gons to degrees
degree = 75 × 0.9
degree = 67.5
So, 75 gons equals 67.5 degrees.
Need more quick conversions? Use the Angle Converter, or check out our full range of Conversion tools for any other unit type.
Did you know?
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The gon system was officially adopted in France in the late 1700s, along with the meter, kilogram, and other metric units.
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Modern surveying instruments in many European countries default to gons for measuring angles on construction sites.
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Theodolites and total stations often provide measurements in both degrees and gons, depending on user preference.
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Trigonometric formulas in civil engineering often use gons to maintain decimal precision in slope and elevation calculations.
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Geodetic coordinate systems can store bearing or azimuth data in gons, especially in European GIS frameworks.
Gons in the field, degrees in the classroom
If you studied geometry, you probably learned angles in degrees. But on a construction site in Germany, or during a cadastral survey in Switzerland, gons are often the standard.
Why? The decimal system makes gons easier to add, subtract, or divide when using engineering instruments or performing rapid calculations on-site. A right angle is simply 100 gons, and a quarter turn is 25—not 90, 45, or other fractions that don’t play well with decimals.
That said, most international standards and scientific references still use degrees, so converting between the two keeps your data consistent and compatible.
Simple conversion, big cross-system value
When you need to translate precision from one system to another, converting gon to degree becomes essential. Luckily, it’s a clean, linear conversion:
degree = gon × 0.9
Use it whenever you’re importing gon-based field measurements into software that requires degrees, or working across technical documents from different regions.
Try the Angle Converter for instant answers, or explore our full Conversion tools library for everything from length to temperature and beyond.