Your surveying instrument displays angles in gradians (250 grad), but your blueprint is in degrees. What angle does the blueprint show?

250 × 0.9 = 225°. Record 225° on the blueprint.

I'm reading an older French survey record that lists angles in 'gon.' Is that the same as gradian?

Yes — gon, grad, and gradian are the same unit. 1 gon = 1 grad = 1/400 of a full circle. Multiply by 0.9 to get degrees. The ISO standard term is 'gon'; 'grad' is more common in practice.

My theodolite reads 166.7 gon for a deflection angle. What's that in degrees?

166.7 × 0.9 = 150.03° ≈ 150°. Rounded, this is the expected 150° deflection angle — confirming a hexagonal parcel boundary angle.

Is it better to work in gradians or degrees for surveying?

Gradians are mathematically cleaner for right-angle work and decimal arithmetic. Degrees are universally understood and compatible with more software. Use whichever your instrument is calibrated for, and convert at the data export stage.

Gradians to Degrees Converter

Enter a value to instantly convert between angle units.

From

Precision4 dp

1 Gradian = 0.9 Degree

Key Formulas

Degree → Radian

rad = ° × 0.0174533

Radian → Degree

° = rad × 57.2958

Degree → Gradian

grad = ° × 1.11111

Gradian → Degree

° = grad × 0.9

Formula

degrees = gradians × 0.9

Theodolites and total stations configured in gradian mode output angles in grad (100 grad = right angle). When a surveyor brings data from a European instrument into degree-based GIS software, CAD systems, or bearing-calculation spreadsheets, every angle needs this simple multiplication by 0.9. A traverse recorded on a gradian-mode instrument needs all its bearings converted before being entered into software that expects degrees — this conversion is done file-by-file in data post-processing.

Source: ISO 80000-3:2019 (Quantities and units — Space and time)

Last reviewed: 2026-06-11 · see our methodology

Frequently Asked Questions

Real-World Examples

A right angle on the theodolite — 100 grad converts to 90°, confirming the perpendicular leg of a traverse is correctly set out.

100 grad = 90 °

A back-bearing (opposite direction) — 200 grad = 180°, the standard check that a traverse reversal is recorded correctly.

200 grad = 180 °

A 150 grad bearing on a site instrument — 135° for the degree-based site drawing, specifying a diagonal line at 45° from the east direction.

150 grad = 135 °

A full angular circuit — 400 grad = 360°, confirming the surveying instrument's full-circle calibration before starting a traverse.

400 grad = 360 °

degrees to radians radians to degrees degrees to gradians

Gradians to Degrees Converter

Key Formulas

Formula

Frequently Asked Questions

Real-World Examples

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