Geodetic tool
Coordinate Transformation
Free online conversion between all Bulgarian and international coordinate systems. Supported: BGS2005 (CCS2005/Lambert and UTM 34N/35N), BGS1970 (zones K3, K5, K7, K9), BGS1950 (3° and 6° zones), BGS1930, the Sofia local system, WGS84 / ETRS89, Web Mercator and geocentric (ECEF) coordinates. Single points, decimal degrees and degrees/minutes/seconds, plus batch conversion of many points with CSV download.
⚠️ Accuracy. The tool converts using the official transformation model (grids built from 10,000 control points passed through the Bulgarian Cadastre Agency transformation engine), achieving centimetre-to-decimetre accuracy. For cadastral, legal and official purposes always verify the result against the official BGSTRANS program of the AGCC.
Which coordinate systems are supported?
- BGS2005 — the current official system (an ETRS89 realization), in the Lambert Conformal Conic projection (CCS2005) and UTM zones 34N and 35N, plus geographic coordinates.
- BGS1970 — a conformal conic projection in four zones: K3 (NW), K5 (SE), K7 (NE) and K9 (SW) Bulgaria.
- BGS1950 — Gauss–Krüger projection (3° and 6° zones) on the Krassovsky ellipsoid.
- BGS1930 and the Sofia local system — older systems found in archive materials.
- WGS84 / ETRS89, Web Mercator and geocentric (ECEF) coordinates for web maps and GNSS.
How do I convert coordinates?
Choose the input and output systems, enter the coordinates (for BGS1970 also pick the zone) and press “Convert”. For many points use the “Batch” tab — paste one point per line and download the result as CSV.