Lat/lng swap checker

Reversed latitude and longitude is the most common geodata bug there is. Paste coordinates or a GeoJSON file and check whether your lat/lng pairs are in the wrong order before they break your map.

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Frequently asked questions

Is GeoJSON [latitude, longitude] or [longitude, latitude]?

GeoJSON is [longitude, latitude] — longitude first. RFC 7946 requires every position to be ordered [longitude, latitude], which is the opposite of the spoken "lat, long" convention. That mismatch is the single most common source of swapped coordinates.

Why do my points show up in the ocean off West Africa?

That's the Gulf of Guinea near 0°,0° — "Null Island." It usually means either your coordinates failed to parse and defaulted to zero, or latitude and longitude are swapped so the values cancel out near the origin. Check that the first number in each position is longitude, not latitude.

How do I fix reversed coordinates?

Swap the two values in every position so the order becomes [longitude, latitude], then re-validate against RFC 7946. The swap checker flags pairs where the first value exceeds ±90° (impossible for a longitude-first latitude), and the converter can flip and reproject a whole file at once.

Can a range check always detect a swap?

No. Latitude is bounded to ±90° and longitude to ±180°, so a first value above 90° proves a swap. But when both values fall within ±90° — much of central Europe, for example — a swap is indistinguishable from correct order by range alone, so a clean result there isn't a guarantee.