Paste a coordinate in any common notation and get it back in every other format. Runs entirely in your browser — nothing is uploaded, and it works offline once the page has loaded.
All three notations describe the same point on Earth. Which one you meet depends entirely on which device or system produced it, and mixing them up is the single most common cause of a geofence landing in the wrong country.
| Format | Example | Where you'll see it |
|---|---|---|
| Decimal degrees (DD) | 41.402771, 2.174379 | APIs, GeoJSON, Google Maps URLs, most GPS trackers |
| Degrees, minutes, seconds (DMS) | 41° 24' 10.0" N | Paper maps, surveying, aviation charts |
| Degrees, decimal minutes (DDM) | 41° 24.1663' N | Marine GPS, NMEA sentences, handheld chartplotters |
GeoJSON stores positions as [longitude, latitude]. Almost
everything a human reads — Google Maps, GPS displays, street addresses —
writes them as latitude, longitude. Swap them and your zone jumps
somewhere else entirely. Our
GeoJSON viewer flags this
automatically: any latitude beyond ±90 is a swapped pair, because latitude
simply cannot exceed 90 degrees.
DMS notation carries the hemisphere as a letter (N/S/E/W). Decimal degrees
carry it as a minus sign. Convert 8° 30' W and forget the
W, and you get +8.5 instead of -8.5 — a point
roughly 1,900 km east of where you meant. The converter above keeps the
hemisphere attached through every conversion.
More precision than your GPS can deliver is just noise. At the equator:
| Decimal places | Precision | Useful for |
|---|---|---|
| 2 | ~1.1 km | Which town |
| 3 | ~110 m | Which neighbourhood |
| 4 | ~11 m | Which building |
| 5 | ~1.1 m | Which doorway |
| 6 | ~11 cm | Survey work |
Consumer GPS is accurate to roughly 5–10 metres in the open and much worse between buildings, so five decimal places is the practical ceiling. Anything beyond that is recording receiver noise.
A geofence is only as trustworthy as the coordinates that define it. If your boundary is drawn from a mis-parsed coordinate, every alert it produces is wrong — and you usually find out at the worst possible moment.
Once your coordinates are right, use the geofence builder to turn them into a real zone, or the distance calculator to check how far apart two points really are. If you want something to actually watch that boundary and notify you when a device crosses it, that's what Geoblip does.
This tool draws the boundary. Geoblip watches it — assign a phone or GPS tracker, set the hours it should be active, and get an email or push notification the moment it crosses the line.