DMS to Decimal Degrees Converter
Convert degrees, minutes, seconds (DMS) to decimal degrees — and back — instantly. Free, runs entirely in your browser, no sign-up.
DMS → Decimal Degrees
Decimal Degrees → DMS
Basically: paste in coordinates that look like 40°45'28.8"N and get back a clean 40.7580 you can drop straight into Google Maps, a spreadsheet, or an API call — and vice versa. Everything runs right here in your browser, so nothing gets uploaded and it works offline too.
Handy when you've copied coordinates off a paper map, a GPS unit, or an old survey and need them in the plain decimal format that code and mapping tools actually want.
How to Convert Latitude and Longitude to Decimal Degrees
Coordinates in degrees, minutes, seconds (DMS) — like 40°45'28.8"N — are split into three parts. To turn them into a single decimal degrees (DD) value used by APIs, spreadsheets and mapping libraries, use this formula:
Then apply the sign: a coordinate is negative if it is South (latitude) or West (longitude).
Worked example
- 40°45'28.8"N → 40 + 45/60 + 28.8/3600 = 40.7580
- 73°59'7.8"W → −(73 + 59/60 + 7.8/3600) = −73.9855
Decimal Degrees to DMS
Going the other way: keep the whole number as the degrees, multiply the leftover fraction by 60 for the minutes, then multiply that leftover by 60 again for the seconds.
Which Latitude / Longitude Format Should I Use?
It depends on where the coordinate is going:
- Decimal degrees (40.7580, −73.9855) — the default for geocoding APIs, GeoJSON, databases, JavaScript maps and CSV files. Latitude first.
- DMS (40°45′28.8″N, 73°59′7.8″W) — used on paper maps, marine and aviation charts, and consumer GPS displays.
- Decimal minutes (40°45.48′N) — common in marine navigation and dive computers.
Precision rule of thumb in decimal degrees: 5 places ≈ 1.1 m, 6 places ≈ 11 cm, 7 places ≈ 1 cm.
Frequently Asked Questions
How do I convert DMS to decimal degrees?
Divide the minutes by 60 and the seconds by 3600, then add them to the whole degrees: decimal = degrees + minutes/60 + seconds/3600. Make the result negative for South latitudes or West longitudes. For example, 40°45'28.8"N = 40 + 45/60 + 28.8/3600 = 40.7580.
How do I convert decimal degrees to DMS?
Take the whole number as degrees. Multiply the remaining fraction by 60 to get minutes, then multiply that fraction by 60 again to get seconds. For 40.7580: degrees = 40, minutes = 0.7580 × 60 = 45.48 → 45, seconds = 0.48 × 60 = 28.8.
What is the difference between decimal degrees and DMS?
Both describe the same location. Decimal degrees (DD) writes a coordinate as a single signed number like 40.7580, -73.9855 — the format used by most APIs, databases and mapping libraries. Degrees-minutes-seconds (DMS) splits it into 40°45'28.8"N, 73°59'7.8"W — the format printed on paper maps, GPS units and nautical charts.
What is the correct latitude and longitude format?
For software and geocoding APIs, use decimal degrees with 5–7 places after the point (about 1–10 cm of precision) and latitude first: 40.758000, -73.985500. Positive latitude is North, negative is South; positive longitude is East, negative is West.
How many decimal places do I need?
5 decimal places locate a point to about 1.1 metres, 6 places to about 0.11 metres, and 7 places to about 1 cm. For most mapping and delivery use cases, 5 or 6 decimal places is plenty.
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