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🧭 Coordinate Converters

DMS to Decimal Degrees Converter

Convert DMS coordinates to decimal degrees. Enter degrees, minutes and seconds with N/S/E/W direction.

This page explains how the dms to decimal degrees converter works, the data and formulas behind it, and how to interpret the result. Coordinate conversions are exact to machine precision; the only source of error is the precision of the input. All formats describe the same location - the notation just differs. The tool is one of 329 free, open tools on JoseFitani for maps and geography. It runs in your browser with no sign-up needed. Use the search field or click the map to drop a pin - the tool uses standard mathematical formulas for each format, all based on the WGS84 datum (EPSG:4326) and returns the result in seconds. Below you'll find a step-by-step guide, real use cases, the methodology, FAQs, and data sources.

Decimal Degrees
48.858400°, 2.294500°
Degrees Minutes Seconds
48° 51' 30.24" N, 2° 17' 40.2" E
UTM
31N 448252E 5411955.03N
MGRS
31UDQ 48252 11955
Plus Code
8FW4V75V+9R

MGRS is derived from the WGS84 ellipsoid series used on this site (accurate to a few metres) — suitable for reference and education, not for survey-grade work. Plus Codes follow the Open Location Code specification.

How to use this tool

1
Enter your input

Type your query, paste coordinates, or click on the map. The tool uses standard mathematical formulas for each format, all based on the WGS84 datum (EPSG:4326) to process your input locally in the browser.

2
View the result

The result appears instantly with the map showing your location. You can adjust by clicking elsewhere or searching a new place.

3
Copy or share

Click Copy to save to clipboard, or Share to send a direct link with the exact inputs.

What people use this tool for

Plotting positions from paper charts

Nautical charts print positions in degrees and minutes, but modern chartplotters and navigation apps expect decimal degrees. Converting each waypoint before a voyage lets the paper plan transfer accurately into the electronic navigation system.

Example: A sailor in Cornwall converts harbour waypoints from a paper chart, such as 50 degrees 09 minutes north, into decimal degrees for the boat's chartplotter.
Preparing coordinates for Google Earth

Textbooks and worksheets often give coordinates in DMS, while Google Earth and web maps accept decimal degrees in their search boxes. Converting first lets students paste positions directly and see the location instantly instead of wrestling with format errors.

Example: A teacher in Ohio converts DMS coordinates from a geography exercise so students can paste the decimal values straight into Google Earth and find the landmark.
Digitising legacy field notes

Older survey and exploration records logged positions in DMS long before decimal degrees became the digital standard. Converting those readings during digitisation brings historical datasets into modern databases without re-surveying anything.

Example: A surveyor's assistant in Perth converts DMS readings from 1980s field books into decimal degrees for the company's project database.
Feeding mapping APIs correctly

Web mapping APIs and libraries expect coordinates as decimal numbers, so any DMS values in a client brief or dataset must be converted before they can be used in code. Doing the conversion up front prevents subtle parsing bugs in the application.

Example: A developer in Berlin converts DMS waypoints from a client's tour itinerary into decimal degrees because the mapping library only accepts decimal input.

How it's calculated

Decimal degrees = degrees + (minutes / 60) + (seconds / 3600). South and West values are negative.

The calculation runs in your browser - no data is sent to our servers. Map tiles come from OpenStreetMap (ODbL license), geocoding uses Nominatim (1 request/second limit), and elevation uses the Open-Elevation API backed by SRTM data. All are free, open services.

All calculations use the WGS84 datum (EPSG:4326), the same as GPS. For other datums (NAD27, NAD83, ETRS89), a separate conversion is needed. The difference is typically under 1 metre - negligible for most uses but important for survey-grade work.

The formulas match those in professional GIS software (QGIS, ArcGIS, Global Mapper), just in a browser-friendly form. For sub-metre accuracy, use professional software with ellipsoidal calculations. Results are shown in multiple units: km and miles for distance, km²/m²/hectares/acres for area, metres and feet for elevation. Conversion factors are exact (1 mile = 1.609344 km), so the only error source is input precision.

Related tools and resources

For more tools in this category, explore the related tools listed below. Each tool includes full documentation, examples and FAQs. Explore related tools in our Coordinates category for complementary functionality. See the Tools index for all 329 tools, or read our blog for in-depth articles on geography and maps.

Frequently asked questions

Why are South/West negative?

By convention, the equator and prime meridian divide each axis into positive and negative halves.

What is the formula for converting DMS to decimal degrees?

Decimal degrees equals degrees plus minutes divided by 60 plus seconds divided by 3600. For example, 48 degrees 51 minutes 30 seconds becomes 48 + 51/60 + 30/3600, which is 48.8583 degrees. The tool applies this arithmetic for you, but knowing the formula helps you sanity-check results.

How do I handle negative coordinates, like south or west?

Keep the sign on the degrees and treat minutes and seconds as positive: -33 degrees 52 minutes 08 seconds equals -(33 + 52/60 + 8/3600), which is -33.8689. South latitudes and west longitudes are negative; north and east are positive. Never attach the minus sign to the minutes or seconds.

What if my coordinate has only degrees and minutes?

Leave seconds at zero; the formula still works with just the minutes divided by 60. Many marine and aviation positions are published this way, sometimes with decimal minutes, such as 50 degrees 09.5 minutes. Enter what you have and the conversion handles the rest.

How many decimal places should I keep in the answer?

Match the precision of your source: five decimal places represent about 1 metre, and six represent about 10 centimetres. Keeping more digits than your input justifies implies false precision. A DMS value given to whole seconds deserves at most about five decimal places out.

Why do mapping APIs want decimal degrees instead of DMS?

A single plain number is trivial to parse, store, and compute with, while DMS needs special parsing for its symbols and multiple components. Nearly every web map, GPS API, and spatial database expects decimal degrees, which is why conversion is such a common step.

Does the DMS-to-decimal conversion work offline?

Yes. Converting DMS to decimal degrees is simple arithmetic performed entirely in your browser. No server lookup or connection is involved at any point, so it works on a plane, on a boat, or anywhere else without signal.

Can seconds be larger than 60?

No. Sixty seconds make one minute, exactly as sixty minutes make one degree. If your source shows something like 75 seconds, normalise it first: 75 seconds is 1 minute 15 seconds. The tool expects properly normalised input.

What is the difference between the prime and double-prime symbols?

The prime symbol marks minutes of arc and the double-prime marks seconds of arc: 48 degrees 51' 30''. One minute equals 60 seconds, and one second equals 1/3600 of a degree. Mixing them up is the most common manual conversion error, so double-check which value sits where.

Data sources & methodology