Coordinate Converter
Convert latitude and longitude between decimal degrees, DMS, and decimal minutes.
By The OmniBoxKit Time Tools Team Last updated
Coordinate Converter
Accepts decimal degrees, degrees/minutes/seconds, or degrees/decimal minutes. Use a minus sign or a hemisphere letter for south and west.
- Decimal degrees DD
- Degrees, minutes, seconds DMS
- Degrees, decimal minutes DDM
What is a Coordinate Converter
A coordinate converter rewrites a latitude and longitude from one notation into another. The point on the ground never moves — only the way the numbers are written changes.
Three notations are in common use, and they all describe the same place:
Decimal degrees (DD) writes 40.446195. Degrees, minutes, seconds (DMS) writes 40°26'46.3"N. Degrees and decimal minutes (DDM) writes 40°26.772'N. Mapping software usually wants DD, printed charts and land surveys use DMS, and marine and aviation systems prefer DDM.
How It Works
Type or paste a latitude and a longitude into the two fields. The tool accepts all three notations, so you do not pick an input format — it detects what you gave it and shows the other two immediately.
Use either a minus sign or a hemisphere letter for the southern and western halves of the globe: -33.8688 and 33.8688 S mean the same thing. Symbols are optional, so 40 26 46.3 works as well as 40°26'46.3".
Each result row has a copy button. If a field cannot be read, an inline message explains why and the results stay hidden rather than showing a half-converted pair.
Which Format to Use Where
Which notation you need depends on the system you are feeding, not on where you are. Consumer mapping tools and almost every programming library expect plain decimal degrees. Nautical and aeronautical charts kept degrees and decimal minutes because a minute of latitude is one nautical mile, which makes distance estimates easy. Land records and older survey documents stay with degrees, minutes, and seconds.
When you are working across regions, pair this with a tool that can convert a time between zones so a site's location and its local time line up.
| Notation | Example | Commonly Used By |
|---|---|---|
| Decimal degrees (DD) | 40.446195, -79.982195 | Web maps, GPS apps, most software libraries |
| Degrees, minutes, seconds (DMS) | 40°26'46.3"N, 79°58'55.9"W | Land surveys, property deeds, printed atlases |
| Degrees, decimal minutes (DDM) | 40°26.772'N, 79°58.932'W | Marine navigation, aviation, handheld GPS units |
Use Cases
The usual reason to convert is that two systems disagree. You copy a coordinate out of a chart written in DMS and the mapping API you are calling only accepts decimal degrees.
Surveyors and GIS analysts move between deed descriptions and spatial databases. Sailors and pilots translate chart coordinates into the DDM their plotters expect. Developers normalise scraped or user-submitted coordinates into one canonical format before storing them, much as they would convert Unix timestamps into readable dates before saving.
Tips & Common Mistakes
The most common mistake is swapping latitude and longitude. Latitude runs from -90 to 90 and comes first in nearly every convention; longitude runs from -180 to 180. If a point lands in the wrong ocean, try the two values the other way around.
The second is dropping the sign. Omitting the minus on a western longitude moves the point to the far side of the planet. Keep the hemisphere letter if you are unsure.
Also watch precision: six decimal places in DD is about 11 centimetres, so rounding to two places can move a point by more than a kilometre. To watch several places at once, use the world clock dashboard.
FAQ
How do I convert DMS to decimal degrees?
Divide the minutes by 60 and the seconds by 3600, then add both to the degrees. For 40°26'46.3"N that is 40 + 26/60 + 46.3/3600, which gives 40.446195. Paste the DMS value into the field above and the tool does it for you.
How do I convert decimal degrees back to DMS?
The whole number is the degrees. Multiply the remainder by 60 to get minutes, then multiply that remainder by 60 again for seconds. Entering a decimal value above shows the DMS and decimal-minute forms at the same time.
Do I use a minus sign or a hemisphere letter?
Either one. A negative latitude and a latitude marked S mean the same thing, as do a negative longitude and one marked W. The tool accepts both conventions, and it will tell you if you put N or S on a longitude.
What is the difference between DDM and DMS?
DMS splits the fraction of a degree into whole minutes plus seconds. DDM stops at minutes and keeps the fraction as a decimal, so 40°26'46.3" becomes 40°26.772'. Marine and aviation systems generally use DDM.
How many decimal places do I need?
Six decimal places in decimal degrees is roughly 11 centimetres, which is more than enough for mapping. Five places is about a metre, and four is about 11 metres. Two places is only accurate to a kilometre.
Does this tool send my coordinates anywhere?
No. The conversion runs entirely in your browser using plain arithmetic, so nothing you type is uploaded, stored, or logged. It also keeps working offline once the page has loaded.