How is a decimal coordinate split into degrees, minutes and seconds?

The whole-number part is the degrees. Multiply the fractional part by 60 to get minutes; the whole part of that is the minutes. Multiply the remaining fraction by 60 again to get the seconds.

What range are valid latitude and longitude values?

Latitude must be between -90 and +90 degrees and longitude between -180 and +180 degrees. Values outside these ranges are not valid geographic coordinates.

How do the sign and the hemisphere letter relate?

A positive latitude is north (N) and a negative latitude is south (S). A positive longitude is east (E) and a negative longitude is west (W). The DMS form uses the letter instead of a minus sign.

Why does my converted value have 60 seconds rounded?

Rounding seconds to whole numbers can occasionally produce 60. This tool keeps a few decimal places of seconds to avoid that and to preserve precision; round only at display time if needed.

What is the Lat/Lng to DMS Converter?

Convert decimal latitude and longitude into DMS (degrees, minutes, seconds) notation with N/S/E/W hemisphere letters. Enter signed decimal coordinates and get the exact sexagesimal form used on maps, GPS units and nautical charts. It runs free in your browser on Gera Tools, with nothing uploaded.

Lat/Lng to DMS Converter

Name: Lat/Lng to DMS Converter
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

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This tool converts decimal latitude and longitude into DMS — degrees, minutes and seconds — the sexagesimal notation still used on nautical charts, aviation maps and many GPS receivers. Enter a signed decimal coordinate such as 51.507351, -0.127758 and get back 51°30'26.5" N, 0°7'39.9" W.

How it works

A decimal degree value is split into three parts. Take the absolute value of the coordinate, then:

degrees = floor(value)
minutes = floor((value - degrees) * 60)
seconds = (((value - degrees) * 60) - minutes) * 60

The original sign decides the hemisphere letter: positive latitude is N, negative is S; positive longitude is E, negative is W. Because there are 60 minutes in a degree and 60 seconds in a minute, the conversion is exact — only display rounding introduces any error.

Practical examples

London’s Trafalgar Square sits at approximately 51.507351, -0.127758 in decimal degrees. Converting:

Latitude: 51° 30’ 26.5” N
Longitude: 0° 7’ 39.9” W

The negative sign on longitude becomes the W hemisphere suffix; the negative sign on latitude would become S.

Classic pitfall — rounding to whole seconds: If you only need whole seconds, note that rounding seconds = 59.97 to 60 is mathematically wrong — you should carry it forward as 1'00". This tool keeps two decimal places of seconds to avoid that and lets you round only at display time.

When DMS is required versus decimal

Context	Preferred format
Nautical charts	DMS or DDM
Aviation (ICAO)	DMS
Google Maps URL	Decimal
GIS / PostGIS	Decimal
Printed topo maps	DMS
GPS receivers (many models)	Both, user-selectable

DDM (decimal minutes) is a related hybrid format — degrees as whole numbers, minutes with decimals — used by many marine GPS units. This tool outputs full DMS, not DDM. To convert DDM, treat the decimal-minute portion: minutes are the integer part and seconds are the fractional part times 60.

Precision notes

One second of latitude is roughly 31 metres; one tenth of a second is about 3 metres. For cadastral or survey-grade work, keep at least two decimal places on the seconds. For a casual map label, rounding to whole seconds is fine.

The conversion is purely arithmetic and runs entirely in your browser — no coordinates are transmitted anywhere. To reverse the operation, use the DMS to Decimal converter.