gizmobench

Latitude Longitude Converter

Paste a coordinate pair in any of the three notations and the other two appear beside it, on the first screen, with no sign-up and no map to wait for. It reads 42.3876, -71.0995 and 42°23'15.36"N 71°05'58.20"W as the same point, takes the hemisphere as a letter or as a minus sign, and accepts the pair on one line, on two, or with no comma at all when the hemisphere letters or an even run of numbers make the split plain. What it does differently is refuse rather than guess: a latitude past 90 or a longitude past 180 is turned down by range, minutes or seconds of 60 are turned down as arithmetic that belongs one unit up, and a minus sign that disagrees with an N is named as a disagreement instead of being quietly resolved. Rounding that reaches 60 is carried, so the page never prints 59' 60". You choose how many decimal places the last unit carries, up to eight, and the tool says what one step of that last digit is worth on the ground. Coordinates are read and written on WGS84, the frame phones and web maps report, and no datum shift is applied. It converts angles and does not look up a place or an address.

convertedDMS
42° 23' 15.36" N71° 05' 58.20" W
Decimal degrees
42.387600, -71.099500
Degrees and minutes
42° 23.256' N, 71° 05.970' W
Latitude
42° 23' 15.36" N
Longitude
71° 05' 58.20" W
Notation
Datum
WGS84

One degree is exactly 60 minutes and exactly 3600 seconds, so the three notations hold the same angle. The seconds are shown to 2 decimal places, a last digit worth about 30.9 cm north to south.

Read as Decimal degrees. On WGS84, 42.387600, -71.099500 is 42° 23' 15.36" N, 71° 05' 58.20" W.

  • DD 42.387600, -71.099500
  • DDM 42° 23.256' N
  • DMS 42° 23' 15.36" N

Worked cases

Each one runs through the same code the box above uses, the refusal included. Press Use to put it in the tool.

  • 42.3876, -71.0995to degrees, minutes, seconds
    42° 23' 15.36" N, 71° 05' 58.20" W
  • 42°23'15.36"N 71°05'58.20"Wto decimal degrees
    42.387600, -71.099500
  • Latitude past 9091.5
    Latitude runs from -90 to 90 degrees, and 91.5 is past the pole. Check the two values are not the other way round.
What this is exact about. Exact conversion between the three notations, with the hemisphere checked and latitude held inside 90 degrees and longitude inside 180. It converts coordinates on WGS84 and does not look up any place or address.

Common questions

How do I convert degrees, minutes and seconds to decimal degrees?
Divide the minutes by 60, divide the seconds by 3600, and add both to the degrees. 42°23'15.36"N is 42 + 23/60 + 15.36/3600, which is 42.387600. The hemisphere carries the sign: N and E stay positive, S and W go negative, so 71°05'58.20"W is -71.099500. Those divisions are exact by definition rather than measured, which is why 40°30'N is exactly 40.5 and not a value near it. Paste the pair into the box and the decimal form is one of the three that come back.
What is 40°30' north in decimal degrees?
40.5. Thirty minutes is half a degree, because a degree is exactly 60 minutes. The same pattern gives 40°15' as 40.25 and 40°45' as 40.75. Going the other way, the fractional part of a decimal degree times 60 is the minutes: 0.3876 of a degree is 23.256 minutes, and 0.256 of a minute times 60 is 15.36 seconds.
Which value comes first, the latitude or the longitude?
Latitude first is the convention this page follows, and it is what a map search box expects. Be careful with a reversed pair, because the numbers alone often cannot give it away: 42.3876, -71.0995 and -71.0995, 42.3876 are both inside the limits, so both are converted rather than corrected. Two things do settle it. A value past its limit is refused, so 120 in the first position is turned down as a latitude with the reminder to check the order. And hemisphere letters decide rather than position, so 71°05'58.2"W, 42°23'15.36"N is read as the pair it plainly is, put back latitude first, with the line under the readout saying that it did that.
How many decimal places should a coordinate have?
It depends on what the number is for, so the page lets you pick from none up to eight decimal places and prints what the last digit is worth. Six decimal degrees, the default, is a last digit of about 11.1 cm north to south. Two decimals on the seconds, the default for DMS, is about 30.9 cm, a whole second is about 30.9 m, and three decimals on the minutes, the default for degrees and decimal minutes, is about 1.9 m. Those figures use a nominal 111,320 m per degree of latitude: the real meridian degree on WGS84 runs from about 110,574 m at the equator to about 111,694 m at the pole, which is why the line says about.
Why was my coordinate refused?
The message names which of these it is, and what to do about it. Latitude runs from -90 to 90 and longitude from -180 to 180, so 91.5 is past the pole and 181 is past the line. Minutes and seconds run from 0 to 59.999, so 60 minutes is one whole degree and belongs in the degrees. A minus sign and an N disagree, and so do a minus sign and an E. N and S mark latitude while E and W mark longitude, so a letter on the wrong value is refused. An odd run of numbers with no comma and no letters can be split more than one way, so the page asks for a comma instead of guessing where the latitude ends.
Does this page look up the address or place for a coordinate?
No. It converts one angle pair between notations and nothing else: there is no lookup of an address, a city, a time zone or an elevation, and no request leaves the page. A place name typed into the box is refused with that fact rather than being searched for.
What datum are the coordinates in, and does the page convert between datums?
WGS84, and no. A GPS receiver, a phone and the usual web maps all report WGS84 degrees, and those are the numbers this page reads and writes: the value that comes in is the value that goes out, written another way. Converting to a local datum such as NAD27, OSGB36 or ED50 shifts the point by tens or hundreds of metres, and that is a different job which this page does not do and does not pretend to do.
Can I paste a pair without a comma between the two values?
Often, yes. A pair on two lines works, and so does one with two hemisphere letters, such as 42°23'15.36"N 71°05'58.20"W, because the letters say where the first coordinate ends. An even run of plain numbers is split down the middle, so 42 23 15.36 71 5 58.2 reads as two sets of three. An odd run has more than one reading, so the page asks for a comma rather than picking one.
Is what I paste kept or sent anywhere?
The conversion runs in this page, in your browser, and nothing is uploaded. The pair and the two choices are kept in this browser's own storage so the tool is still filled in when you come back, and that copy never leaves the device. The Start over button at the top of the page forgets it. There is no account and no sign-in.

Exact conversion between the three notations, with the hemisphere checked and latitude held inside 90 degrees and longitude inside 180. It converts coordinates on WGS84 and does not look up any place or address.