Latitude and Longitude Converter

Three ways to write latitude and longitude

Decimal degrees (DD) write each coordinate as one number: 40.7128, −74.0060. Degrees, minutes and seconds (DMS) split a degree into 60 minutes and a minute into 60 seconds: 40°42'46.08"N. Degrees and decimal minutes (DDM), common on marine charts and handheld GPS units, keep the minutes as a decimal: 40°42.7680'N. All three are the same point. Google’s help pages show its search box accepting each of them — “41.40338, 2.17403”, “41°24'12.2"N 2°10'26.5"E” and “41 24.2028, 2 10.4418”.

Rounding has to carry. 40.05° is exactly 40°03'00", but a converter that rounds the seconds on their own can print 40°02'60" — a value that doesn’t exist. This one rounds the whole value in hundredths of a second first, so 59.996" becomes the next minute.

Two slips come up again and again on mapping forums. One is applying a minus sign to the degrees only: in a GIS Stack Exchange question, −122°40'04.08" came out as −121.33, because −122 + 40/60 + 4.08/3600 adds the minutes in the wrong direction. The sign belongs to the whole value — 122.6678, then negative — which this converter does. The other is typing degrees and decimal minutes as if they were decimal degrees. A geocacher on Reddit entered “N 61 06.733 E010 28.004” as 61.06733, 10.28004 and landed “several kilometers off to the West and South”; the right reading is 61.11222, 10.46673. Paste the coordinate as written and the converter works out which format it is.

Signs, hemispheres and which number comes first

Latitude runs from −90 at the South Pole to 90 at the North Pole; longitude from −180 to 180, negative west of Greenwich. A minus sign and a hemisphere letter mean the same thing, so S 33.8688 and −33.8688 are the same latitude — but not both at once, which this page refuses rather than guessing. Dropping the W from a western longitude moves the point to the other side of the world.

Maps and most notations put latitude first; Google’s help says “Enter the latitude coordinate first before the longitude coordinate.” Data formats often do the opposite. GeoJSON (RFC 7946) says the first two elements “are longitude and latitude, or easting and northing, precisely in that order”, and anything written as x, y is longitude first too. If a pasted pair has a first number above 90, it can’t be a latitude, so this converter reads it as longitude, latitude and tells you it did. The confusion is old and common: “Does Y mean latitude and X mean longitude in every GIS software?” is one of the most-viewed questions on GIS Stack Exchange, with over 550,000 views.

How many decimal places do GPS coordinates need?

One degree of latitude is about 111 km, so each decimal place is a tenth of the last. Longitude degrees shrink towards the poles — 1° of longitude is 111.3 km at the equator, 78.8 km at 45° and 55.8 km at 60° on the WGS 84 ellipsoid. The converter’s precision card shows the distances for the latitude you enter.

The GeoJSON standard puts it the same way: “6 decimal places … amounts to about 10 centimeters.” That is already finer than the reading it came from — GPS.gov says “GPS-enabled smartphones are typically accurate to within a 4.9 m (16 ft.) radius under open sky”, and worse near buildings and trees. In DMS, one second of latitude is about 31 m and 0.01" about 30 cm. As one r/gis reply put it, “Whenever you see 16 digits… somebody is using 64-bit floating point” — the digits come from the computer, not the GPS.

UTM to lat long, and back

The Universal Transverse Mercator grid gives a position in metres: a zone, an easting and a northing, such as 18T 583959 E 4507351 N for 40.7128, −74.0060. In the words of the US National Geospatial-Intelligence Agency (NGA), “UTM grid zones extend 3° in longitude in each direction from the central meridian to form 60 UTM grid zones, each 6° wide… Zone 1 extends from 180°W to 174°W.” Each zone puts 500,000 m of easting on its central meridian, so eastings stay positive; northings start at 0 at the equator in the north and at 10,000,000 m at the equator in the south. The scale factor on the central meridian is 0.9996 exactly, and NGA notes that within a zone “the variation from ground distance may be as much as 1 part in 1,000.”

UTM covers 80°S to 84°N; NGA’s standard says the polar caps use the Universal Polar Stereographic (UPS) grid instead. Two areas break the 6° rule: “Zone 32 has been widened to 9° (at the expense of zone 31) between latitudes 56° N and 64° N” for southern Norway, and around Svalbard, between 72°N and 84°N, zones 32, 34 and 36 don’t exist and 31, 33, 35 and 37 are widened. The converter applies both.

The letter after the zone is the trap. Some tools write a hemisphere, 18N or 18S. Others write the latitude band: “twenty latitude bands are lettered C through X, omitting I and O,” each 8° tall except X. Bands C to M are south of the equator and N to X north — so band S, 32°–40°N, is in the northern hemisphere, and “13S” can mean two places on opposite sides of the equator. When someone on r/gis was handed “NAD27 UTM Zone 11S”, the replies were “S designates a band of latitude rather than the hemisphere” and “Ask them for an example coordinate.” Leave the letter off altogether and an easting and northing “could be in 120 different places in the world (60 zones x N/S)”, as another reply noted. In the UTM tab, typing a letter in the zone box means a band; to give a hemisphere, leave the letter off and choose it. A pasted “S” is read as band S when the northing fits 32°–40°N, and the page says so.

The maths here is Karney’s 6th-order series for the transverse Mercator projection, which his 2011 paper shows has errors “less than 5 nm within 3900 km of the central meridian” — far beyond the edge of any UTM zone.

MGRS

The Military Grid Reference System writes a UTM position with letters for the 100 km square: 18T WL 83959 07350 is the same point as above. It reads as zone and band (18T), a two-letter 100 km square (WL), then equal numbers of easting and northing digits — five each for 1 m, four for 10 m, down to one for 10 km. NGA’s rule is that shorter references are made “not by rounding values… but by truncation”, so an MGRS reference names the south-west corner of a square, not its centre; converting one back gives that corner. For zones below 10, NGA says software should accept both 5NAB123123 and 05NAB123123 but write only the second, which this page does. “Converting MGRS to Lat/Lon or UTM” has over 41,000 views on GIS Stack Exchange, and an r/excel user asked how to turn a pasted list of MGRS references into latitude and longitude for Google Earth — which is what the List tab does.

Eastings and northings in Great Britain

Ordnance Survey maps use the British National Grid: an easting and northing in metres from a false origin that OS places “400 km west and 100 km north of the ‘true origin’ on the central meridian at 49N 2W”, or a grid reference with two letters for the 100 km square — TQ 30080 80960 is easting 530080, northing 180960, in central London. The grid sits on a different datum, OSGB36, so changing between it and GPS latitude and longitude needs a datum transformation as well as a projection.

This page uses Ordnance Survey’s published seven-parameter Helmert transformation, and is checked against OS’s own worked example. OS is clear about its limits: “The error is up to 3.5 metres (95%) both horizontally and vertically,” and “Do not use it for points outside Britain.” For survey work, OS calls OSTN15 “the definitive OSGB36/ETRS89 transformation”, good to about 0.1 m. Ireland and Northern Ireland use their own grids (the Irish Grid and Irish Transverse Mercator), which this converter doesn’t cover.

Datums: WGS 84, NAD83 and NAD27

A latitude and longitude only mean something with a datum. GPS uses WGS 84, which NGA defines with a semi-major axis of 6,378,137 m and flattening 1/298.257223563; its current realization, WGS 84 (G2296), has been in NGA’s GPS orbit and clock products since 7 January 2024. Ordnance Survey warns that “different systems of latitude and longitude in common use today can disagree on the coordinates of a point by more than 200 metres.”

• NAD83, the official datum in the United States, differs from WGS 84 by about two to four metres: NOAA says NAD 83 “is misaligned to the earth’s center by about 2.2 meters.”
• NAD27, on older US maps, is much further off: an NGS article on its NADCON tool says positions change “between 10-100 meters in the conterminous United States” and more than 200 m in Alaska and Puerto Rico.
• OSGB36, under the British grid: handled here by the Helmert step above.

This converter treats every latitude and longitude as WGS 84. It changes notation and projection, not US datums; for NAD83 or NAD27 use NOAA’s NCAT tool. NOAA is preparing new reference frames to replace NAD83, but its own pages say the current system “will remain the official NSRS” until a formal vote and transition, and its beta tools are open for testing “until at least March 2027.”

State plane coordinates

The US State Plane Coordinate System splits each state into one or more zones, each with its own Lambert conformal conic or transverse Mercator projection (oblique Mercator in one Alaska zone); NOAA describes SPCS 83 as 125 zones. Coordinates are on NAD83, in metres or feet, and you need the zone to convert them. This page doesn’t convert state plane: NOAA’s NCAT does, between state plane, UTM, US National Grid and latitude/longitude on NAD83 or NAD27, and takes files of points — the answer to a GIS Stack Exchange question, with 45,000 views, from someone with “1000's of data point” in North Central Texas zone 4202 who found “online calculators convert one entry at a time.” In another, Ohio North coordinates converted in code ended up “somewhere in Hudson Bay”: the feet had been taken as metres and x and y swapped. One unit detail matters: NIST and NOAA deprecated the US survey foot after 31 December 2022, but say NGS “will continue to support the U.S. survey foot for components of the NSRS where it is used now” — so check which foot your state plane coordinates use; the two differ by 2 parts per million. The direction trips surveyors up too. A US survey foot (1200/3937 m) is slightly longer than an international foot (0.3048 m), so, as an r/Surveying reply put it, “If your coordinates are in US feet, the numbers will get larger when you convert them to international feet.” At a state plane easting of 2,000,000 ft the change is about 4 ft.

x and y coordinates to lat long

“x, y” only converts if you know the coordinate system. Web maps use Web Mercator (EPSG:3857), the x/y tab here: metres east and north on a sphere the size of the WGS 84 equator, reaching ±20,037,508 m at ±180° and cut off at ±85.05112878° latitude. The EPSG registry calls it “Not a recognised geodetic system” that gives “errors of 0.7 percent in scale” — fine for showing a map, not for measuring. x/y from a CAD drawing, a survey or a GIS file may instead be UTM, state plane, a national grid or a local site grid; look for the EPSG code or projection in the file’s metadata before converting. If there is none, the numbers alone won’t say — “You can’t determine the projection… just from the coordinates,” as a GIS Stack Exchange answer puts it, and the most-voted answer to “Identifying Coordinate System of Shapefile when Unknown” (79,000 views) is to test guesses against data you trust. For a CAD drawing delivered with no coordinate system, the consensus in a 35-comment r/gis thread was to send it back and ask.

Address to lat long

Turning an address into coordinates (geocoding) needs a database of addresses, so it always means sending the address to a service. This page doesn’t do that: its Address tab opens your search on OpenStreetMap or Google Maps only when you click. To copy coordinates from Google Maps on a computer, right-click the place — the latitude and longitude are at the top of the pop-up; on Android, touch and hold an unlabelled spot to drop a pin. For many US addresses at once, the US Census Bureau’s geocoder accepts a batch of up to 10,000, and warns that “Coordinate results are interpolated” along the street, not measured at the door. OpenStreetMap’s free Nominatim service allows “an absolute maximum of 1 request per second” and discourages bulk geocoding. Volume is where people get stuck: an r/excel user reverse-geocoding 800,000 rows found that methods “work for 50 or 100 rows” but freeze beyond 1,000, and an r/gis user was quoted about $60 in credits for 15,000 points on a commercial platform. On phones, posts on r/GoogleMaps from 2024 to 2026 complain that coordinates have become harder to find in the app; the desktop right-click still shows them.

Lat long to decimal in Excel or Google Sheets

For degrees, minutes, seconds and hemisphere in separate cells B2:E2 — with either a minus sign on the degrees or a letter — decimal degrees are:

=(ABS(B2)+C2/60+D2/3600)*IF(OR(B2<0,E2="S",E2="W"),-1,1)

For text such as 40°42'46.08"N or −122°40'4.08" in A2, with straight ' and " marks:

=(ABS(LEFT(A2,FIND("°",A2)-1))+MID(A2,FIND("°",A2)+1,FIND("'",A2)-FIND("°",A2)-1)/60+MID(A2,FIND("'",A2)+1,FIND("""",A2)-FIND("'",A2)-1)/3600)*IF(OR(LEFT(A2)="-",RIGHT(A2)="S",RIGHT(A2)="W"),-1,1)

And decimal longitude in A2 back to DMS, rounding the seconds before splitting so they never show 60 (use "S" and "N" for latitude):

=INT(ROUND(ABS(A2)*3600,2)/3600)&"°"&INT(MOD(ROUND(ABS(A2)*3600,2),3600)/60)&"'"&TEXT(MOD(ROUND(ABS(A2)*3600,2),60),"0.00")&""""&IF(A2<0,"W","E")

We tested all three in LibreOffice Calc (Excel and Google Sheets use the same functions): they give 40.7128, −122.6678 (not −121.33) and 74°0'21.60"W, and 10.99999999 becomes 11°0'0.00" rather than 10°59'60". With zero degrees, a minus sign in a number cell is lost (−0 is 0), so for 0°07'39"W put W in the hemisphere cell; the formula gives −0.1275. Two slips in popular spreadsheet tutorials are subtracting minutes and seconds from a western longitude typed as a positive number (74°00'23"W is −74.0064, not 73.9936) and searching for curly quotes that a typed coordinate doesn’t have. For many rows at once, paste the column into the List tab here and download the CSV.