Coordinate Converter

About the Coordinate Converter

Paste a coordinate in any common format and get it back in all the others, as you type. Degrees–minutes–seconds to decimal degrees, decimal to DMS, decimal minutes either way.

Unlike the two map tools on this site, this page has no map, and that is the point: with nothing to draw, nothing has to be fetched. It runs entirely in your browser and works with the internet disconnected.

The three formats, and who uses which

There is one location and several ways to write it. Software is strict about which it accepts, which is why converting is such a common chore.

Decimal degrees (DD) — 37.579617, 126.977041

One number for each direction, with a minus sign for south and west. This is the modern default: websites, apps, spreadsheets, databases and programming libraries almost all expect it.

Degrees, minutes, seconds (DMS) — 37°34'46.62"N 126°58'37.35"E

The traditional form. One degree contains 60 minutes; one minute contains 60 seconds — exactly like a clock, which is where the words come from. Paper maps, atlases, land registries and legal documents still use it.

Degrees and decimal minutes (DDM) — 37°34.777'N 126°58.622'E

Whole degrees, then minutes with a decimal part, and no seconds at all. This is the standard on marine chartplotters and aviation GPS, so it turns up constantly around boats and aircraft and almost nowhere else.

The arithmetic, if you want to do it by hand

It is simpler than it looks, and knowing it makes the mistakes easier to spot.

DMS to decimal degrees: divide the minutes by 60, divide the seconds by 3600, and add both to the degrees.

37° 34' 46.62" → 37 + 34÷60 + 46.62÷3600 → 37 + 0.566667 + 0.012950 → 37.579617

Decimal degrees to DMS: the whole number is the degrees. Multiply what is left by 60 — the whole part of that is the minutes. Multiply what is left again by 60 for the seconds.

37.579617 → 37°, then 0.579617 × 60 = 34.777, so 34', then 0.777 × 60 = 46.62"

Decimal minutes stops one step early: degrees, then the remainder × 60, kept as a decimal.

Then add the hemisphere: S and W are negative in decimal degrees, N and E positive.

How many decimal places do you actually need?

This is the question behind most coordinate conversions, and most converters never answer it. Latitude lines are evenly spaced everywhere on Earth, so each decimal place is worth a fixed distance:

2 decimals — about 1.1 km. A town.
3 decimals — about 110 m. A block.
4 decimals — about 11 m. A building.
5 decimals — about 1.1 m. A doorway.
6 decimals — about 11 cm. Finer than a phone can measure.
7 decimals — about 1 cm. Survey equipment.

Five is plenty for almost everything. A phone GPS is doing well at 3–5 m, so writing seven decimals records noise, not location. The page shows the real-world distance for whichever precision you pick.

Longitude works the same way at the equator and gets finer towards the poles — a degree of longitude is about 111 km at the equator but only 78 km at 45° latitude, and nothing at all at the pole. Quoting the latitude figure is the safe way to describe precision.

Mistakes this tool catches

Coordinates go wrong in a small number of very repeatable ways, and the converter is built to notice them.

60 minutes or 60 seconds. Neither exists. 37°60'00" should be 38°00'00". A value of 60 or more means something went wrong upstream, so it is rejected rather than quietly accepted.

A minus sign *and* a hemisphere letter. -33.86S cancels itself out and lands in the northern hemisphere. Use one or the other, never both.

The pair reversed. Latitude never exceeds 90; longitude goes to 180. If the first number is well past 90 it must be a longitude, so the pair is read the other way round — and the page tells you it did, rather than silently moving you.

Rounding 59.999 seconds. Round it naively and you get the impossible 60". Here the rounding carries properly into the next minute, and into the next degree if it needs to.

Losing the decimals. Whole degrees are not a rough position — one degree of latitude is about 111 km.

Why this page has no map

Every map you have ever seen on a web page is made of small pictures fetched from a map server, and asking for them tells that server which part of the world you are looking at.

For the two map tools on this site that trade is worth it — you cannot show a place without drawing it. Here there is nothing to draw. The conversion is a handful of multiplications, so the page does it on your device and nothing is sent anywhere. You can disconnect the internet and it keeps working.

If you do want to see the place, Coordinates to Map is one click away.

What you can do with it

Turn DMS from a document or deed into the decimal degrees your software wants
Turn decimal degrees into DMS for a form or a legal record
Convert to or from decimal minutes for a chartplotter or aviation GPS
Tidy up coordinates pasted from a phone or a word processor, curly quotes and all
Check whether a coordinate pair is reversed before importing it
Work out how precise a coordinate really is
Convert coordinates on a plane, on a boat, or with no signal at all

Features

All four formats at once, updating as you type
Reads any input format — DMS, decimal, decimal minutes, signed, hemisphere letters either side
Handles curly quotes and odd symbols that other converters choke on
Rounds correctly, so you never see an impossible 60' or 60"
Flags reversed pairs instead of silently moving the point
Shows what your precision is worth on the ground, in metres
Copy any format with one press
Fully offline — no map, no lookup, nothing sent anywhere

Good to know

Nothing here needs the internet. Load the page once and it keeps working with no connection.
This is not an address lookup. It converts between coordinate formats; it does not turn a coordinate into a street address or the reverse.
Everything uses WGS 84, the system GPS, phones and web maps share. Old survey data in a different system converts cleanly between formats here but still refers to a slightly different spot on the ground.
Latitude first. Every format on this page is written latitude then longitude, which is the convention almost everywhere outside a few mapping libraries.

Common questions

How do I convert DMS to decimal degrees?

Divide the minutes by 60, divide the seconds by 3600, then add both to the degrees. For 37 degrees 34 minutes 46.62 seconds: 37 + 34/60 + 46.62/3600 = 37.579617. Add a minus sign if the coordinate is south or west. Pasting it into the box above does all of that as you type.

How do I convert decimal degrees to DMS?

The whole number is the degrees. Multiply what is left by 60 and the whole part of that is the minutes. Multiply the remainder by 60 again for the seconds. So 37.579617 becomes 37 degrees, 34 minutes, 46.62 seconds.

What are degrees and decimal minutes, and who uses them?

Whole degrees, then minutes written with a decimal part, and no seconds at all - for example 37 degrees 34.777 minutes. It is the standard on marine chartplotters and aviation GPS, so it turns up constantly around boats and aircraft and almost nowhere else.

How many decimal places should I keep?

Five is enough for almost everything. Each decimal place of latitude is a fixed distance: two places is about 1.1 km, four is about 11 m, five is about 1.1 m, and six is about 11 cm. Seven decimals is about a centimetre, which is finer than any phone can measure.

Why does my coordinate show 60 minutes or 60 seconds?

Because something rounded badly further upstream. Neither exists: 60 minutes is the next degree and 60 seconds is the next minute. This converter rejects such values rather than accepting them silently, and its own rounding carries properly, so 59.999 seconds becomes the next minute instead of an impossible 60.

Does this work without an internet connection?

Yes. There is no map and no lookup here, only arithmetic, so nothing you type leaves your device. Load the page once and it keeps working with the connection switched off.

Related tools

GPS Coordinates — click a map to read coordinates off it
Coordinates to Map — paste coordinates and see the place
Unit Converter — lengths, weights and the rest
Image Metadata Viewer — read the coordinates stored inside a photo
Number Base Converter — binary, decimal and hexadecimal

How to use it

Paste your coordinate into the box, in whatever format you have
Read the other formats as they appear underneath
Pick the decimal places you need — the page says what each is worth on the ground
Press Copy next to whichever format you were asked for