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Coordinate Converter: Decimal, DMS, UTM, MGRS, Plus Codes, Geohash

Paste a location in any common format and this converter recognises it and shows it in all the others: decimal degrees, degrees-minutes-seconds, UTM, MGRS, Plus Codes (Open Location Code), geohash and Maidenhead. Conversions use the WGS 84 ellipsoid and the high-order Krüger series, accurate to under a millimetre, and follow the NGA rules for UTM zones and MGRS truncation. Paste many lines for a CSV. Everything runs in your browser; nothing is sent unless you open the map or a pivot link.

Enter converts · Shift+Enter adds a line · latitude first unless you mark hemispheres (2°17′E 48°51′N works) · prefix geohash:, mgrs:, utm:, olc: or mh: to force a format · all maths runs in your browser.

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Which coordinate format am I looking at?

  • Two signed numbers (48.8584, 2.2945) are decimal degrees, latitude first. Numbers with °, ′, ″ or N/S/E/W are DMS or degrees-decimal-minutes; the converter accepts the hemisphere letter before or after, symbols or plain spaces, and longitude-first input when the letters make it clear.
  • A zone number and letter followed by two big numbers (31U 448252 5411955) is UTM. “N” and “S” are also latitude bands, so 33S … is read as band S per NGA practice and the note shows the southern-hemisphere reading; write 33 south … to be explicit.
  • A zone, band, two letters and an even run of digits (31UDQ4825211954) is MGRS.
  • Letters from 23456789CFGHJMPQRVWX with a “+” (8FW4V75V+9R) is a Plus Code; fewer than eight characters before the “+” means a short code.
  • Two letters A–R, two digits, then optional letter/digit pairs (JN18du) is a Maidenhead locator; lowercase base32 without a, i, l, o (u09tunq) is a geohash.

Not sure the auto-detection picked right? Choose the format from the menu, or prefix the line (geohash:, mgrs:…). Map links from Google Maps, OpenStreetMap, Bing and Apple, and geo: URIs, are read too — the same parser rules as Geolocation OSINT.

Formats at a glance

FormatEiffel Tower examplePrecisionNotes
Decimal degrees48.8584, 2.29456 decimals ≈ 0.1 mWGS 84; S and W are negative
Degrees, minutes, seconds (DMS)48°51′30.24″N 2°17′40.20″E0.01″ ≈ 0.3 many symbol style; hemisphere letters before or after
Degrees, decimal minutes (DDM)48°51.5040′N 2°17.6700′E0.0001′ ≈ 0.2 mcommon on GPS units and aviation charts
UTM31U 448252 5411955metres (shown to 1 m)zone + latitude band, or “31 North …”; 80°S–84°N NGA.STND.0037_2.0.0_GRIDS, Universal Grids and Grid Reference Systems (28 Feb 2014)
MGRS31U DQ 48252 119541 m to 100 km, truncatedNGA AA lettering scheme for WGS 84 NGA.STND.0037_2.0.0_GRIDS, Universal Grids and Grid Reference Systems (28 Feb 2014)
Plus Code (Open Location Code)8FW4V75V+9R10 digits ≈ 13.9 × 13.9 m at the equatorshort form V75V+9R needs a reference point Open Location Code specification (google/open-location-code, fetched 8 Oct 2026)
Geohashu09tunquc9 characters ≈ 4.8 × 4.8 m at the equatorbase32 alphabet without a, i, l, o Wikipedia: Geohash (fetched 8 Oct 2026)
Maidenhead locatorJN18du6 characters = 5′ × 2.5′amateur-radio grid squares Wikipedia: Maidenhead Locator System (fetched 8 Oct 2026)

How are UTM and MGRS calculated?

UTM divides the world between 80°S and 84°N into 60 zones, each 6° of longitude wide, and 20 latitude bands lettered C to X (without I and O), 8° tall except band X, which runs to 84°N. Between 56°N and 64°N zone 32 is widened to cover 3°E–12°E for southern Norway, and between 72°N and 84°N zones 32, 34 and 36 are dropped while 31, 33, 35 and 37 are widened around Svalbard; beyond 84°N and 80°S the polar UPS grid applies NGA.STND.0037_2.0.0_GRIDS, Universal Grids and Grid Reference Systems (28 Feb 2014). This converter implements those rules but not UPS.

Within a zone, latitude and longitude are projected with the transverse Mercator projection (scale 0.9996 on the central meridian, false easting 500,000 m, false northing 10,000,000 m in the south). The code uses Krüger’s series extended to sixth order in the flattening, the method Karney showed is accurate to within 5 nanometres up to 3,900 km from the central meridian C. F. F. Karney, “Transverse Mercator with an accuracy of a few nanometers”, J. Geodesy (2011), with Newton iteration for the inverse.

MGRS replaces the leading digits of the easting and northing with a 100 km square letter pair. The NGA standard specifies that references are truncated, not rounded, and identify the south-west corner of the square, from 18SUU (100 km) down to 18SUU8362601432 (1 m); its worked example turns easting 647,000 / northing 3,791,000 in zone 45S into 45SXT4791 NGA.STND.0037_2.0.0_GRIDS, Universal Grids and Grid Reference Systems (28 Feb 2014). When you paste an MGRS reference, this tool reports the centre of the square and its size.

How do Plus Codes, geohashes and Maidenhead work?

Plus Codes use a 20-character alphabet, 23456789CFGHJMPQRVWX, chosen to avoid spelling words. The first ten digits are latitude/longitude pairs in base 20; a 10-digit code covers 1/8000° by 1/8000°, about 13.9 × 13.9 m at the equator, and each extra digit splits that cell into a 4 × 5 grid (an 11-digit code is about 3.4 × 2.7 m). A “+” always follows the eighth digit, so MQPX+9G is recognisably short; it can be recovered from any reference point within roughly 40–50 km, which is how the spec’s Nairobi example 6GCRMQPX+9G shortens to MQPX+9G Open Location Code specification (google/open-location-code, fetched 8 Oct 2026).

Geohash interleaves longitude and latitude bits and writes them in a 32-character alphabet of the digits and lowercase letters except a, i, l and o; each character narrows the cell; in the article’s worked example, ezs42 decodes to a latitude of about 42.605 Wikipedia: Geohash (fetched 8 Oct 2026). Maidenhead locators, used by radio amateurs, alternate letter and digit pairs: a field of 20° × 10°, a square of 2° × 1°, a subsquare of 5′ × 2.5′ and an extended square of 30″ × 15″ — W1AW in Newington, Connecticut is FN31pr Wikipedia: Maidenhead Locator System (fetched 8 Oct 2026).

How accurate is it, and how was it tested?

The page’s engine file (coord-engine.js) was run in Node.js against independent references on 8 October 2026:

  • UTM: 1,000 random points spread evenly by area between 80°S and 84°N, plus 23 edge cases (zone and band boundaries, Norway, Svalbard, the equator, the antimeridian), compared with PROJ 9.8 through pyproj. Largest difference: 0.00001 mm. Decimal → UTM → decimal round trips agreed to 1×10⁻¹³°.
  • MGRS: all 1,023 points matched the 1 m references produced by NGA’s GEOTRANS code (via the Python mgrs package) character for character; decoding 204 references back agreed to 0.001 mm; MGRS 1 m round trips stayed within 1.4 m (the diagonal of a 1 m square). The NGA worked example 45SXT4791 is reproduced exactly.
  • Plus Codes: every case in the official test data passes — 302 encodings, 420 decodings, the validity table and 19 shorten/recover cases Open Location Code test_data CSVs (fetched 8 Oct 2026) — and every random point lies inside its decoded 10-digit cell.
  • Geohash / Maidenhead: the Wikipedia examples ezs42, u4pruydqqvj (57.64911, 10.40744) and FN31pr match, and every random point lies inside its decoded cell.
  • Parser: 31 hand-written inputs in different notations decode correctly, and 9 invalid or hostile strings (an HTML injection string, out-of-range values, mixed-up hemispheres, a short Plus Code without a reference) are rejected with a message. The page was also tested in headless Chromium at 1280 px and 375 px.

All conversions assume WGS 84. Coordinates read off an old paper map may use a different datum (for example ED50 or NAD27) and can be off by tens to hundreds of metres; this tool does not shift datums.

Where does my location go?

Nowhere, unless you click something that says otherwise. Conversions are arithmetic in your browser. Show on map downloads Leaflet 1.9.4 from cdnjs (pinned, integrity-checked) and map tiles from tile.openstreetmap.org, which reveals the area shown to those servers. Pivot links open other sites in a new tab with the coordinates in the address. The page address updates with #q= so you can bookmark or share a conversion; share it only with people who may see the location.

Next steps: open the point in Geolocation OSINT for satellite, street-level and webcam links, check the weather at that place and time with Weather Chronolocation. The geolocation OSINT guide explains the workflow.

Sources

Frequently asked questions

How do I convert decimal degrees to degrees, minutes and seconds?

Keep the whole degrees, multiply the remaining fraction by 60 to get minutes, and multiply the fraction of a minute by 60 again to get seconds; negative latitudes are South and negative longitudes West. For example 48.8584, 2.2945 becomes 48°51′30.24″N 2°17′40.20″E. Paste either form here and the converter shows both, plus degrees and decimal minutes.

What is the difference between UTM and MGRS?

They describe the same grid. UTM gives a zone number, a latitude band or hemisphere, and an easting and northing in metres, such as 31U 448252 5411955. MGRS, the military and search-and-rescue form defined by the US National Geospatial-Intelligence Agency, replaces the leading digits with two letters for the 100 km square, such as 31U DQ 48252 11954, and lets you drop digits to state a coarser precision.

Why does the MGRS reference not match the rounded UTM numbers?

Because MGRS truncates instead of rounding. The NGA standard says a grid reference identifies the south-west corner of its square and that precision is reduced by truncation, not rounding. An easting of 448252.9 m is 448253 in rounded UTM but 48252 in a 1 m MGRS reference. This tool follows that rule and, when decoding an MGRS reference, places the point at the centre of its square.

How do I decode a short Plus Code such as MQPX+9G?

A short code drops the leading digits and needs a nearby reference location to recover them. Type the reference coordinates in the Reference box, or after the code, and the converter finds the nearest matching full code, as the Open Location Code specification describes: within roughly 40 to 50 km it is unambiguous. Place names like “Nairobi” are not geocoded here, because that would send your query to a server.

How precise are Plus Codes, geohashes and Maidenhead locators?

They describe areas, not points. A 10-digit Plus Code covers 1/8000 of a degree each way, about 13.9 by 13.9 metres at the equator, and an 11-digit code about 3.4 by 2.7 metres. A 9-character geohash is roughly 4.8 by 4.8 metres at the equator. A 6-character Maidenhead locator is 5 minutes of longitude by 2.5 minutes of latitude, several kilometres. The converter decodes each to the centre of its cell and states the cell size.

Does it handle the Norway and Svalbard UTM zone exceptions?

Yes. Between 56°N and 64°N, zone 32 is widened to cover 3°E to 12°E, and between 72°N and 84°N zones 32, 34 and 36 do not exist while 31, 33, 35 and 37 are widened, exactly as tables 7 and 8 of NGA.STND.0037 specify. UTM and MGRS stop at 80°S and 84°N; the polar UPS grid is not supported, and the tool says so.

Can I convert a whole list of coordinates at once?

Yes. Paste one coordinate per line in any mix of formats and the converter switches to batch mode, showing a table of detected format, latitude, longitude, UTM, MGRS, Plus Code and geohash for every line, with errors marked. Download it as CSV or copy it. Batch mode handles up to 2,000 lines and everything stays in your browser.

Is my location sent anywhere?

No. Every conversion is JavaScript arithmetic in your browser. Only two optional actions contact other servers, and only when you click them: “Show on map” loads the Leaflet library and OpenStreetMap tiles for the area shown, and the pivot links open the site you choose in a new tab with the coordinates in its address.