Geocalculator
Distance
CoordTrans
Units
Depth
MagDec
Tides
Meteo
Waves
Ocean
Point 1
Latitude
C
Longitude
C
Saved location
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Point 2
Latitude
C
Longitude
C
Saved location
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Format
Units
Route
Calculate distance
Distance
—
Point 1 → Point 2, ellipsoidal geodesic (Vincenty, WGS84)
Coordinates
Latitude
C
Longitude
C
UTM zone
N
S
Easting
C
Northing
C
Easting (m)
C
Northing (m)
C
Coordinate system
WGS84
UTM
ED50TM0
Saved location
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WGS84 dd.dd
WGS84 dd mm.mm
WGS84 dd mm ss.ss
UTM
ED50TM0
Route
Format
Unit converter
In
Out
Reverse
Coordinates
Latitude
Longitude
Saved location
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Format
Route
Calculate depth
Depth
—
GEBCO_2026 grid · nearest cell
Coordinates
Latitude
Longitude
Saved location
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Compass
N
E
S
W
Magnetic north
Format
Route
Calculate magnetic declination
Declination
—
NOAA WMM · negative = West, positive = East
Coordinates
Latitude
Longitude
Model
TPXO10
NOC CS3
NOC CS20
Parameter
Level
Current
Polpred API key
Saved location
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Start
End
Unit
Metric
Imperial
Datum
MSL
LAT
Series
Help
Tidal levels explained
×
TPXO10
TPXO is a family of global barotropic tidal models developed at Oregon State University (OSU). 8 primary harmonic constituents (via ODB's Open Tide API) run through a 19-year astronomical simulation, computed directly in your browser. No key needed.
NOC CS3 / NOC CS20
Product from the National Oceanography Centre. CS3 is their broader NW Europe model; CS20 is a higher-resolution model for specific licensed areas - which one(s) you have access to depends on your key. Both models provide level and depth-averaged current prediction. This choice only affects the Series plot below, not the statistics above - NOC's statistics function always picks its own model, regardless of which one you select here. Requires an API key, entered above (defaults to NOC's public demo key, which only covers a small area of the Bristol Channel/Celtic Sea and is CS20-only; your own key is stored only in this browser).
HAT — Highest Astronomical Tide
The highest level the tide is predicted to reach under average meteorological conditions, for any combination of astronomical conditions.
MHWS — Mean High Water Springs
The average height of the high waters occurring at spring tides (when the Sun and Moon's tidal effects reinforce each other).
MHWN — Mean High Water Neaps
The average height of the high waters occurring at neap tides (when the Sun and Moon's tidal effects partly cancel).
MSL — Mean Sea Level
The average level of the sea surface. All other levels here are expressed relative to this (MSL = 0).
MLWN — Mean Low Water Neaps
The average height of the low waters occurring at neap tides.
MLWS — Mean Low Water Springs
The average height of the low waters occurring at spring tides.
LAT — Lowest Astronomical Tide
The lowest level the tide is predicted to reach under average meteorological conditions, for any combination of astronomical conditions.
Tide type
The form number F = (K1+O1)/(M2+S2), a ratio of the main diurnal to semi-diurnal constituent amplitudes. F ≤ 0.25 is semi-diurnal (two similar high/low tides a day); 0.25–1.5 is mixed, mainly semi-diurnal; 1.5–3.0 is mixed, mainly diurnal; above 3.0 is diurnal (one high/low tide a day).
Parameter: Level / Current
Level shows the 8 tidal heights above. Current shows the same point's tidal current instead - a single depth-averaged value (not a 3D profile), from the same NOC data already fetched for Level, just previously unused. TPXO doesn't provide current data in this app, so Current requires NOC CS3 or NOC CS20.
Max speed / Min speed
The strongest and weakest current speed predicted over a tidal cycle.
Dir @ max / Dir @ min
The current's direction (degrees, clockwise from true North) at the moments of maximum and minimum speed.
Eccentricity
How elliptical the current's path is over a tidal cycle, from 0 (perfectly circular, e.g. far offshore where the current rotates through all directions) to 1 (perfectly back-and-forth/rectilinear, typical in a narrow channel).
Datum (Series only)
Which vertical reference the plotted height curve is measured against: MSL (default, 0 = mean sea level, same as the statistics above) or LAT (0 = Lowest Astronomical Tide, so the curve never goes negative). Only affects the Level curve on the Series plot - has no effect on the statistics above (which are always MSL-referenced by definition) or on Parameter=Current (current speed/direction don't depend on a height reference). Works for both TPXO and NOC CS3/CS20; for TPXO this runs its 19-year simulation a second time to find the LAT offset, so switching to LAT is noticeably slower than MSL.
Unit
Metric (default: m, m/s) or Imperial (ft, kt) - converts both the statistics above and the Series plot, for whichever quantity is currently shown (heights or current speed). Direction and Eccentricity are unaffected either way. Switching Unit re-displays the last result immediately, without needing to press Calculate again.
Collecting statistics
After a Calculate, drag any of the readout lines above out past the edge of the panel to drop the whole set of statistics into a small card captioned with its location and model. Each drag adds another card - they lay out in rows and columns beside the calculator, so several locations/models can be compared at once; every card has its own Clear and Export (.xlsx, with location/model as columns).
Format
Route
Calculate
TPXO10 (via ODB Open Tide API) · 8 primary constituents, 19-year harmonic simulation · all levels relative to MSL
Coordinates
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Latitude
Longitude
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Period & parameter
Help
Start
End
Season
Source
Parameter
Meteo sources explained
×
ERA5
ECMWF's global atmospheric reanalysis, served via Open-Meteo's historical archive (1940–present, hourly, ~9–31 km resolution). Covers air temperature, humidity, air pressure, wind and cloud cover.
NORA3
MET Norway's regional atmospheric hindcast (1959–present, hourly, ~3 km resolution, Lambert conformal grid over Northern Europe waters). Adds wind speed at multiple heights (10–750 m) alongside temperature, humidity, pressure, cloud fraction and precipitation.
NCEI Obs
NOAA's Global Historical Climatology Network (GHCN-Daily) – real observed daily readings from actual weather stations worldwide, not a model. Automatically finds and uses the nearest station that records the selected parameter, so coverage and period of record vary by location.
IEM Obs
Iowa Environmental Mesonet's archive of real ASOS/AWOS airport weather station reports, worldwide, at routine METAR reporting frequency (~hourly, typically :50 past the hour – special/high-frequency reports are excluded so resolution stays consistent everywhere). Covers temperature, precipitation, cloud cover/base height, wind speed/gust and relative humidity/pressure – variables that GHCN's climate-network stations rarely carry – using the nearest airport station to the selected point. Precipitation and peak gust are reliably reported mainly at US stations.
Met Office Obs
37 long-running UK stations from the Met Office's historic station data archive, monthly, back to as early as 1853 – the longest record here by far, though narrower (max/min temperature, air frost days, rainfall, sunshine) and UK-only. Pick a station directly from the Saved Location dropdown, which lists these 37 stations by name while this Source is selected. Routed through a third-party CORS proxy since the Met Office's own files don't support direct browser access – occasional failures are possible if that proxy is unavailable.
Format
Route
Calculate
Air temperature 2 m
Min
—
Average
—
Max
—
Open-Meteo historical (ERA5)
Coordinates
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Paste
Latitude
Longitude
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Period & parameter
Help
Start
End
Season
Model
Parameter
Wave models explained
×
ERA5
ECMWF's ERA5-Ocean wave reanalysis, served via Open-Meteo's historical marine archive (1940–present, global). The app reads Open-Meteo's daily maximum Hs and period values (not an hourly series), so Hs here is the highest single day in the period, not a period average. No wind-sea/swell breakdown.
NORA3
MET Norway's regional wave hindcast (1959–present, hourly, ~3 km resolution, rotated-pole grid over Northern Europe waters). Hs, Hmax, mean wave periods and wave direction, split into wind-sea and swell.
AMM15
UK Met Office regional wave reanalysis (1980–present, 3-hourly, ~1.5 km resolution, North West Shelf/Atlantic Margin: Ireland, North Sea, English Channel, Bay of Biscay), also run with WAVEWATCH III. Splits swell into two separate partitions (Hs_Swell1/Hs_Swell2) rather than one combined swell field.
Format
Route
Calculate
Waves
Hs
—
m
Hmax
—
m
Tmean
—
s
—
—
—
—
Open-Meteo historical (ERA5)
Coordinates
Copy
Paste
Latitude
Longitude
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Period & parameter
Help
Start
End
Season
Model
Parameter
3D
Ocean models explained
×
GLORYS12V1
Copernicus Marine's GLORYS12V1 global reanalysis (1993–present, 1/12° resolution, 50 depth levels) for depth-resolved temperature, salinity and currents, plus dedicated satellite-based sea surface temperature (1982–2024) and sea surface salinity (1993–2024) products. Daily-mean values.
NWS MFC
Copernicus Marine's North West Shelf regional reanalysis (NWSHELF_MULTIYEAR_PHY_004_009, 1993–present, 7 km resolution, 24 depth levels) covering the North Sea, Irish Sea and English Channel — the same depth-resolved temperature/salinity/current fields as GLORYS12V1, but at higher regional resolution. No dedicated SST/SSS or sea-ice fields. Daily-mean values.
NORA3
MET Norway's NORA3 atmospheric hindcast (1959–present) only carries one ocean-relevant field: sea surface temperature, taken from the model's own forcing/analysis field rather than a dedicated ocean reanalysis.
Depth profile
×
Min
Average
Max
Markers
Format
Profile
Route
Calculate
Sea surface temperature
Min
—
Average
—
Max
—
Copernicus Marine SST (C3S/ESA CCI reanalysis)
© AlluZeff
Location
Source
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Value
Statistics
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Season
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Location
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Statistics
Period
Season
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Statistics
Period
Season
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Location
Latitude
Longitude
Value
Parameter
Source
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