So I got a new cycle computer that tracks current altitude as well as cumulative gain or loss. In the instructions it says to set the unit to whatever your current altitude is and reset as needed for weather changes. The only way I can be sure as to what my altitude is would be to drive to the beach and set it for 10 feet.
Is there a web site where it will tell the altitude of a particular address? Or will I have to drive to the beach before every ride? 
Where do you live?
If you’re in the US, it looks like TopoZone has topographic maps for the entire country. You could try searching for your home there and finding a spot height or contour line nearby.
…or if you’re passing Heathrow Airport it’s 28 ft above sea level
Why would you have to drive to the beach before every ride? Wouldn’t knowing the altitude once be enough? Otherwise, how is a website going to help? Some GPS would help. But be aware, unless your computer has a GPS unit (in which case you wouldn’t need to drive to the beach), you’re going to get approximate info anyway.
Be sure to recalibrate often. Most altimeters are really just barometers, so the reading will change with the weather.
John yes they are and yes they will.
I am on the road this week in Northern California. Yesterday on my ride it told me I was 10 feet below sea level, somehow I don’t think so.
I want to be able to recalibrate before each ride, but I need a clue as to what my correct altitude is.
RM Mentock Yeah, so how do I find out the correct altitude for my office in Northern California (or my home in So Cal) so I can set it correctly to start with? Obviously if I can figure out what the correct altitude is for a particular location one time I can write that info down, and use it to recalibrate my computer each time to accommodate any weather changes. The problem is finding out what is my correct altitude is the first time for each new location.
Crimmsy That Topo site might have possibilities, I have to spend some more time there. Thanks.
When I first bought my altimeter for my Mtn Bike (before the internet was popular) I went out and bought some topo maps. They’re pretty cool to have in any case.
Where in NorCal are you riding? Most towns have an “altitude” listed on the town/city limit signs, and that usually refers to the town hall or city center.
I ride mostly around Los Gatos/Saratoga area, and I know the town center for LG is 400 ft.
Right now I am in Pleasanton, I live in San Fernando Valley, I am up here on business.
Topo maps are the way to go, yes. It can occasionally be tricky reading the values of the contours, but it is the best way.
For any UK folks reading this thread, if you want to know your altitude, go to http://www.get-a-map.co.uk/getamap/ , click on the Get A Map button, then enter your postcode. You should then be able to read the contours or find a spot height (it is sometimes easier if you zoom in to the largest scale).
Colophon (73m asl )
The USGS has a map viewer thingie here.
http://nationalmap.gov/index.html
You can find a spot and there’s an elevation tool which tells you the elevation of the spot you click on.
You could also take this as an excuse to go buy a GPS receiver.
Perfect! Just what I was looking for! My office is 343 feet ASL, and my house is 1080 feet.
Zippyh You rock! Thanks.
You can double check this by setting it (at home) to 1080 feet and then ride down to the beach that you said was at 10 ft. See if it shows 10 when you get there.
I just looked at my computer and it appears that it only keeps track of altitude if it is recording heart rate, or the bike is moving. I am on the 6th floor of a hotel, and it shows the altitude I set for my office.
So I will need to look up my starting altitude for each location I ride, and go from there.