I lost my Minecraft house. How can I find it? [duplicate]

If you have the correct supplies you could craft a compass. A compass will always point to your original spawn. To craft a compass you will need to arrange 4 iron ingots and 1 redstone, like so:

If you lack these supplies and want an alternative to using mod's you could press F3 and this will display the debug screen. On this screen should be 3 coordinates (X, Y, Z). If your house is near your spawn (the place where you first appeared within that level), then you could just walk back to (X:0, Z:0). Generally you'll spawn within about a 100 blocks of (X:0, Z:0).

If you're fine with doing so, you could open up your world in one of the programs listed in the Programs and Editors page of the Minecraft Wiki, to view your map and attempt to figure out where your home is in relation to where you currently are. Eihort looks like a great tool (and is compatible with Windows, Mac OS X, and Linux), because it shows the coordinates of where you are currently hovering (so when you find your house, you can easily locate it in-game via F3). If you don't need something quite that powerful, mcmap and Tectonicus are also good.

In the place that you are lost, copy the coordinates down on paper. Then make a chest and put all the good things that you have in that chest, and after that kill yourself/ allow yourself to be killed. Then you should spawn at home. At your house copy down those coordinates, then go to the first set of coordinates you copied and all your stuff will be in the chest, then you can use your home coordinates to get home again.

If you don't want to use any external tools then you could build a tower where you are and climb to the top. Then turn the render distance to maximum so you can see as far as possible.

This may enable you to spot some features you recognise and will also give you a reference point in case you get lost in the future.

I'd recommend Zan's Minimap, which is a clientside mod that gives you a great, customizable map. Of particular use to you is the feature that allows you to set waypoints on your map, so you will never lose a certain place again.

Just be aware that the 'Threading' option will corrupt your world in a solo game if turned on (so leave it off).