How much Sparge water?

I've got two all grain brews under my belt and I still don't know the proper amount of sparge water to use I just sparge with the amount of wort I need in my pot after I let the wort run out. Is this the correct way to do things?

In a word...yes. you want to calculate what you'll need taking everything into consideration. Just use a calculator like this one. http://www.brew365.com/mash_sparge_water_calculator.php

Typical batch - 12 to 14lbs grain, after mashing I sparge till I get about 7 gallons. After the boil I end up with a little less than 6 gallons and after a primary, and secondary with dry hopping I end up with 5 gallons in the keg. With this approach I get about 1.060 post boil OG with 12 lbs of grain and around 1.070 with 14 lbs.

Do you batch or fly sparge?

I batch sparge so after first runnings are collected i check the volume gathered and then sparge with the difference between pre boil volume and collected 1st runnings.

I use the Brew365 calculator and I have all my variables dialed in on my system. Take very careful and detailed notes on exactly how much water you use and have at each step of the process. Then, after a couple brews you will know what your variables are. For example, the default "Equipment Loss" variable of 1 gallon is way too high for my system. If I use that value, I'll end up having a huge sparge amount and not being able to take it all and then having a big loss in efficiency. Instead, I use 0.25 gallons. Also, my percent boil-off is always 13%, not 10%. So the first time you use this calculator try to estimate what each value should be (except for the relatively constant ones like wort shrinkage), take very careful notes, then adjust them accordingly the second and third time you brew. After using this calculator about 30 times, I always have the amounts I need. (Also, this is a side note, but another thing that can significantly affect your yield post-fermentation is whether you use hop bags or not. Definitely use hop bags, if you don't, the sediment can congeal with the trub and end up stealing a lot of beer away from your final yield.)

There is another batch sparge calculator at http://www.hopandgrain.com/batchspargecalc.aspx which I always use.

I guess I'm batch sparging I don't know the difference between the two

Batch sparging is where you collect all of the water you add at initial striking, then close your valve and add some amount of water at a higher temperature to hopefully bring the bed up to around 168 deg F, let it sit and drain it off. Some people two two rounds of this and maybe even more, but you're limited by temperature and volume.

Fly sparging is where you begin draining and after vorlaufing you begin to add fresh water at a higher temp to bring the bed up and wash the bed of sugar "on the fly."

Batch sparging is easier to calculate how much to add for the sparge, since your grain has already soaked up all the water it will. GillSwill mentions this.

Either way, though, it's better to know how much you need going in and the calculators provided above will do that for you or a program like BeerSmith. If you know prior to mashing, then you can treat your water all at once if you have a big enough HLT, or you can prep your sparge water while mashing and save time. Saving time and water is good.

https://www.homebrewtalk.com/f36/attention-new-all-grain-brewers-30466/
this helped me out greatly, I am getting good numbers now that I use the info off this thread...

Batch sparging is where the water is added all at once, fly sparging is where it filters through at a more or less constant rate. Batch sparging MAY include two batches of water around 170 degrees, but most of the time it is just one. Based on anecdotal evidence, vast majority of homebrewers use the batch sparging method.

Wow thank you all for this helpful info. I am looking forward to my next brew

There is a great sticky here about maximizing efficiency while batch sparging. Denny Conn also has this wonderful batch sparging article http://hbd.org/cascade/dennybrew/
Happy brewing.