I finally got tired of googling my own forum posts to find my formulas, so I put together a pretty basic calculator for estimating batch-sparging efficiency. It really only does one thing, but it should do it pretty well. Reality checks are always appreciated. Any feedback or requests, let me know.
http://seanterrill.com/2013/10/05/batch-sparging-calculator/
Cool! Thanks Sean! I’ll give it a shot this weekend.
Any way to take mash efficiency into account? You assume 100%, I’m usually around 96-98%.
Very nice Sean!
Thanks!
You could just knock a bit off the potential extract field, to 74% or so. I typically plug in 73% (~94% conversion efficiency) to give myself some wiggle room, then dilute in the kettle if I’m more than a few points off.
Cool. I’ll try that.
Putting in my numbers from yesterday’s brew, I can’t get the post boil gravity from your calculator to match what mine really was.
Nice. I am going to have to actually measure the fluid left in the grist (not absorbed) after run off to get a reliable figure for the lauter dead space, otherwise it looks like a ready addition to the brewing arsenal. Can’t wait to give it a try! Thanks, Sean.
That’s really weird, assuming the pre-boil gravity was right. Those two numbers are just the same amount of extract divided by the two different volumes.
Do your pre- and post-boil gravity/volumes work out? SG1V1 = SG2V2?
I’ll check and let ya know.
That’s because you don’t really need a batch sparging calculator. ;D 
Don’t you have something you should be doing in the brewery?
I brewed a low-gravity Belgian Blonde against the calculator today. All volumes were spot-on and gravities within 0.4°P. I guess I knew that it would work for my numbers, though…
I’ll double check my numbers. I also plan to brew within the next few days (hey, I’m not working for a few months, why not?) and try it again.
I’ll give it a whirl on Sunday during my brew session. 
Just tried it out yesterday and it worked great!
looks good. I’ll give it a try this weekend. I did notice one thing which is it appears in the calculated area the Liter/Gallon choice isn’t totally working on the First and Second runnings fields. The tag changes to L when I set it to liters but the actual volumes remain in Gallons.
Results
Pre-Boil: 48.99 L at 10.1°P (1.04) First Runnings: 6.34 L at 17.2°P (1.07)
Post-Boil: 40 L at 12.3°P (1.05) Second Runnings: 6.6 L at 4.4°P (1.017)
Boiloff: 8.99 L (18.3%)
Lauter Efficiency: 83.4%
What’s up Denny…did you get a work furlough?
I completely forgot to try this calculator during my brewday Sunday…Sorry Sean.
I’ll give it a try sooner than later.
Long story, Ron, but I’m on “paid administrative leave”. I may just retire rather than go back.
I forgot to enter my numbers, too, but I’ve got the info so I’ll try it later.
Thanks for catching that. It should be fixed now.
I dunno, Denny… paid leave sounds like just about the ideal situation to me…
Hope everything works out for you.