did I figure these right?

I'm trying to figure my brewing efficiency...

I did two 2 1/2 gallon batches.
One was a dry Irish stout and the other a chocolate stout.
the Irish stout was a BIAB
90 min mash
mash out temp to 170.
Here is the grain bill
3 lbs maris otter
1/2 lb flaked barley
1/2 lb chocolate malt (simpsons)
.10 lb acidulated malt
.10 lb roasted barley
3.5 gallons preboil, hyrdometer reading of 1.038
post boil hydrometer reading of 1.044

second beer was the chocolate stout
BIAB with 60 minute mash, using ice cream motor for stirring
no mash out of higher temps ...because, quite frankly, I forgot..
here is the grain bill
4 lbs maris otter
7.2 oz flaked barley
6 oz carafa III
6 oz chocolate malt (simpsons)
2 oz extra dark crystal
4 gallons preboil, hydrometer reading of 1.044
post boil hydrometer reading of 1.050

from what I've come up with using brewers friend brewhouse efficiency calculator, my efficiency with the Irish stout was 87.21% and the chocolate stout was 90.36% ...could that be correct?????

I know from testing the BIAB from prior brewing sessions, I was running around 65%...WTH?

anybody?

Your math looks very off.

Take [Total gravity points]/[# of gallons]; then divide your recorded gravity by the answer to that first equation and you'll get your efficiency. Or you can order a brewing software and save you some math.

I checked the math with ProMash database gravity points, his recipe & preboil volumes and got the same efficiencies he has.

Ok, nevermind. I was calculating based on the final gravities (duh).

Good job. Both of you.

thats just super then!!
I guess the constant stirring of the mash really did wonders!
Thanks for the input guys...
oh and I'm a gal brewing! LOL
but it's all good.