Is there a way to determine OG after topping with H20?

[Griffin495]

I brewed a Stout on Sunday and forgot to recalculate my boil off as I was using a propane burner rather than my stove (1 gallon an hour vs. 0.5 G). As a result I ended up with 2.25 gallons rather than the 2.75 gallons I was shooting for. My OG was 1.045. In a moment of stupidity I guess, I ended up topping off the fermenter with .5 gallon of water rather than just going with what I had, then didn't stir it up or take another reading. Is there any way to calculate how water will dilute wort in order to figure out about what the OG will be now? It doesn't have to be accurate, just in the ballpark. I know it will be fine, it will make beer and it might even be great if not as high an ABV as I was planning for. Just out of curiosity.

 

[Griffin495]

Never mind. I found it. For some reason I couldn't find it last night

https://www.brewersfriend.com/dilution-and-boiloff-gravity-calculator

looks like it will be 1.037 if its correct.

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