help determining ABV

I goofed when brewing my IIPA yesterday, took my gravity reading prior to adding 102oz of water to my wort (came in at 1.100!). After transferring to my 6gal carboy I added the 102oz (apprx 3/4 gal) of water and my turkey baster wouldn't reach to wort to pull the more accurate OG. Any way I can estimate my OG knowing that it was 1.100 prior to adding 102oz of spring water? Any help/insight would be appreciated..

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Dave's Dreaded Actual Specific Gravity Calculator

It's a fun tool to calculate ABV

According to Beer Smith II

Assuming you started with 4.25 gallons of 1.100 wort then added 102 oz of water, the gravity will be 1.084

Dan said:

According to Beer Smith II

Assuming you started with 4.25 gallons of 1.100 wort then added 102 oz of water, the gravity will be 1.084

Click to expand...

Much appreciated Dan!

Brew software takes a lot of guess work out of brewing!

Abv=og-fg*131.25

adjusted OG = starting OG * starting volume / adjusted volume
100 * 4.25 / 5 = 1.085