question about Maltose Falcons / Drew Beechum's Excel IBU calculator

I’ve been using this IBU balancing spreadsheet http://www.maltosefalcons.com/tech/ibu-calculator-hop-scheduler-analysis for my last few beers as I find it better than a lot of website calculators and it has FWH which a lot of other calcs don’t… I am often scaling 5 gal recipes to 10 or 15 gals…

Does anyone know what IBU formula is being used in there? It seems to give me higher numbers than both Rager and Tinseth, at least as shown on these two sites… http://www.brew365.com/ibu_calculator.php and http://www.rooftopbrew.net/ibu.php.  In the end, I guess it doesn’t matter as long as I consistently use one calculator, but I’m just interested.

-red

hey, it took me a while to find it, because, wow, i’d forgotten…

it’s Ray Daniel’s formula from DGB.

and yeha, it’s good for ball parking, but if i were doing it again, i’d implement rager or tinseth.

Hey thanks Drew. I’ll keep using it, and know that it is at least consistent…

-red