This page will calculate the density of a balsa sheet. 
All units are in decimal inches EXCEPT for weight which is in grams 

To select the sheet thickness from a list instead of manually entering click here
Sheet Width (Decimal inches ie.: 1.5) 

Sheet Length (Decimal inches ie.: 35.5) 

Sheet Thickness (Decimal inches ie.: .053) 

Sheet Weight (Decimal grams ie.: 11.2)