Hello,
I am coding for Pressure units convertor in Excel2007, I have written the nested IF function about 11 nested IF function's levels, I have made a drop down list for different pressure units. I want to change the pressure conversion in all five cells(from cell O14 to O18) at the same time ,as I changes unit from drop down list, but I am not able to implement the changes on all five cells, this code only changes cell O14 values, but rest of four cells(O15-O18) values does not changes appropriately. Tell me the solution, How i implement the code and reduce this code to achieve the same functionality or alternate of Nested If function that can achieve the same task.
Thanks
Code is given below

Drop Down List cell O13 for Pressure Convertor

in.H2o
in.Hg
mmH2o
mmHg/Torr
Kg/Cm2
bar
mbar
Pa
Kpa
Mpa
PSI
atm

Code at Cell O14 (0% Pressure Value)

=IF((O13="in.H2O"),ROUNDUP((C12*27.71),2),IF((O13="in.Hg"),ROUNDUP((C12*2.036),2),IF((O13="mmH2O"),ROUNDUP((C12*703.1),2),IF((O13="mm/Hg"),ROUNDUP((C12*51.75),2),IF((O13="Kg/Cm2"),ROUNDUP((C12*0.703),2),IF((O13="bar"),ROUNDUP((C12*0.689),2),IF((O13="mbar"),ROUNDUP((C13*68.95),2),IF((O13="Pa"),ROUNDUP((C12*6895),2),IF((O13="Kpa"),ROUNDUP((C12*6.895),2),IF((O13="MPa"),ROUNDUP((C12*0.0068947),2),IF((O13="PSI"),ROUNDUP((C12*1),3),("Select Regtrd Unit"))))))))))))

Code at Cell O15 (25% Pressure Value)

=IF((O13="in.H2O"),ROUNDUP(((C14/4)-C12),3),IF((O13="in.Hg"),ROUNDUP(((C14/4)-C12),3),IF((O13="mmH2O"),ROUNDUP(((C14/4)-C12),3),IF((O13="mm/Hg"),ROUNDUP(((C14/4)-C12),3),IF((O13="Kg/Cm2"),ROUNDUP(((C14/4)-C12),3),IF((O13="bar"),ROUNDUP(((C14/4)-C12),3),IF((O13="mbar"),ROUNDUP(((C14/4)-C12),3),IF((O13="Pa"),ROUNDUP(((C14/4)-C12),3),IF((O13="Kpa"),ROUNDUP(((C14/4)-C12),3),IF((O13="MPa"),ROUNDUP(((C14/4)-C12),3),IF((O13="PSI"),ROUNDUP(((C14/4)-C12),3),("Select Regtrd Unit"))))))))))))


Code at Cell O16 (50% Pressure Value)

=IF((O13="in.H2O"),ROUNDUP(((C14/2)-C12),3),IF((O13="in.Hg"),ROUNDUP(((C14/2)-C12),3),IF((O13="mmH2O"),ROUNDUP(((C14/2)-C12),3),IF((O13="mm/Hg"),ROUNDUP(((C14/2)-C12),3),IF((O13="Kg/Cm2"),ROUNDUP(((C14/2)-C12),3),IF((O13="bar"),ROUNDUP(((C14/2)-C12),3),IF((O13="mbar"),ROUNDUP(((C14/2)-C12),3),IF((O13="Pa"),ROUNDUP(((C14/2)-C12),3),IF((O13="Kpa"),ROUNDUP(((C14/2)-C12),3),IF((O13="MPa"),ROUNDUP(((C14/2)-C12),3),IF((O13="PSI"),ROUNDUP(((C14/2)-C12),3),("Select Regtrd Unit"))))))))))))

Code at Cell O17 (75% Pressure Value)

=IF((O13="in.H2O"),ROUNDUP((((C14/4)*3)-C12),3),IF((O13="in.Hg"),ROUNDUP((((C14/4)*3)-C12),3),IF((O13="mmH2O"),ROUNDUP((((C14/4)*3)-C12),3),IF((O13="mm/Hg"),ROUNDUP((((C14/4)*3)-C12),3),IF((O13="Kg/Cm2"),ROUNDUP((((C14/4)*3)-C12),3),IF((O13="bar"),ROUNDUP((((C14/4)*3)-C12),3),IF((O13="mbar"),ROUNDUP((((C14/4)*3)-C12),3),IF((O13="Pa"),ROUNDUP((((C14/4)*3)-C12),3),IF((O13="Kpa"),ROUNDUP((((C14/4)*3)-C12),3),IF((O13="MPa"),ROUNDUP((((C14/4)*3)-C12),3),IF((O13="PSI"),ROUNDUP((((C14/4)*3)-C12),3),("Select Regtrd Unit"))))))))))))

Code at Cell O18 (100% Pressure Value)

=IF((O13="in.H2O"),ROUNDUP((((C14/4)*4)-C12),3),IF((O13="in.Hg"),ROUNDUP((((C14/4)*4)-C12),3),IF((O13="mmH2O"),ROUNDUP((((C14/4)*4)-C12),3),IF((O13="mm/Hg"),ROUNDUP((((C14/4)*4)-C12),3),IF((O13="Kg/Cm2"),ROUNDUP((((C14/4)*4)-C12),3),IF((O13="bar"),ROUNDUP((((C14/4)*4)-C12),3),IF((O13="mbar"),ROUNDUP((((C14/4)*4)-C12),3),IF((O13="Pa"),ROUNDUP((((C14/4)*4)-C12),3),IF((O13="Kpa"),ROUNDUP((((C14/4)*4)-C12),3),IF((O13="MPa"),ROUNDUP((((C14/4)*4)-C12),3),IF((O13="PSI"),ROUNDUP((((C14/4)*4)-C12),3),("Select Regtrd Unit"))))))))))))