Excel VBA using a few Named Ranges in a formula

Question

I am trying to use a few Named Ranges together in a formula in VBA, however it seems to take very long for excel to calculate. The Named Ranges have almost 70k of data each (All have the same number of rows). Below is an example of the code:

Dim i, erow, ecol As Long

erow = Sheets("Sheet1").Range("A11").End(xlDown).Row
ecol = Sheets("Sheet1").Range("A11").End(xlToRight).Column

Sheets("Sheet1").Range(Cells(12, ecol + 2), Cells(erow, ecol + 2)).Formula = "=(0.03 - Ith_LT) * (a_LI_LT * 0.03 ^ 2 + b_LI_LT * 0.03 + c_LI_LT)

Ith_LT, a_LI_LT, b_LI_LT, c_LI_LT are the named ranges.

I am trying to speed this up by first storing the named ranges in memory then calling it but to no avail. Below is my code.

Dim i, erow, ecol As Long
Dim Ith, a, b, c As Variant

erow = Sheets("Sheet1").Range("A11").End(xlDown).Row
ecol = Sheets("Sheet1").Range("A11").End(xlToRight).Column
Ith = Range("Ith_LT")
a = Range("a_LI_LT")
b = Range("b_LI_LT")
c = Range("c_LI_LT")
Sheets("Sheet1").Range(Cells(12, ecol + 2), Cells(erow, ecol + 2)).Value = (0.03 - Ith) * (a * 0.03 ^ 2 + b * 0.03 + c)

When i run this, a type mismatch error pops up. Is there any way to make this work? or are there anyway to make this code run faster? Thank you.

Answer 1

In your variable declaration you only define the last varibale with the given type:

Dim i, erow, ecol As Long
Dim Ith, a, b, c As Variant

Instead of variant you should use the type range instead of variant for the second line

Dim Ith as range, a as range, b as range, c  as range

Afterwards you use this line to use the named ranges

Set Ith = Range("Ith_LT")

Answer 2

@Zabjaku Based on your comment I'm assuming all ranges are single column and the final output is to be populated as a result of formula then you can use this.

This will fill your output column and if the named range changes you don't have to change your formula.

Sheets("Sheet1").Range(Cells(12, ecol + 2), Cells(erow, ecol + 2)).Value = "=(0.03-" & Replace(Range("Ith_LT").Cells(1, 1).Address, "$", "") & ")*(" & Replace(Range("a_LI_LT").Cells(1, 1).Address, "$", "") & "*0.03^2+" & Replace(Range("b_LI_LT").Cells(1, 1).Address, "$", "") & "*0.03+" & Replace(Range("c_LI_LT").Cells(1, 1).Address, "$", "") & ")"