Good afternoon

Im Lee, and im fairly new to vba so im hoping for some help to the below that i just cannot seem to solve

so i have a userform project that captures tenant data. everything is working very well so far except for the below issue i have now encountered:

i have two textboxes (textbox18 ""current water reading"") and (textbox11 ""previous water reading"").

i have textbox64 that automatically updates when input numbers in textbox18 and textbox11

textbox64=(textbox18-textbox11)

the difference in textbox64 must then multiplied by one of 5 different textboxes that hold specific data

so if textbox64=5 then it is multiplied by the data in textbox70 and so on

the criteria i have been given is as follows:
if textbox64 is between 0-6 then multiply by textbox70 (6.82)
if textbox64 is between 6.1-25 then multiply by textbox71 (45.43)
if textbox64 is between 25.1-30 then multiply by textbox72 (60.34)
if textbox64 is between 30.1-45 then multiply by textbox73 (82.82)
if textbox64 is greater than 45 then multiply by textbox74 (123.02)

***the figures in textboxes70-74 will be updated yearly by a different userform***

my problem is that i cannot seem to find a way to multiply by the correct textbox only when textbox64 is calculated.

and on top of that, the correct calculation from one of those (textbox64*textbox70 to 74) must then update in real time to textbox21

***textbox64, textbox70-74 will all be invisible on the userform***

am i reaching for something impossible?

i have spent many hours reading through these posts and im hoping a genius would be able to offer a solution for me.

please help!

ps: i hope i have followed the forum rules with this post and if not, i do sincerely apologise.