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(12C) Calculate the Amount of Sales Tax
08-08-2022, 06:40 AM (This post was last modified: 08-08-2022 06:42 AM by Gamo.)
Post: #1
(12C) Calculate the Amount of Sales Tax
Find this article interesting about

"How do I calculate the amount of sales tax that is included in total receipts?"

Here is the link:

Some calculator do have the specific TAX function to calculate TAX+ and TAX-

This article ask on how to calculate the TAX- to find the amount not include tax

with tax amount.

On HP-12C Financial Calculator doesn't have the TAX- function but

the TVM function will do this problem just fine.

I'll use the example problem from this article to shown on how to set up.

Total included Tax is $481.50
Tax Rate is 7%
Find Total not include Tax and Tax amount.

Set Up Data:
Input 1 to [ n ] // this part just to always input 1
Input 7 to [ i ] // this is for your Tax Rate in this case is 7

Input 481.50 to [FV]

To Run Press [PV] and the answer is -450 just ignore the negative sign
Press [RCL] [FV] [+] and the answer is 31.50

So Amount not include Tax is $450 and Tax amount is $31.50

To check for correction add both up 450 + 31.50 = 481.50

The [PV] is for Amount not include tax (Exclusive Tax)
The [FV] is for Amount include tax (Inclusive Tax)

So user can either look for Exclusive or Inclusive Tax with this TVM function.

I think someone might just think oh this is just a simple tax calculations.
I know in this case one can just divide the Amount include tax with 1.07 and
will get quicker answer right? ( 481.50 ÷ 1.07 = 450 )
That right but with this handy TVM function it is much quicker once the data
is already input on [n] and [i] user just input amount either at [PV] or [FV] in
either case will help user do it much faster when doing lot of tax related calculations.
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08-09-2022, 09:10 AM
Post: #2
RE: (12C) Calculate the Amount of Sales Tax
Thank you Gama for the thread.

I use HP-17bII and HP 19bII among others in the office.
PV and FV works here too.

Input [PV[ (= net)
Press [FV] (= gross)
Press [+] (= tax)
saves even 2 keystrokes compared to HP-12c


8years elementary school, 2y business school; no bachelor/master, etc.;
but always interested in simple mathematics & calculators
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