Hello, I’m trying to figure out what I thought was a simple formula but it’s not working no matter what I do. I’m trying to get airtable multiple a $ amount by % field to come up with the after tax price. I currently have a Table called Member Fee which is a Dollar amount price before tax. that table has 2 fields the main one being Member Fee, the second is simple the name of the program that has that price. I have another able for GST/HST (which is what the taxes are called). In that table I Also have 2 field the Tax percentage which is in a value of 1.000 because we have the province of QC who’s tax in %14.975. In my main table the 3 fields I’m trying to calculate are called Member fee which is linked to the member fee table, GST/HST which is linked to the GST/HST table and Total Fee. The total fee field format is set to Currency with a precision of $1.00 and the formula I’m using is VALUE({Member Fee})*{GST/HST} however this does not seem to be working. Can someone please help me?

# Formula not working

What error are you getting? Both Fields contains numbers? The only thing you must have in mind is that a Percentage field is set relating to 1, not to 100, so you have to multiply the result by 100.

Formula: `A/B*100`

**W_Vann_Hall**#5

You’re halfway there — but your problem also reveals an odd ‘gotcha’ in the way Airtable works.

First, the solution. This formula should work:

```
VALUE({Member Fee})*VALUE({GST/HST})
```

The oddity is that `VALUE({GST/HST})`

equals `0.13`

. *What’s so strange about that?* you ask. Well, if you go to the `[GST/HST]`

table, you’ll find the value of the primary field for the record named `13%`

is `13`

. That is to say, a percent field with the value of `13%`

, used in a formula, has a numeric value of `13`

. This is an Airtable bug of long standing that essentially has been grandfathered into the product because of the number of formulas it would break if corrected. However, something I hadn’t previously realized is that calculating the value of the *string* `'13%'`

returns the correct numeric value of `0.13`

. In your case, when you refer to a linked-record whose primary field is a percent field, the reference is automatically converted to a string — which is why you were receiving `#ERROR!`

responses. Since it’s a string, though, the `VALUE()`

function behaves as it should, returning the correct value.

The reason I’m going through all this is that if you perform calculations in the `[GST/HST]`

table, you’ll need to treat that `13%`

value differently than you do here. One possible method would be to wrap it as follows:

```
VALUE({GST/HST}&'%')
```

(Actually, that seems to be a safe wrapper for any percentage; that is, if I append `'%'`

to the string `'13%'`

I get `'13%%'`

, and `VALUE('13%%')`

returns `0.13`

.)