Calculating Leftover Percentages

Have you all come across a solution to calculate leftover percentages within certain inputs? Here’s what I’m trying to achieve…

Step #1: User puts in their budget amount
Step #2: User puts in their first invoice percentage amount
Step #3: I want the app to auto-populate the remaining percentage for the second invoice. I know how to get it to populate for the dollar amount… just not the percentages.


The mathematical equation in the “Initial Content” SHOULD be “100%-Input 75%'s value”… but that isn’t working. Thoughts? Workarounds? Or maybe a solution to use something else?


My guess is that it doesn’t understand the percent symbol in 100%, so perhaps try 100-input_value or 1-input_value.

Already tried that. The issue is that when you do…

  • 1-Input 75%'s value, you get 100
  • 100-Input 75%'s value, you get 10000

And when either one is used, it instantly shows 100% or 10000% respectively and not the placeholder text of “25%”.

This has to be a basic math equation… but something’s not clicking.

Maybe you want this as a condition, and to only have it applied when other conditions are true?

Also, perhaps instead of using 25% as a placeholder, you actually want that to be the default value. Same goes for the 75%.

Usually, placeholders are used to describe the input (e.g., first name) and then the default value might be the person’s actual name (e.g., John).

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Hmmm… ok, I’ll have to read up on “conditions.”

I don’t want the placeholder percentages to be used as the actually inputs because the user may want to split their invoice payments up differently (ie. 50/50, 25/75, 80/20, etc). The placeholder is just for a visual reference.

Appreciate the comments.

Got it.

So, you can use 25% as the placeholder. Then, set a condition: when “input_75’s value is not empty and input_75 is valid” then initial content equal to 1-input_75’s value.

This will show 25% as a placeholder until the user enters a value in the input_75 field.

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I’m stepping out for a bit but will get back with this tonight. “…is not empty” is not an option. I’m trying to set this “condition” to the 25% input. If that’s wrong, let me know.

in place of “is not” you’ll also find an option for “is not empty”

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Yes, percentages go from 0 to 1. A number formatted as 25.2% is the decimal 0.252.

(It’s the number you’d multiply by to extract that percentage, see?)

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(Subtle correction, of course percentages can be greater or less than that, but 0 is 0% and 1 is 100% is my point…)

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Thanks for the reply but for whatever reason the “initial content” doesn’t like having “1-” in front of “Input 75%'s value”. Look at images attached… the last image shows what it looks like in the end. The fourth image shows what it looks like live.


Try this …

first input’s value * -1 + 1

Which is equivalent to

1 - first input’s value

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What the OP is trying to do is so hinky. OP, rethink your approach. And read my post. Thanks and you’re welcome.