Computed multiplication

I have a webform where I am using the Twig Computed module to calculate an amount. It is simple and straight forward: I have a field that captures the amount and I'm using Twig to multiply it to find the fee; the fee amount is a fixed rate

The Computed Value/Markup is {{ data['license_amount']|number_format(2) * 0.019 }}. It works when data['license_amount'] is lower than 999; it shows a wrong total when data['license_amount'] is higher than 999.

If the amount is 500 the value is 9.5 as it should.

If the amount is 5000 the value is returned as 0.095

You should drop the number_format altogether (not sure what the requirement is), or place it at the end of the calculation, i.e.

{{ (data['license_amount'] * 0.019)|number_format(2) }}

number_format is a wrapper around PHP's number_format function

From PHP's documentation page:

// english notation (default)
$english_format_number = number_format($number);
// 1,235

// French notation
$nombre_format_francais = number_format($number, 2, ',', ' ');
// 1 234,56

It seems like you are running the calculation on something like 5'000 or 5,000 (depending on your locale), which would explain the results you are getting.

Good luck!