Problem with calculation

Hello!

I am trying to build a calorie-calculator (Harris & Benedict formula) for my website using Ninja Forms. For this formula I use the ‘complex’ equation and everything seems to work. When I fill in the values (weight, height, age + activity) the form gives the correct outcome based on the formula below:

(88.362 * 1) + (13.397 * field_53) + (4.799 * field_54) – (5.677 * field_55)

= this is how the exact equation looks in my ninja form settings.

However, when I open the complete form on my website it already shows 88 in the area in which the outcome is shown. When I use the calculator the correct answer is shown, but when nothing is filled in, it shows 88 as ‘starting value’. I know why it shows 88, this is de first given value in the equation (this factor does not depend on any variable input). How can I make sure the 88 is NOT shown as a standard outcome value. I want this to be empty and only show a number / value when someone fills in the form.

I hope someone can help me ??

Thanks in advance!

Best regards,

Marvin Grouw