**RogerYelvington01**Hey guys!

Currently I have this formula in the "remaining balance" field:

[({remainingPayments}*{memberDues})+{remainingPayments}*{tanningDues104}]

There are currently two problems:

1. If nothing is entered into the "tanning dues rate" field, then it shows an inaccurately high balance

2. If 0 or 0.00 is entered into the "tanning dues rate" field, no calculation will result or show in the remaining balance field

If a client does select to add tanning, and you type in the amount, 15.00 - then the calculation is accurate.

Please advise, thank you!

**Cesar**It appears this is due to the fact you are multiplying a zero thus making the total a zero. If in case you would need to calculate {remainingPayments}*{tanningDues104} with no {tanningDues104} payment, then adding a 1 to the {tanningDues104} field should not modify the price.

I would suggest to leave that fields minimum/default amount value to 1 instead of zero.

http://form.jotformpro.com/form/40076137364957

Example Form:Do let us know if you need further assistance, thank you.

**RogerYelvington01**Thank you for the suggestion! That helps a little - however with the following current formula, the Remaining Balance amount will still be inaccurate for clients that opt out, and do not want to pay for tanning:

[({Remaining}*{memberDues})+{Remaining}*{tanningDues104}]

Example:

Remaining Payments: 23

Member Dues: $39.99

Tanning Dues: $1 (Default Value, even when does not want tanning)

Remaining Balance: $919.77However our calculation currently results as $942.77, which is adding the tanning amount 1x23, making the balance $23 too high (and the client unhappy, as they do not want any charge for the service unless the opt-in). The calculation works when the client opts in for tanning, but increases the balance by the number of payments even when they opt out of tanning.

Please advise, thank you!

Roger

- JotForm Support
**jonathan**Hi Roger,

Unfortuantely, you cannot use

**condition logic**within the calculation fields.Like in your case, the condition

IF {tanningDues104} = 0

THEN [({Remaining}*{memberDues})+{Remaining}]

IF {tanningDues104} > 0

THEN [({Remaining}*{memberDues})+{Remaining}+{tanningDues104}]

Can you please tell us if my sample condition above is applicable to your desired computation?

I think we can do this on the form by using 2 tanningDues field.. and use it in computation.

It can be a lot of work if we can only use the

**form builder**for all the custom computation.BUT it can be a lot easeir if you can use the

**form's source code embed**because you can easily create a custom javascript computation code to work in your form. This will require embedding of the form's source code into a website.Inform us of your feedback on this.

Thank.s