Instant Option Price Calculator

This OpenCart extension provides an alternative product option price calculation. The standard OpenCart price calculation only adds or subtracts the prices of the chosen product options to the total product price, whereas this extension offers more complex option price calculations using a pre-defined option price formula.

Also, on the frontend product page, whenever the user selects an option the total product price is instantly re-calculated and displayed. This is different from a standard OpenCart where the total product price won't be seen until the user goes to the cart checkout.


For OpenCart 2.x releases:

A pre-installed VQmod software (a dynamic OpenCart modification system based on XML specifications) is needed.

You can get a free Integrated VQmod either from:

Or from:

For OpenCart 3.x releases:

No extra modification system is required, it uses the built-in OpenCart event handlers and OCmod.


For OpenCart 2.x releases:

Simply upload the folders and files from the 'upload' directory to your OpenCart server's main directory.

For OpenCart 3.x releases:

  1. Log into the OpenCart admin backend with your administrator account
  2. Install the extension via the Extensions > Installer
  3. Go to System > Users > User Groups > Administrator and make sure the access and modify permissions are set for 'extension/module/option_price_calculator'
  4. Go to Extensions > Extensions > Modules > Option Price Calculator > edit to enable this module

Then, in the Opencart admin backend, go to Extensions > Modifications and click on the Refresh button.


To overwrite the standard OpenCart option price calculation, go to a product page in the admin backend and click on the  'Option' tab. You will see 2 additional optional fields:

Option Price Formula
Option Price Comment

Option Price Formula Example:

Assuming the product options 'width' and 'height' are defined, and you want to multiply the width by height and then by 15% of the product price and finally add 1.55 to it, then use this formula:

option_value('width') * option_value('height') * 
(product_price()*15/100) + 1.55

Notice that an option price calculation based on a formula is always done before taxes (e.g. VAT) are applied!

Possible operators:

? :                   (conditional ternary operator) 
|| &&                (boolean operators
+ - * / (arithmetic operators)
< <= == != > >= (relational operators)
Use brackets to overwrite operator precedence:
(  )

Built-in functions:

option_value( <option> )
option_price( <option> )
option_weight( <option> )
option_points( <option>
strlen( <expr> )
mb_strlen( <expr> )
exist_option( <string> )
extract_integer( <expr> )

Note: <option> is usually an option name, <expr> is an expression

Further help and customized versions

This extension has been successfully tested for a standard  OpenCart,, and It should also work with other OpenCart 2.x or 3.0.x versions.

If you need a customized version of this extension, let us know and we can create one for a charge.

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  • Product Code: opc
  • Availability: In Stock
  • £45.00

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