This extension has been designed to calculate PRODUCT PRICE according to your own sets of rules. This extension supports all kinds of variables(A to Z). You can create any formula and assign it to any product or particular options to calculate product price.
Features:
1: No Core Files are updated(purely ocmod extension).
2: Compatible to 3.x and above versions including Journal 3 Theme.
3: Support Multi Options Formula calculation.
4: Support to enforce minimum square product purchase.
5: You can enforce Round values to be calculated by closing values or variables between curly( { } ) brackets

Introduction price of $50 instead of $80 for limited period of 1 month

Admin Demo
https://skmobile.com.my/custom_formula/admin
username / password: demo / demo
Product Page Demo
https://skmobile.com.my/custom_formula/index.php?route=product/product&product_id=47

Opencart Default Length / Width / Height values will be considered as Unit Prices and whatever would be written in Front End will be multiplied by the prices
These (Length / Width / Height ) are just an option to use. You can create your own formulas without using these 3 default opencart options.
Just check this extension and if it fulfills your requirements or you want some more customization then i am ready to upgrade it . I can also make it's previous / latest versions. If you want to customize it with your Custom Theme then share your FTP.
Free to ask
For any query i am at your doorsteps
Thanks