Hi @shubhamSharma 
If you are looking to create a setup that allows customers to choose between a fixed length or enter a custom length, Easify Product Options app is perfect. It helps you present this option in a clear, professional way and is very easy for shoppers to navigate.
Here’s an example I’ve created so you can see how it works:
Next, in the CHOOSE DEFINED LENGTH option dropdown, you can add all your predefined length values and assign a specific price to each one. Once customers select a value from this dropdown, the product price will automatically update based on your configuration. This dropdown layout is very intuitive, making it easy for customers to compare the options and choose the length that best fits their needs.
If customers need to enter a custom length, select the Dimension option with the value CHOOSE CUSTOM LENGTH, which allows them to input their desired measurement (in mm). In the Basic Settings, you can set the initial values you want; then go to Advanced Settings, enable Add Price, and apply your pricing formula. The app will automatically calculate the cost based on the number of millimeters the customer enters, ensuring accuracy and convenience.
Finally, set up Conditional Logic to control what appears on the product page: when customers choose “Defined Length,” the list of predefined measurements will be displayed; when they select “Custom Length,” the custom input field will appear instead. This creates a smooth and intuitive experience, similar to what you’d find on high-end product customization websites.
Once everything is set up, the length selector will appear directly on the product page with a clean, visually appealing, and easy-to-understand layout. This type of customization greatly boosts customer confidence during the buying process and often leads to higher conversion rates.
The app is extremely easy to use and runs very reliably. If you need help with anything, our support team is always ready to assist you.