I sell product by the pound. Is there an official way to set up the product or do I have to use the variant option? I would like for the customer to be able to choose the quantity (by the pound, 1-50lbs). When the product is sold it should update the inventory and calculate the shipping label to the correct weight. How do I do this?
Welcome to the Shopify community, yes it is very much possible to setup products in other units including lbs. You can set it up when you are adding products.
Karlie here from the Shopify Guru Team! Great question! To sell your products by the pound, you would simply use your variant feature. Each product can have up to 100 variants. You would set up your variant option as 'Weight' and then your variant values would be pounds. You can follow our step by step guide, here, to see how you can add your variant options and adjust your variant values. If you are looking to customize your variant options more, then you could always look into using an app that would allow you to have more variant options and customizations to your products, like one of these.
If you would like Shopify to keep track of your inventory and help you to avoid selling products that are out of stock, then you could consider using inventory tracking for your products. To enable inventory tracking, you would simply select, 'Track Quantity' from the Inventory section of your product page in your Shopify Admin. This guide will help you set up the inventory tracking feature from within your Shopify Admin.
It sounds like you're wanting to set up your shipping rates depending on weight. This is definitely achievable from within your Shopify Admin, you would just need to make sure that all of your products have weights set up. Your product weights can be set up by going into your Shopify Admin> Products page> Find the product you would like to set up the weight for and click on 'Edit' beside the variant option you want to adjust - the weight option can be found on that page. To have your shipping rates calculate by the weights, you would simply set up weight-based shipping with your products. Be sure to read through our step by step shipping guide, here, to learn about how to set up weight-based shipping in your Shopify Admin.
I hope this has answered your question. If not, or if you have any further questions please let me know. I will be happy to help!