How to handle assembly of new inventory items

Anyway to adjust/add to inventory without a purchase invoice? For example, I buy a large amount of a product. Some of it gets resold as is, some of it get’s added to and modified before selling. Is there a way to take part of my purchase out of one inventory category and put it in another after I’ve modified it for selling?

Here is how you do it, let’s say you are using 10 inventory items of A and 20 inventory items of B to convert into 5 inventory items of C.

Also let’s say inventory item A was $10 purchasing price per unit. inventory item B was $15 purchasing price per unit.

You will simply need to make journal entry with 3 lines.

This journal entry will basically convert 10 inventory items A and 20 inventory items B into 5 inventory items C.

Thanks for your help!

No need to use journal entries for assembling new inventory items. The latest version (14.7.57) contains new tab called Manufacturing orders which streamlines the whole process.