Ocmod extension adds ability to set discounts in percents in your opencart 3 store.
Source code: https://github.com/Freeocart/foc-discount-percent
After install, on “Discount”/”Special” tabs of product edit form, you will see the new column “Discount %”
When you set percents, neighbour field (Price) updates with discounted price value. Also when you change base price all discounts will be recalculated automaticaly.
Based on “Percentage discounts” by Jorim van Hove If you looking version 1.5/2.x, please check original module @ here, but pay attention that original module dont update discounts on changing product base price