Markup rate on product and salesby Camptocamp
Add a field on the product form that compute the standard (or theorical) margin based on the current values of sale and cost price present in the product form. We take care of taxe included or excluded.
It will just compute it as follow : (Sale Price without tax - Cost Price) / Sale Price without tax
Remember that this module can be used in conjonction with product_cost_incl_bom to have the cost price computed from the BOM when a product has one.
1) As this module will base his simple computation on sale and cost prices, it suppose you have them both in the same currency (the price type must of the same currency for both of them). Remember this is the default OpenERP configuration (price type of all product price fields are set as the same as the company currency). We don't take care of it cause otherwise we should have added a dependency on sale module.