How to investigate the issue
Markup compares profit with the cost of an item; margin compares profit with the selling price. Suppose a product costs $40 and sells for $60. Its gross profit is $20. The markup is $20 divided by $40, or 50%. The gross margin is $20 divided by $60, or about 33.33%. Confusing these two percentages often leads sellers to set prices too low. A target margin price calculator works backwards from selling costs, fee percentages and the intended contribution margin. Take care with variable payment fees and sales taxes, which can change the correct denominator. Use a consistent currency and cost basis, and remember that promotions may lower margin even if sales increase. The better pricing decision comes from contribution after all variable selling costs rather than markup alone.
Relevant free diagnostic tools
Official reference
Google Merchant Center product data specification. Check current policies and your account for definitive eligibility details.