There are many key performance indicators (KPIs) that can be used to measure the success of a marketing campaign, but here are five common ones:

1. Conversion rate: This is the percentage of visitors to your website or landing page who take a desired action, such as making a purchase or filling out a form. A high conversion rate indicates that your marketing efforts are effective at driving sales or leads.
2. Cost per acquisition (CPA): This is the total cost of acquiring a new customer or sale, divided by the number of new customers or sales. A lower CPA indicates that your marketing efforts are more efficient at generating new business.
3. Return on investment (ROI): This is a measure of the profitability of your marketing campaign. It can be calculated by dividing the total revenue generated by your marketing efforts by the total cost of the campaign. A higher ROI indicates that your marketing efforts are delivering a good return on your investment.
4. Customer lifetime value (CLV): This is a measure of the total value that a customer brings to your business over the course of their relationship with your company. A higher CLV indicates that your marketing efforts are driving long-term customer loyalty.
5. Net promoter score (NPS): This is a measure of customer satisfaction and loyalty. It is calculated by asking customers how likely they are to recommend your business to others, and then categorizing their responses as promoters (very likely to recommend), passives (somewhat likely to recommend), or detractors (not at all likely to recommend). A high NPS indicates that your marketing efforts are creating satisfied and loyal customers.