You can know the open rate of emails by using tracking tools. Email marketing platforms provide open rate metrics. A tracking pixel in your email collects data. This pixel records when a recipient views your email. Total opens divided by delivered emails gives the rate. Multiply the result by 100 to get the percentage. Subject lines affect how many people open your emails. Relevant content keeps recipients engaged. Monitoring trends over time helps improve performance. Low open rates may signal issues with your campaign. You should regularly analyze open rates to refine your email strategy and achieve better results.