A certificate of insurance (COI) is not the same as an insurance declaration page, although the two have a few things in common. In general, both documents will list the name of your insurance provider and their NAIC number, your policy number, the policy start and end dates and other coverage details — but the main difference is their purpose. In general, a COI is used to provide proof of insurance, while a declaration page is primarily for the policyholder’s reference and goes into greater detail about your coverage levels. While you may use your declaration page as proof of insurance, it contains more sensitive policyholder information, so some homeowners may feel more comfortable using their COI instead.