Let’s Encrypt will reduce the default validity period of its TLS certificates from 90 days to 64 days starting February 10, 2027. The change will apply to all certificates issued or renewed after that date, while previously issued certificates will remain valid until they naturally expire. The nonprofit certificate authority says the move is the first step in a broader transition toward 45-day certificates, which it plans to introduce in 2028.
The shorter certificate lifetime is intended to improve web security by limiting how long a compromised or misissued certificate can remain trusted. It should also make revocation more efficient, because certificates leave circulation sooner and attackers have a smaller window in which to exploit stolen credentials. Let’s Encrypt says the change follows the CA/Browser Forum Baseline Requirements and will eventually be adopted by all publicly trusted certificate authorities.
Website owners and administrators will need to renew certificates more often, but the impact should be manageable for organizations that already use automated renewal. Let’s Encrypt is making 64-day certificates available in its staging environment this week so customers can test their systems before the production change. The organization recommends that all users carry out similar tests to identify renewal failures, outdated scripts, or configuration problems early.
Administrators using clients that support ACME Renewal Info, or ARI, should be prepared automatically because ARI allows Let’s Encrypt to notify the client when a renewal is due. However, organizations with renewal dates hardcoded from a certificate’s expiration date should adjust those settings to approximately two-thirds of the certificate lifetime. Let’s Encrypt says the update will not affect its ACME endpoints, issuance chains, or rate limits, reducing the likelihood of broader service disruption.
The certificate authority will also shorten its authorization reuse period to 10 days next year and to seven hours in 2028. That change is intended to comply with a 2029 reduction in maximum validation reuse periods and to remove the need for CAA rechecking when validation data becomes outdated. With the final 90-day certificate expected to expire on May 11, 2027, businesses should use the transition period to strengthen certificate automation before the industry moves to even shorter lifetimes.