How long do DNS changes take to update?

A DNS change can appear at the authoritative nameserver within minutes, but cached resolvers may keep the previous answer until its time to live expires. If the old record had a TTL of several hours, some users can receive that answer for the rest of the cached period. The new record’s TTL cannot shorten a cache that already exists.

Nameserver changes can take longer because the registrar and parent zone must publish the new delegation, and resolvers may cache the old one. Providers often describe a broad propagation window, but there is no single moment when every network updates. Different resolvers can show different answers during the transition.

Lower the TTL a day or more before a planned migration when you control the existing zone. After the lower value has had time to take effect, make the destination change. Keep the old server and email service available until the majority of traffic reaches the new system and the previous cache period has passed.

Check the authoritative nameserver first, then compare several public resolvers. If the authoritative answer is wrong, waiting will not fix it; correct the record. If it is right and only some recursive resolvers show the old value, the remaining task is usually to let their valid cache expire.