Skip to content

What is DNS Propagation?

DNS propagation is the period of time it takes for a change to a domain’s DNS records to spread across all the DNS servers on the internet. It’s why, after you update a website’s hosting or point a domain to a new IP address, you might still see the old version of the site for a while—while someone in another location can already see the new one. You’re both right: you’re just looking at different cached versions of the same record.

When a DNS record changes, servers around the world have to let their cached copies expire before fetching the updated information. How long that takes is controlled by a setting called TTL, or Time to Live, a value assigned to each DNS record that tells servers how long to hold onto it before refreshing. Your ISP adds another layer, maintaining its own DNS cache that may not update on schedule regardless of what the TTL says.

In practice, propagation typically completes within a few hours, but can take up to 48–72 hours in some cases. If you’re planning DNS changes, lowering your TTL a few days in advance gives existing caches time to clear out faster once the change goes live.