What is DNS propagation?
When you change a DNS record, for example pointing your domain at a new web host, the change is live on your authoritative name servers almost immediately. But recursive resolvers around the world (your ISP's, Google's, Cloudflare's and others) keep cached copies of the old answer until its TTL (time to live) expires. "Propagation" is simply the time it takes for those caches to expire and fetch the new value. It typically takes anywhere from a few minutes to the old record's TTL, and up to 48 hours when name servers themselves change, because TLD delegations have long TTLs.
How this checker works
We query the same record at the same moment from six large public resolvers: Cloudflare (1.1.1.1), Google Public DNS (8.8.8.8), AdGuard DNS, NextDNS, DNS.SB and AliDNS. We then highlight which ones agree with the majority answer. These services run anycast networks with many locations, so they reflect what a large share of internet users see. If they all agree on the new value, your change has effectively propagated.
How to speed up DNS propagation
- Lower the TTL in advance. A day before a planned change, reduce the record's TTL to 300 seconds. Once the old TTL has passed, every cache will refresh within five minutes after your change.
- Make the change, verify it with a DNS lookup, then watch this page.
- Flush local caches. On Windows run
ipconfig /flushdns; on macOS runsudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder. Browsers also cache DNS briefly. - Raise the TTL again once everything is stable to reduce query load.
Learn more in What is DNS and how does it work?
Frequently asked questions
Why does propagation take up to 48 hours?
Name server (NS) changes at the registrar are published in the TLD zone, where delegations commonly carry TTLs of one or two days. Ordinary record changes usually finish much faster.
One resolver still shows the old IP. Is something wrong?
Probably not. That resolver location still has a cached copy. Check the TTL column: it shows how many seconds remain before it refreshes.
Can I force a resolver to update?
Some offer it: Cloudflare and Google both have public cache-purge pages for their resolvers.