When you change a DNS record, the change takes effect immediately on your domain’s own nameservers. What takes time is everyone else: DNS services like Google’s 8.8.8.8 or your internet provider keep a copy of the old answer for as long as its TTL (time to live) allows, then ask again. So “propagation” is really old copies expiring.

That’s why the cache time matters. If a record had a TTL of one hour before you changed it, some places may show the old answer for up to an hour. Planning a move? Lower the TTL to five minutes a day ahead, make the change, then raise it again.

Some differences are normal and permanent. Big sites and CDNs like Cloudflare give out different addresses depending on where the question comes from, to send visitors to a nearby server. If you’re checking your own change, put the new value in “Value I’m waiting for” to get a clear yes or no from each service.

Most of these DNS services are anycast, meaning they answer from the location nearest to our server. Your own computer and internet provider keep a cache too, so you may see the old answer locally for a while even after every service here has updated. Free use is limited to 50 checks per day.