DNS propagation: why changes take time
Why DNS changes don't take effect instantly, how long propagation takes, and what to do while you wait.
You've made a DNS change — updated your A record, switched nameservers, or added an MX record. But the change doesn't seem to be working yet. Why? This is DNS propagation, and it's completely normal. This guide explains what it is and what to expect.
Quick summary
DNS propagation is the time it takes for a DNS change to spread to all the DNS servers around the world. Most changes take a few minutes to a few hours. In rare cases, it can take up to 48 hours. You can't speed up propagation itself, but you can verify it's working using online tools.
Why DNS changes aren't instant
DNS servers around the world don't pull updates in real time. Instead, they cache (store) DNS records for a set period of time — called the TTL (Time To Live), measured in seconds. Until the cached record expires, a DNS server will continue using the old value even if you've updated it.
For example, if your A record has a TTL of 3600 (one hour), DNS servers that have already looked up your domain will keep using the old IP address for up to one hour before checking for a new value.
Once the TTL expires, they fetch the updated record — and the change takes effect for that server.
How long does propagation take?
| Change type | Typical time | Maximum |
|---|---|---|
| DNS record update (A, CNAME, MX, TXT) | A few minutes to a few hours | Up to 48 hours |
| Nameserver change | A few hours to 24 hours | Up to 48 hours |
Most common DNS record changes propagate to most users within 15 minutes to a few hours. Nameserver changes take longer because they involve the authoritative delegation for your entire domain.
Why some people see the change and others don't
Different DNS servers cache records for different periods. Your ISP's DNS server might have cached the old record. Your visitor's ISP might be checking fresh. This is why you might see the new site immediately while a colleague still sees the old one.
This inconsistency is normal and temporary. It resolves itself once all caches expire.
How to check propagation progress
You can check how far a DNS change has spread using free tools:
- dnschecker.org — Shows what DNS servers in different countries are returning for your domain.
- whatsmydns.net — Similar global propagation check.
- toolbox.googleapps.com/apps/dig/ — Google's dig tool for checking specific record types.
Enter your domain and the record type (A, MX, TXT, etc.) to see what different DNS servers worldwide currently show.
How to speed up propagation
You can't make propagation happen faster once a change is made, but you can reduce the TTL before making the change:
Lower the TTL of the record you're about to change to 300 seconds (5 minutes) — do this at least one full TTL cycle before you make the actual change. For example, if the current TTL is 3600 seconds (1 hour), lower it an hour before you plan to make the change.
Make the DNS change once the low TTL has had time to propagate.
After the change has propagated, restore the TTL to 3600 (1 hour) or 86400 (24 hours) for normal operation.
We often do this automatically before DNS migrations.
Flushing your local DNS cache
Sometimes your own computer has cached the old DNS record. You can flush your local DNS cache to force it to look up fresh records:
Open Command Prompt and run: ipconfig /flushdns
Open Terminal and run: sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder
Type chrome://net-internals/#dns in the address bar, then click Clear host cache.
After flushing, try visiting your site in an incognito/private browser window to test with a fresh lookup.
Common questions
Related guides
- Common DNS problems & fixes
- Pointing your domain to a new site
- Nameservers vs DNS records
- DNS records explained (A, CNAME, MX, TXT)
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