DNS Propagation Check
Compare a record across multiple public resolvers to check propagation.
DNS Propagation Check queries the same record across different public resolvers at once so you can gauge how far a DNS change has spread across the internet. After switching nameservers or editing an A/MX record, you can watch the “propagating” window where some users see the new value while others still get the old one.
This tool asks two public resolvers — Cloudflare and Google — over DNS over HTTPS and compares the answers side by side. If both resolvers agree, the record is marked consistent (propagated); if they differ, it is still propagating. For a single straightforward lookup, use the DNS Record Lookup tool, and check the delegated nameservers with NS Check.
What propagation means
DNS is a distributed system where countless resolvers cache records for the length of their TTL. Even after you change a value at the authoritative nameserver, any resolver that already cached the old value keeps serving it until that cache expires. This gradual “cache flushing and refilling” is what people call propagation.
How to read the result
- Consistent (propagated): both resolvers return the same set of records — the change has spread widely.
- Inconsistent (propagating): resolvers disagree, so stale caches still linger somewhere.
- Order is ignored; values are normalized (lowercased, trailing dot removed) and compared as a set.
Speeding up propagation
Lower a record's TTL ahead of a change (e.g. 300 seconds) so caches expire faster and propagation shortens. Raise the TTL again once the change settles to reduce query load. Delegation changes to the NS records themselves can take longer because they depend on the parent registry's TTL.
Factors that drive propagation speed
There is no single answer to “how long does propagation take.” The factors below stack up to determine the time you actually experience. Sketching the likely scenario from this table before a change saves you a lot of needless anxiety.
| Factor | Effect on propagation | Rough time |
|---|---|---|
Record TTL | A resolver that cached the old value won't fetch the new one until the TTL expires. The TTL is effectively your worst-case delay. | Up to the TTL value (e.g. 3600s = 1 hour) |
| Resolver caching | Each ISP and public resolver expires its cache and honors TTL differently, so the perceived spread varies from user to user. | Varies per resolver |
| Registrar / NS change | Changing the nameserver delegation itself depends on the parent registry (TLD) TTL, so it takes the longest. | Up to 24–48 hours |
| New record vs change | A brand-new record has no old cached value, so it appears almost instantly. Only editing an existing value runs into stale caches. | New: near-instant / change: up to the TTL |
A worked example
Say you change the A record for www.example.com from 203.0.113.10 to203.0.113.20, and that record had a TTL of 3600 seconds. Right after the change, a user querying for the first time gets the new IP 203.0.113.20 immediately, but a user on a resolver that cached the old value just before the change keeps seeing 203.0.113.10 until the cache expires (up to one hour). In this tool, if Cloudflare returns the new IP while Google returns the old one, the result shows “Inconsistent (propagating)”; once both resolvers converge on the new IP within the hour, it becomes “Consistent (propagated).” That is why lowering the TTL to about 300 seconds before a planned change is the single most effective move.
- Symptom: only some users see the old site/IP → cause: resolvers still hold a cache for the old TTL window → fix: wait out the TTL, and lower the TTL before the next change.
- Symptom: a day after an NS change, some clients still aren't updated → cause: the parent TLD's long TTL → fix: allow up to 48 hours and keep both old and new nameservers serving in parallel.
Frequently asked questions
Only two resolvers — can that tell me global propagation?
It says consistent but my site still shows the old value.
Is my input sent anywhere?
Which record types can I compare?
Related guides
- Why DNS Propagation Is Slow and How to Check ItWhy DNS changes aren't instant (TTL, caching) and how to check and speed up propagation.
- DNS Record Types Explained: A, AAAA, CNAME, MX, TXT, NSWhat each DNS record type does, real value examples, and rules like CNAME restrictions — beginner-friendly.