TTL Countdown
Track TTL expiry at a glance
Estimate cache refresh timing for DNS records.
Type a domain to check TTL countdown results.
Why TTL matters
TTL controls how long resolvers cache DNS answers before refreshing.
What you will see
Current TTL, estimated refresh time, and cache timing hints.
Use cases
Plan DNS changes, monitor cache behavior, and estimate propagation timing.
How TTL countdown is calculated
Resolvers return TTL values with DNS answers. This tool shows the latest TTL and an estimated countdown.
- TTL decreases as the cached record ages.
- A fresh lookup resets TTL to the authoritative value.
- Short TTL values speed up propagation.
When to rely on TTL data
TTL is most useful when planning record changes or verifying cache behavior.
- Compare multiple runs to see TTL drift.
- Use low TTL before migrations.
Common TTL pitfalls
Cached values can differ between resolvers and do not always match authoritative TTLs.
- Resolvers may clamp TTL to a minimum.
- Negative caching can extend error responses.
Error glossary
TTL
Time to Live. The cache lifetime of a DNS response.
Cache refresh
The moment a resolver requests fresh data after TTL expiry.
Negative caching
Caching DNS errors for a short time to reduce repeated failures.
Frequently asked questions
Does a lower TTL speed up propagation?
Yes, lower TTL values allow resolvers to refresh more frequently.
Why does TTL vary between resolvers?
Each resolver caches data independently, so TTL counts down at different times.
What is a good TTL value?
It depends on your needs: lower for fast changes, higher for stability.
Can TTL be clamped?
Some resolvers enforce minimum TTL values for stability.