TTL (Time to Live) is a number in seconds attached to every DNS record. It tells caching resolvers how long they should store the record before discarding it and querying the authoritative name server for a fresh copy. A TTL of 3600 means the record is cached for 1 hour.
Common TTL Values and Their Uses
| TTL | Duration | Use Case |
|---|---|---|
| 60 | 1 minute | Testing changes — changes propagate almost instantly |
| 300 | 5 minutes | Pre-migration — reduce before making major DNS changes |
| 3600 | 1 hour | Typical for most records — good balance of freshness and load |
| 86400 | 24 hours | Stable records that rarely change (e.g., MX for established domain) |
| 604800 | 7 days | Very stable records — maximum caching, minimum DNS traffic |
How TTL Affects DNS Propagation
When you change a DNS record, the change takes effect immediately at the authoritative server. But cached copies at resolvers worldwide persist until their TTL expires. If your A record has a TTL of 86400 and a resolver cached it 23 hours ago, that resolver will serve the old IP for another hour before it re-queries.
Best Practice: Lower TTL Before Major Changes
- At least 24 hours before a planned change, set the TTL to 300 (5 minutes).
- Wait 24+ hours for the low TTL to propagate and old caches to expire.
- Make your DNS change. Resolvers will pick it up within 5 minutes.
- Once confirmed, raise TTL back to 3600 or higher.
People Also Ask
- What TTL should I use for my domain?
- 3600 seconds (1 hour) is a sensible default for most records. Use lower values (300) when you expect to make changes soon. Use higher values (86400) for stable records to reduce DNS query load and improve reliability through caching.
- Does a lower TTL slow down my website?
- A lower TTL means resolvers query your DNS server more frequently, which slightly increases DNS traffic. It does not directly slow down page load for end users since the lookup itself takes milliseconds. The main risk is higher load on your authoritative DNS server if you have very high traffic.
Related: DNS propagation | DNS records | DNS Lookup