DNS Record Guide and TTL Calculator
Explore the common DNS record types in plain English, turn any TTL value into a human-readable time, and learn how to check DNS yourself with simple commands.
A. DNS record type explorer
A record
Example zone line:
Typical use:
B. TTL calculator
Propagation estimate:
Advice:
C. Check DNS yourself
Replace example.com with your own domain. The dig commands work on Linux and macOS; on Windows, use nslookup or the online checkers.
Good to know
- DNS is a distributed system, so "propagation" really means cached copies expiring one by one. That is why the TTL matters.
- Some ISPs and public resolvers set their own maximum or minimum cache times, so results can vary by location.
- Changing a nameserver (NS) record usually takes longer than other record changes because registries and resolvers cache it heavily.
Frequently Asked Questions (FAQ)
What is a DNS record?
A DNS record is an entry in a zone file that tells the Domain Name System where to send traffic. For example, an A record maps a domain name to an IPv4 address and an MX record points to the server that handles email for the domain.
What is TTL in DNS?
TTL stands for Time To Live. It is measured in seconds and tells DNS resolvers how long they may cache a record before asking for a fresh copy. The calculator on this page converts any TTL value into a readable time.
How long does a DNS change take to take effect?
There is no guaranteed time, but most resolvers will pick up the new value within one TTL period. In practice many changes appear within minutes to a few hours; very long TTLs can delay it.
Should I lower TTL before a website migration?
Yes, it is common practice to lower the TTL (for example to 300 seconds) 24 to 48 hours before a migration so the old cached values expire quickly and the new values spread faster. You can raise it again after the move is stable.