How to use DNS TTL calculator
Convert a TTL in seconds to readable units and an illustrative cache expiry time. The check runs when you submit the form. Its inputs are processed in this browser.
How the check works
The calculator converts a non-negative integer TTL to days, hours, minutes and seconds. It adds that duration to the current time for an illustrative expiry.
The Overview tab explains the findings. Measured data lets you search individual fields and values, while JSON report shows the complete export. Export JSON to retain a baseline, or print the findings for your own records. Review the report before sharing it: browser characteristics, token claims, and file names can reveal information about your setup.
Read the result in context
The expiry assumes a resolver cached a fresh answer at the displayed time. A real resolver may already have an answer with less lifetime remaining.
Understand the limits
TTL does not reveal global propagation or guarantee every cache expires together. No DNS request is made.
Common questions
Where is the input processed?
In this browser tab. This tool does not submit its input to the site server or a third-party service.
What should I keep with a result?
Record the selected options, browser and time. Review exported values before sharing them. Generated passwords, tokens and HMAC secret keys are excluded from report exports.