Calibre or Vitals Clock?
3 URLs monitored free.
Calibre is an all-in-one performance monitoring product for teams. Its pricing page, checked 16 Oct 2026, lists Starter at $75 a month with real user session monitoring, 5,000 synthetic tests a month, CrUX Core Web Vitals data, unlimited sites and URLs and three seats, plus a 15-day free trial. Team is $150 a month.
Side by side
| Vitals Clock | Calibre Starter | |
|---|---|---|
| Price | $0, $19, $49, $99 | $75 a month |
| Free option | Free plan | 15-day trial |
| URL limit | 3 to 300 by plan | Unlimited sites and URLs |
| Lab tests | PageSpeed Insights, 1 to 4 checks a day | 5,000 synthetic tests a month |
| Real user data | Chrome UX Report | Own RUM plus CrUX |
| Seats | Account-based | 3 seats |
Where Calibre is strong
Calibre's own synthetic agent and RUM give more control and more data than public APIs. Unlimited URLs on every plan is generous if you have a large site and enough test budget.
Where Vitals Clock is strong
A permanent free plan, much lower entry pricing, and a narrow focus on catching regressions without setup.
FAQ
Which is better for a single marketing site?
If you want a full performance toolkit, Calibre. If you want an email when the homepage gets slower, Vitals Clock.