ABOUT CERO
About Cero
Who makes Cero, and how we write the guides and answers on this website
Cero is an interval timer for iPhone, iPad and Apple Watch, first built in 2017 and made today by Flawless Studio, an independent studio that makes thoughtful apps for everyday life. It’s in 31 languages.
What Cero is for
Cero keeps the time so you can keep your eyes on the workout: HIIT, Tabata, circuits, EMOMs, boxing rounds, running intervals and hybrid race training. It’s a timer, not a coach: it doesn’t tell you what to do, it makes whatever you do easier to follow.
How we write these pages
- Every claim about the app comes from the app itself, as it is today.
- Every claim about training cites a published study or guideline, checked against its source, listed at the end of the page.
- We say when the research is in a particular group, such as trained athletes, and when it’s uncertain.
- We don’t publish ratings, reviews or testimonials.
- The pages are translated into all of Cero’s languages, with the app’s own words for its features.
Contact
Questions, ideas or a mistake on a page? Write to support@cero.app or hi@flawless.studio. Read the terms and privacy policy.
YOUR NEXT SESSION STARTS HERE
Bring the effort.
We’ll keep the time.
Cero is free to download for iPhone, iPad and Apple Watch.
Download Cero
Cero is a timer, not a medical device. If you’re new to hard exercise, are pregnant or have a health condition, check with your doctor first, and stop if you feel unwell.