# Horvath clock

The Horvath clock is a multi-tissue epigenetic age estimator, published by Steve Horvath in 2013. It uses DNA-methylation levels at 353 CpG sites to predict your chronological age, across more than 50 tissues and cell types, with a median error of about 3.6 years. It is the most-cited epigenetic clock, and it is well validated as a predictor of chronological age. But its link to mortality and disease is weaker than that of later, mortality-trained clocks, like GrimAge.

## Sources

- Horvath S. (2013). DNA methylation age of human tissues and cell types. Genome Biology. https://doi.org/10.1186/gb-2013-14-10-r115

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_Canonical: https://longevity-switzerland.com/en/glossary/horvath-clock · Part of Longevity Cities · Updated 2026-06-22_