Polkadot and Kusama utilize eras as their primary method for measuring time periods, with each network having its own unique era duration. The number of eras required to measure a period may vary depending on the topic, but eras serve as the fundamental unit of time measurement for more extended periods in both networks.


An era is a period during which a specific set of active validators exists. Each era has six epochs (or sessions). During the last epoch, the active set of the next era is elected. And after the end of each era, the rewards are calculated and are ready to be distributed to the validators and nominators.

How long does an era last?

An era is 24 hours on Polkadot and 6 hours on Kusama (give or take a few seconds).

Where can I see the phase of the era?

The current phase of the era can be seen at the top right corner of the Polkadot-JS UI Staking Overview page or on the Overview page of the Staking Dashboard.

Polkadot-JS UI:

Staking dashboard (hover the cursor over the graph to display the current era):