An epoch on Solana is a fixed period of time — approximately 2 to 3 days — during which the set of active validators and their staking weights are fixed. At the end of each epoch, staking rewards are calculated and distributed, and the validator schedule for the next epoch is determined.

Epochs are made up of slots — the basic unit of time on Solana, approximately 400 milliseconds each. An epoch consists of approximately 432,000 slots.

Epoch transitions are significant events on Solana — validator stakes are updated, inflation rewards are distributed, and any pending stake activations or deactivations take effect. Native SOL staking rewards from validator delegation are paid out per epoch.