A health FSA may allow participants to carry over unused benefits from a plan year ending in 2020 to a plan year ending in 2021 and from a plan year ending in 2021 to a plan year ending in 2022. A health FSA may extend the grace period for using unused benefits for a plan year ending in 2020 or 2021 to 12 months after the end of the plan year.Irs.Gov Pub969‧Publications.