A Run Out Period is an extension past the last day of the plan year to give FSA participants more time to file for reimbursement of claims incurred during the plan year.
Example: If your plan year went from 1/1/2021- 12/31/2021 but you have a run out that ends on 3/1/2022. You have until 3/1/2022 to use up funds by submitting for reimbursement for any expenses that incurred while the plan was active which in this case is 1/1/2021-12/31/2021. This also means you cannot use the funds in your current active plan to pay for services rendered in the previous plan year. If you have a Visa card, do not use the card in this scenario, pay out of pocket and submit for reimbursement.
A Grace Period is an extended period of coverage at the end of every plan year that allows you extra time to incur expenses to use your remaining FSA balance after the plan year closes.
Example: If your plan year went from 1/1/2021- 12/31/2021 but you have a run out that ends 3/14/2022. You can the funds in the plan year that ended 12/31/2021 for expenses that have incurred during that plan year AND during 1/1/2022-3/15/2022.