31 C.F.R. § 29.105 – Computation of time.

(a) For filing documents. In computing the number of days allowed for filing a document, the first day counted is the day after the action or event from which the period begins to run. If the date that ordinarily would be the last day for filing falls on a Saturday, a Sunday, a Federal holiday, or a District holiday, the period runs until the end of the next day that is not a Saturday, a Sunday, or a Federal or a District holiday.
(b) For benefit accrual.
1. (1) Annuity accrues on a daily basis; one-thirtieth of the monthly rate constitutes the daily rate.
2. (2) Annuity does not accrue on the 31st day of any month except that annuity accrues on the 31st day of the initial month if the employee's annuity commences on the 31st day of a 31-day month.
3. (3) For accrual purposes the last day of a 28-day month counts as 3 days and the last day of a 29-day month counts as 2 days.
(c) For counting unused sick leave.
1. (1) For annuity computation purposes—
  1. (i) The service of a participant under the Police and Firefighters Plan who retires on an immediate annuity is increased by the number of days of unused sick leave to the participant's credit under a formal leave system; and
  2. (ii) The service of a participant under the Teachers Plan who retires on an immediate annuity or dies leaving a survivor entitled to an annuity is increased by the number of days of unused sick leave to the participant's credit under a formal leave system.
2. (2) In general, 8 hours of unused sick leave increases total service by 1 day. In cases where more or less than 8 hours of sick leave would be charged for a day's absence, total service is increased by the number of days in the period between the date of separation and the date that the unused sick leave would have expired had the employee used it (except that holidays falling within the period are treated as work days, and no additional leave credit is earned for that period).
3. (3) If an employee's tour of duty changes from part time to full time or full time to part time within 180 days before retirement, the credit for unused sick leave is computed as though no change had occurred.
(d) For counting leave without pay (LWOP) that is creditable service.
1. (1) Under the Police and Firefighters Plan, credit is allowed for no more than 6 months of LWOP in each calendar year.
2. (2)
  1. (i) Under the Teachers Plan, credit is allowed for no more than 6 months of LWOP in each fiscal year.
  2. (ii)
    1. (A) For years prior to fiscal year 1976, each fiscal year started on July 1 and ended on the following June 30.
    2. (B) Fiscal year 1976 started on July 1, 1975, and ended on September 30, 1976.
    3. (C) For years starting in fiscal year 1977, each fiscal year starts on October 1 and ends on the following September 30.