In the Philippines, the 13th Month Pay is not a mere Christmas bonus or a discretionary gift from the employer; it is a mandatory statutory benefit. While Presidential Decree No. 851 (PD 851) originally established this requirement, subsequent jurisprudence and Department of Labor and Employment (DOLE) regulations have clarified how this benefit applies to employees who leave a company before the end of the calendar year.

1. The Mandatory Nature of the Benefit

Under the law, all rank-and-file employees are entitled to a 13th-month pay, provided they have worked for at least one (1) month during the calendar year. This entitlement remains regardless of the nature of their employment (regular, probationary, or fixed-term) or the method by which their wages are paid.

2. Entitlement Upon Resignation or Termination

A common misconception is that an employee forfeits their 13th-month pay if they resign or are terminated before the traditional December payout. This is incorrect.

The Revised Guidelines on the Implementation of the 13th Month Pay Law explicitly state that an employee who has resigned or whose services were terminated at any time before the time for payment of the 13th-month pay is entitled to this benefit in proportion to the length of time they worked during the year.

Resignation: Whether the resignation is voluntary or due to "constructive dismissal," the pro-rated amount must be paid.
Termination for Cause: Even if an employee is dismissed for "Just Causes" (e.g., serious misconduct, willful disobedience, or gross neglect of duties), they are still entitled to their pro-rated 13th-month pay. Because it is an accrued benefit earned through labor already performed, it cannot be waived or forfeited as a penalty.
Termination for Authorized Cause: If the separation is due to retrenchment, redundancy, or closure of business, the 13th-month pay is paid alongside separation pay.

3. Computation of Pro-Rated Pay

The formula for computing the 13th-month pay is straightforward:

(Total Basic Salary Earned during the Calendar Year) / 12 = 13th Month Pay

What is included in "Basic Salary"?

This includes all remunerations or earnings paid by the employer for services rendered.
It does not include allowances and monetary benefits which are not considered or integrated as part of the regular or basic salary, such as:
- Unused vacation and sick leave credits (converted to cash).
- Overtime pay.
- Premium pay (holiday or rest day pay).
- Night shift differential.
- Cost-of-living allowances (COLA).

Note: If these items are integrated into the basic salary by individual or collective agreement, or by established company practice, they may be included in the computation.

4. Time of Payment

For active employees, the 13th-month pay must be paid no later than December 24 of every year.

For resigned or terminated employees, the 13th-month pay is typically released as part of their "Final Pay" or "Backpay." Under DOLE Labor Advisory No. 06, Series of 2020, the final pay must be released within thirty (30) days from the date of separation or termination of employment, unless a more favorable company policy or individual/collective bargaining agreement exists.

5. Tax Ceiling

Under the TRAIN Law (Republic Act No. 10963), the 13th-month pay and other benefits are exempt from income tax up to a maximum of PHP 90,000. Any amount exceeding this threshold is subject to regular income tax. This applies equally to pro-rated payments for separated employees.

6. Non-Devaluation and Non-Diminution of Benefits

Employers cannot substitute the 13th-month pay with non-monetary gifts (such as grocery baskets or company products). Furthermore, if a company has a long-standing practice of including allowances in the 13th-month computation, they cannot suddenly withdraw that practice, as it would violate the principle of Non-Diminution of Benefits under Article 100 of the Labor Code.

7. Remedies for Non-Payment

Failure to pay the 13th-month pay constitutes a money claim labor standard violation. Separated employees who do not receive their pro-rated benefit within the prescribed 30-day window for final pay may file a request for assistance through the Single Entry Approach (SEnA) of the DOLE for mediation, or ultimately, a formal complaint with the National Labor Relations Commission (NLRC).