1) The core rule: monthly salary covers the entire month, whether 28, 29, 30, or 31 days

In Philippine labor practice, a monthly-paid employee’s salary is for the whole month, not for a fixed 30-day block. This means that when a month has 31 days, the employee’s monthly salary is not automatically increased just because there is an extra calendar day. The “extra day” is already understood to be included in the concept of a monthly wage.

This is consistent with how monthly-paid compensation is defined and applied in payroll: a monthly rate is a fixed amount for the month, subject only to lawful deductions and adjustments, and subject to additional compensation only when the law or contract requires it (e.g., overtime, holiday pay where applicable, premium pay, or work on rest day).

2) Distinguish the pay scheme: monthly-paid vs daily-paid

Before computing anything, determine the pay scheme:

Monthly-paid: A fixed amount is paid for the month (usually in two semimonthly pays).
Daily-paid: Pay is based on days actually worked (subject to holiday rules).

This article focuses on monthly-paid employees, which include many office staff, professionals, supervisory employees (subject to role and policy), and rank-and-file employees whose compensation is set on a monthly basis.

3) Why “31-day months” become a payroll issue

The controversy usually arises when employers or employees try to “translate” a monthly salary into a daily rate, then apply it to a 31-day month. Problems commonly come from:

Using a 30-day divisor in some computations and assuming a 31st day should be separately paid.
Using a 26-working-day divisor in other computations and mixing working-day and calendar-day logic.
Paying semimonthly (e.g., 15th and 30th/31st) and assuming the second half should be larger in a 31-day month.

Legally and practically, monthly pay is fixed. The 31st day does not create an automatic additional day’s pay unless it triggers a compensable event (work on a holiday/rest day, overtime, etc.) or the contract/CBAs provide otherwise.

4) The legal framework that matters

Philippine wage computation for monthly-paid employees sits within these general rules:

No diminution of benefits: An employer cannot reduce established wage/benefits practices. If an employer has consistently paid an extra amount for 31st days (or used a method that results in higher pay), that practice may become a benefit that cannot be withdrawn unilaterally.
Contract and CBA primacy (as long as compliant with law): If the employment contract, company policy, or CBA promises a method that yields additional pay during 31-day months, that governs.
Correct classification of employees matters for holiday pay and premium pay rules (monthly-paid does not automatically mean exempt from holiday pay; exemption is based on criteria such as being paid by results, managerial status, etc.).
Labor standards on overtime, rest days, and holidays: Additional compensation is not because the month has 31 days, but because work occurred under conditions that legally require premium pay.

5) Common lawful methods of deriving the daily rate for monthly-paid employees

A monthly salary is often converted to a daily rate for specific computations (e.g., absences, tardiness, LWOP, and sometimes leave conversions). There are two commonly encountered divisor concepts in practice:

A. Calendar-day divisor (30 or 365/12 approach)

Many payroll systems use 30 days as a standardized divisor for monthly-paid employees when computing equivalent daily rate. This is a conventional payroll approach for consistency across months and can be acceptable if it is used correctly and consistently for the intended purpose.

A more conceptually accurate calendar approach is:

Daily equivalent = Monthly rate × 12 / 365 (or 366 in leap years) This aligns monthly rate with annualized pay spread across actual days in the year. In practice, however, many companies use simplified divisors.

Important: Whatever divisor is used must be internally consistent and must not result in an unlawful underpayment when applied to legally required premium pays.

B. Working-day divisor (e.g., 261/12, 22, 26, etc.)

Some employers compute a “daily rate” based on working days for internal HR purposes (e.g., leave conversions). This method is not automatically wrong, but it must not be used to evade legally required payments (e.g., holiday pay computations, premium pay, etc.), and it must be aligned with the employee’s work schedule.

Key caution: Mixing working-day divisors with calendar-day logic can lead to disputes—especially if an employer charges absences using one divisor but computes benefits using another in a way that disadvantages employees.

6) The correct practical answer: Do monthly-paid employees get “extra pay” for the 31st day?

Generally, no. A monthly-paid employee does not receive an automatic extra day’s wage in a 31-day month simply because there is an additional calendar day.

However, additional pay may be due if the 31st day is any of the following and the employee works (or is entitled by law even if they do not work, depending on classification):

A regular holiday (and the employee is entitled to holiday pay under the rules applicable to them)
A special non-working day (premium applies if worked; “no work, no pay” is common unless company policy provides pay)
A rest day (premium applies if worked)
A day where the employee works overtime beyond the normal hours (overtime premium applies)
A day covered by a company policy/contract/CBA that grants additional pay

So the legal trigger is not “31 days,” but work under compensable conditions or an entitlement created by law or agreement.

7) Absences and tardiness during 31-day months

Where 31-day months matter most is in deductions.

A. Deductions must follow a fair and consistent formula

For monthly-paid employees, absences are usually deducted based on an equivalent daily rate. Employers must ensure the method:

Is clearly communicated (policy/contract/handbook)
Is consistently applied
Does not produce a result that violates minimum wage, holiday pay rules, or established benefits
Does not effectively penalize an employee beyond the proportionate wage for time not worked (unless there is a lawful basis such as damages or authorized deductions, which are strictly regulated)

B. Avoid “31st-day deduction surprises”

A common employee complaint is: “If my salary is monthly, why is my absence charged as if the month has 30 days?” This is typically answered by the fact that the daily equivalent is a derived figure for payroll mechanics. What makes it lawful is not whether the divisor is 30 or 365/12, but whether:

The employee still receives at least what is due for the month after lawful deductions, and
The method is not applied in a way that results in systematic underpayment or violates established policy/practice.

8) Semimonthly payroll and the “15/16-day half-month” misconception

Monthly-paid employees are often paid twice a month. In 31-day months:

First half may be 15 days; second half may be 16 days (or vice versa depending on cutoffs).
But the semimonthly pay is typically half the monthly rate, not strictly “days in the period × daily rate,” unless the employer explicitly runs payroll that way.

A lawful and common approach:

Semimonthly pay = Monthly rate ÷ 2, subject to adjustments (absences, tardiness, overtime, etc.) within the cutoff.

The 16-day half-month is not automatically higher unless the company’s payroll design computes per day in the cutoff.

9) Holidays in 31-day months: what actually changes

A 31-day month may include holidays (e.g., December often includes holidays). What matters is:

Is it a regular holiday or special non-working day?
Did the employee work, and are they covered by holiday pay rules?
Is the employee monthly-paid rank-and-file (often covered by holiday pay), or exempt (e.g., certain managerial employees)?

For monthly-paid employees who are entitled to holiday pay, the holiday pay is not “because it’s the 31st,” but because the day is a holiday and the law requires specific pay treatment.

10) Rest days and 31st day work

If the 31st falls on an employee’s rest day and the employee is required or allowed to work, the employee may be entitled to rest day premium pay under labor standards. Again, the legal basis is the rest day work, not the 31-day month.

11) Common compliance risks for employers

Employers should be alert to these risks in 31-day months:

Unlawful underpayment arising from inconsistent divisors used to compute daily rate, holiday pay, and deductions.
No diminution exposure if the employer previously paid a “31st day” add-on and then removed it.
Misclassification of employees as “monthly-paid” to imply exemption from holiday pay.
Payroll cutoff confusion, where the 31st is excluded from a cutoff and not properly reflected in attendance, overtime, or premium computations.

12) Best-practice policy language for monthly-paid computation

A strong internal policy typically clarifies:

Monthly salary is a fixed amount covering the entire month.
The company’s standard divisor for daily equivalent rate (and what it is used for).
How absences, tardiness, LWOP, overtime, rest day work, and holiday work are computed.
Cutoff periods and when the 31st day is captured for attendance and premiums.

Clarity prevents disputes. Consistency prevents claims.

13) Practical examples (illustrative only)

Example 1: Fixed monthly salary, no premiums

Monthly salary: ₱30,000
Month: 31 days
Employee works normal schedule, no overtime, no holiday/rest day work. Pay remains ₱30,000 for the month (paid semimonthly per payroll policy).

Example 2: 31st is a rest day and employee works

Monthly salary: ₱30,000
31st falls on rest day; employee works 8 hours. Employee may be entitled to rest day premium based on applicable rules and the employer’s computation method. Additional pay arises because of rest day work, not because the month has 31 days.

Example 3: Employee has 1 day LWOP in a 31-day month

Monthly salary: ₱30,000
1 day absence without pay Deduction depends on the company’s daily equivalent rate policy (e.g., monthly ÷ 30 or annualized divisor). The key legal point is the deduction is proportionate and consistent, and overall pay remains compliant.

14) Employee-side guidance: what to check when you think you are underpaid in a 31-day month

A monthly-paid employee assessing a 31-day month should review:

Employment contract and handbook payroll provisions
Payslip entries for: basic pay, LWOP, tardiness, overtime, holiday premium, rest day premium
Whether the 31st was worked and whether it was a holiday/rest day
Whether the employer changed a long-standing computation method (possible no diminution issue)

15) Bottom line principles

Monthly salary is fixed for the month, regardless of whether the month has 28–31 days.
The 31st day does not automatically create additional basic pay for monthly-paid employees.
Additional pay arises only when labor standards premiums apply (holiday/rest day/overtime/night differential, etc.) or when contract/policy/CBA provides it.
For deductions and conversions, the divisor method must be clear, consistent, and compliant, and must not reduce established benefits or result in underpayment.

16) Quick reference

31-day month + no special work conditions → basic monthly pay unchanged
31st worked on holiday/rest day/overtime → premiums may apply
Absences/tardiness → deductions based on employer’s lawful, consistent daily equivalent method
If employer previously paid more for 31-day months → removal may raise no diminution concerns depending on facts and practice