Here’s a practitioner-grade legal article on Back Pay Eligibility After Eight Months’ Employment (Philippines)—comprehensive but still general information (not legal advice).

Executive takeaways

“Back pay” (a.k.a. final pay/last pay) is everything the employer still owes you at separation: unpaid wages and differentials, pro-rated 13th-month pay, statutory wage premiums, and any convertible leave/benefits under law, policy, CBA, or contract—minus only lawful deductions.
Eight (8) months of service is enough to earn pro-rated 13th-month pay and any other benefits that vest without a 1-year minimum. It is not enough for the statutory Service Incentive Leave (SIL) 5-day benefit (that vests after 1 year of service), nor for statutory retirement pay.
Separation pay is not automatic. It is due mainly if the termination is for authorized causes (redundancy, retrenchment, closure without serious losses, installation of labor-saving devices, or certain disease cases). Resignation and most just-cause dismissals do not carry separation pay (save for narrow equitable exceptions or company/CBA grants).
Employers cannot withhold last pay to force clearance or return of property. They may deduct specific, lawful/authorized amounts (e.g., taxes, SSS/PhilHealth/Pag-IBIG, court/agency-ordered deductions, or written employee-authorized offsets).

What usually makes up back pay (for an 8-month employee)

Unpaid basic salary
- From last payroll cutoff through separation date (including rest days/holidays actually worked and any differentials still unpaid).
Wage premiums (if earned and not yet paid)
- Overtime pay, night shift differential, holiday and rest day premiums, service charge shares (hospitality), and any commissions/incentives that have already vested or become determinable under company plan rules.
Pro-rated 13th-month pay (mandatory)
- Computed as: (Basic salary actually earned for the calendar year ÷ 12).
- No 1-year minimum; eight months’ credited basic pay in the year qualify for an 8/12 share (or exact months/days actually paid).
- Note: Some pay items (e.g., certain allowances/OT/NSD/holiday pay) don’t form part of “basic” for 13th-month computation unless company policy includes them.
Leave conversions
- Statutory SIL (5 days) vests after 1 year continuous service. At 8 months, no SIL is mandated yet.
- Company/CBA leaves (e.g., vacation/sick) convert if the policy says so (some convert unused credits at year-end or upon separation). Check handbook/CBA.
Pro-rated benefits under policy/CBA
- e.g., mid-year/Christmas bonuses (if not purely discretionary), rice/transport allowances that vest by period, perfect attendance awards, etc.
Separation pay (only in specific cases)
- Authorized causes:
  - Redundancy/installation of labor-saving devices: at least one (1) month pay or one (1) month pay per year of service, whichever is higher.
  - Retrenchment/closure not due to serious losses: at least one-half (½) month pay per year of service.
  - Disease not curable within 6 months (with due process): at least one-half (½) month pay per year of service.
- Fraction rule: A service fraction of at least 6 months counts as one (1) whole year. With 8 months of service, you’re treated as 1 year for separation-pay math if you qualify.
- No separation pay for resignation (unless granted by policy/CBA/contract) or just-cause dismissal (narrow equitable exceptions may apply but are rare).
Tax reconciliation and statutory deductions
- Withholding tax recomputed up to separation; any over-withholding may be refunded in the final pay or via your annual filing.
- SSS/PhilHealth/Pag-IBIG contributions and any lawful agency orders continue to be deducted as required by law.

Sample computations (illustrative only)

Assume: Monthly basic = ₱20,000; separation on August 15; no unpaid premiums; no company convertible leave; no authorized-cause termination unless stated.

A) Resignation at 8 months (no separation pay)

Unpaid salary (Aug 1–15): ₱20,000 ÷ 26 working days × 11 working days (example) = ₱8,461.54
13th-month (Jan 1–Aug 15 basic actually earned): say ₱150,000 total basic ÷ 12 = ₱12,500.00
Total back pay (gross) ≈ ₱20,961.54, less lawful deductions.

B) Redundancy at 8 months (authorized cause; separation pay due)

Items above plus separation pay:
- At least 1 month pay per year (fraction ≥6 months counts as 1 year) ⇒ ₱20,000
Total (gross) ≈ ₱40,961.54, less lawful deductions.

C) Retrenchment at 8 months (authorized cause; lower formula)

Separation pay = ½ month pay per year ⇒ ₱10,000
Total (gross) ≈ ₱30,961.54, less lawful deductions.

Notes: • Actual 13th-month depends on basic salary actually earned. • Daily rate divisor (e.g., 26 vs. 22/30) follows company methodology, provided it complies with wage rules and is applied consistently. • Company leaves/benefits may add to the totals if convertible.

Eligibility by mode of separation

Mode of separation	Back pay basics	Separation pay?
Resignation (with proper notice)	Unpaid wages, pro-rated 13th-month, vested/convertible benefits, tax/stats	No, unless policy/CBA/contract grants
End of fixed term (valid project/seasonal/term)	Same as resignation	No, unless authorized-cause situation or policy/CBA grants
Probationary (8 months usually implies regular, unless valid longer probation by law)	Same wage/13th-month entitlements	Only if termination is authorized cause; none for valid failure to qualify (just cause/authorized cause rules apply)
Authorized-cause dismissal (redundancy, retrenchment, closure w/o serious losses, disease)	All final pay items	Yes, per formula above (fraction ≥6 months = 1 year)
Just-cause dismissal (serious misconduct, fraud, etc., with due process)	Unpaid wages + pro-rated 13th-month + vested benefits	Generally none (rare equitable exceptions)

Deductions: what’s lawful and what is not

Lawful/typical

Statutory: withholding tax, SSS, PhilHealth, Pag-IBIG.
Court/agency-ordered deductions (e.g., garnishment).
Employee-authorized deductions in writing (e.g., cash advances, company loans).
Valid negatives under policy/CBA (e.g., prorated uniform cost if there’s a clear, prior written authorization).

Not lawful

Withholding final pay just because clearance is pending or to coerce return of property. The employer should pay what is due and pursue recovery of property/amounts separately or offset only if authorized by law or written consent.
Penalty deductions not grounded on lawful policy/CBA and prior written consent.

Documents you should receive

Payslip/statement of computation of final pay (with itemization).
Certificate of Employment (COE) (on request).
BIR Form 2316 for the period employed with that employer (issued after year-end or upon separation per practice), and clearance document (internal), if applicable.
Separation-pay voucher (if authorized cause).

Timelines & process (practical)

Final pay is generally released within a short, definite period after separation (commonly around a month in many company policies/practices). Delays can be challenged.
If you resigned, render the 30-day notice (or as agreed) unless waived; unused required notice may be set off only if there’s a clear policy/contract allowing it.

Special topics

1) SIL and other leaves at 8 months

Statutory SIL (5 days) is not yet due (vests after 1 year).
Company/CBA leaves follow policy/CBA; many prorate/convert—check rules.

2) Bonuses

Discretionary bonuses (purely ex gratia) are not demandable.
Contractual/Policy/CBA-based bonuses generally prorate on separation if the vesting conditions are met.

3) Training bonds/loans

Recoverable only if validly agreed in writing, reasonable, and not a penalty to restrain employment. Offsetting against final pay requires clear prior consent and compliance with wage-deduction rules.

4) SSS unemployment benefit (separate from back pay)

If separation is involuntary and not due to your fault (e.g., redundancy/retrenchment/closure), you might qualify for SSS unemployment insurance (independent of employer back pay). Eligibility depends on contributions and timing; apply directly with SSS.

Employer due-process reminders (why they matter to your money)

For dismissals, employers must observe notice-and-hearing. Failure can lead to nominal damages even if the cause is valid.
For authorized causes, employers must serve written notices (employee and DOLE) and pay separation pay correctly; non-compliance exposes them to money claims and reinstatement risks.

How to assert your claim (if there’s a dispute)

Write a formal demand: request the itemized final pay and supporting computations; attach IDs/bank details.
Conciliation-mediation: file with the DOLE regional/field office (SEnA route) for a quick, low-cost settlement meeting.
Case filing: if unresolved, pursue the proper forum (e.g., money claims/illegal dismissal with the NLRC Labor Arbiter). Keep all contracts, payslips, time records, emails.

Quick checklists

For employees (8 months’ service)

Copy of appointment/contract and policies/CBA
Latest payslips and time/OT records
Written resignation or termination notice
Request for 13th-month computation and final pay breakdown
Return of company property (documented) to avoid disputes
Request COE and BIR 2316

For employers

Compute unpaid wages and wage premiums to last day
Compute pro-rated 13th-month
Determine leave conversions under policy/CBA
Assess separation pay (if authorized cause; apply fraction rule)
Apply only lawful deductions (with documents)
Release final pay within your policy period; provide computation sheet and certificates

Bottom line

After eight months of employment in the Philippines, a departing worker is definitely entitled to pro-rated 13th-month pay, any earned wages/premiums, and convertible benefits under policy/CBA; SIL is not yet statutorily due; separation pay arises only in defined authorized-cause terminations (with the ≥6-month fraction counting as a full year for the formula). Employers must pay promptly and may deduct only what the law or a valid, written authorization allows. Disputes are resolved quickly via conciliation-mediation and, if needed, the NLRC.

If you want, I can run your facts (monthly rate, last workday, cause of separation, unused leaves, any loans) through a back-pay calculator and give you a clean, itemized worksheet you can attach to a demand or HR ticket.