Here’s a practitioner-style explainer focused on the Philippine rules and practice for employees who had two or more employers in the same taxable year and want to pay their annual income tax in installments.

Income Tax Installment Payment for Employees with Multiple Employers (Philippines)

1) Who this applies to

Individuals earning purely compensation income who, at any time during the taxable year, had two or more employers—either concurrently (moonlighting/side jobs) or successively (job change mid-year).
This group is not eligible for “substituted filing.” Even if each employer withheld tax, you must file your own annual return because no single employer can do a complete year-end adjustment on your combined income.

Key consequence: You file BIR Form 1700 (Annual ITR for Individuals Earning Purely Compensation Income Not Qualified for Substituted Filing) for the calendar year, due on or before 15 April of the following year.

2) Why a balance still arises (even though employers withheld)

Withholding on compensation is computed employer-by-employer per payroll period. No one consolidates your total annual compensation across all employers.
The annual tax is computed on your aggregate taxable compensation, after exclusions (e.g., 13th-month/other benefits up to the statutory cap) and after applying the graduated rates in force for the year.
When you sum all compensation and compute the annual tax, the total tax withheld by all employers may be less than the annual tax—creating a balance due (or sometimes an overpayment).

3) Installment payment option (individuals)

If your tax due upon filing (net of withholding and allowable tax credits) exceeds ₱2,000, you may pay in two equal installments:
1. First installment: upon filing your return on or before 15 April.
2. Second installment: on or before 15 October of the same year.
You indicate on BIR Form 1700 that you’re paying by installment. Keep the filed return/acknowledgment as reference for the second payment.

Missed the second installment? The unpaid portion becomes delinquent and may be subject to surcharge, interest, and compromise penalties under the NIRC and its regulations, computed from the applicable due dates.

4) What you must file and attach

BIR Form 1700 for the calendar year.
BIR Form 2316 from each employer you had during the year (ask each employer’s HR/Payroll).
- These show your gross compensation and tax withheld.
- If you had more than one employer at once, you should have multiple 2316s.
If you are also a mixed-income earner (e.g., you also run a business/profession), you instead file BIR Form 1701 (and you are not eligible for substituted filing regardless of employer count). The installment rules for individuals still apply to the net tax due.

5) How to compute—step by step

Gather all BIR Form 2316s. Make sure each shows year-to-date figures.
Consolidate compensation income:
- Add basic pay, taxable allowances, bonuses, and other taxable compensation from all employers.
- Exclude the portion of 13th-month and other benefits that is within the statutory exclusion cap for the year (the cap applies once per individual, across all employers; if the aggregate exceeds the cap, the excess is taxable).
- Minimum wage earners (MWEs): statutory minimum wage pay and certain MWE pay components are exempt—but non-MWE compensation and taxable allowances remain taxable. Apply the rules consistently across employers.
Compute annual income tax using the graduated individual rates applicable for the year. (TRAIN law schedules apply in recent years; use the correct bracket table for that tax year.)
Subtract tax credits:
- Withholding tax on compensation (sum of all 2316 withholding).
- Any other allowable credits (rare for pure compensation).
The result is your annual tax payable (if positive) or overpayment (if negative).
If annual tax payable > ₱2,000, elect installments:
- Pay 50% with the filed return by 15 April.
- Pay 50% by 15 October referencing the same return (keep proof from the first payment).

Simple numerical illustration (purely illustrative)

Employer A taxable comp = ₱700,000; WTC = ₱140,000
Employer B taxable comp = ₱300,000; WTC = ₱40,000
Total taxable comp = ₱1,000,000
Annual tax (apply the correct graduated table for the year) ≈ ₱X
Total WTC = ₱180,000
If Annual tax (₱X) − ₱180,000 = ₱40,000 balance due, you may pay ₱20,000 on/before 15 Apr and ₱20,000 on/before 15 Oct.

(Use the actual rate table for the year of filing; the above is only to show mechanics.)

6) Designating a “main” employer and avoiding under-withholding

If you work for multiple employers concurrently, you may designate a main employer for payroll purposes and treat the others as secondary.
The main employer uses your full personal payroll profile (tax status, exemptions no longer apply post-TRAIN, but dependent details still affect reporting; fringe benefit coverage; 13th-month cap tracking).
Secondary employers typically apply withholding using additional/secondary employment tables or flat computations intended to reduce under-withholding when you have other income elsewhere.
You remain responsible for monitoring the ₱13th-month/other benefits cap and providing accurate declarations so that excesses are taxed somewhere during the year.

7) Filing & payment channels (practical notes)

You can file electronically (e.g., eBIRForms) or manually at the RDO/LT Office that has jurisdiction over your registered TIN (check your registration).
Payment can be made through authorized electronic or over-the-counter channels supported by the BIR at the time of filing; for the second installment, pay by the 15 October deadline and keep the Form 1700 acknowledgment as reference.
If paying the second installment separately, use the facility/form prescribed for installment payments on the original return (your first-installment filing controls the schedule). Keep the bank/e-payment confirmation.

8) What if you overpaid?

If your consolidated computation shows an overpayment, you can opt to carry over the overpayment to the next taxable year or apply for a refund. (Carry-over is commonly simpler for employees without ongoing withholding issues.)

9) Penalties and interest if late

Late filing or late payment can trigger:
- Surcharge (typically 25% of the unpaid tax for failures not involving willful neglect; higher in certain cases).
- Interest on the unpaid amount computed from the statutory due date until paid, at the rate prescribed under the NIRC and its implementing rules in effect for the period.
- Possible compromise penalties per BIR schedules.
These apply separately to the first and second installments if either is unpaid after its due date.

10) Special notes & edge cases

Resigned mid-year then re-hired by another employer: still multiple employers for the year—file 1700. The second employer cannot perform a full year-end adjustment for your prior employer’s pay.
Concurrent public/private employment (e.g., state university + private firm): still multiple employers—file 1700; the public employer’s withholding does not substitute for your private employer’s.
Fringe benefits: For managerial/supervisory employees, fringe benefits tax (FBT) is typically a final tax on the employer, not part of your compensation tax. But perks not covered by FBT may be taxable to you and must be included in your annual consolidation.
Foreign-source salary (while resident in the Philippines) or cross-border remote work: Philippine taxability depends on residency and source rules. If taxable in the Philippines and also withheld abroad, you may explore foreign tax credit rules (outside the narrow “employment-only” scope but relevant to some multiple-employer scenarios).

11) Practical compliance checklist (multiple employers)

☐ Secure all 2316s (one from each employer).
☐ Reconcile: aggregate compensation; track 13th-month/benefit cap; ensure MWE treatment (if applicable) is correct.
☐ Compute annual tax using the correct rate table for the year.
☐ Deduct all WTC and credits to find net tax due.
☐ If > ₱2,000, tick installment and pay 50% by 15 Apr and 50% by 15 Oct.
☐ Keep acknowledgments and payment proofs.
☐ If overpaid, choose carry-over or refund on the return.

Quick FAQs

Q: I had two employers, but my combined withholding exactly equals my annual tax. Do I still need to file? A: Yes. Having multiple employers disqualifies you from substituted filing, so you must file Form 1700 even if no balance is due.

Q: Can I pay in three installments or monthly? A: No. The law allows two equal installments for individuals if the tax due exceeds ₱2,000: by 15 April and 15 October.

Q: What if I pay the entire balance on 15 April? A: That’s fine. The installment option is elective. If you fully pay by the April deadline, there’s no October obligation.

Q: How do I handle the 13th-month/other benefits cap across multiple employers? A: Add all such benefits across all employers. Only the amount up to the cap is excludable from your taxable compensation. Any excess is taxable and should be included in your annual computation.

Important: This is a general guide based on standard Philippine rules and practice. For precise computations (especially where there are cross-border elements, MWEs, or complex benefits), consider consulting a Philippine tax professional or your RDO.