Here’s a thorough, practice-oriented explainer for the Philippine setting. Per your instruction, I’m not using search. Treat this as general legal information to help you prepare documents or brief counsel—not legal advice.

Child Support Demand Letter (Philippines): Everything You Need + Samples

1) Legal backdrop (plain-English)

Who owes support? Both parents—married or not—are obliged to support their child. The duty flows from filiation (being the parent), not from marriage.
What counts as “support”? Necessaries: food, clothing, shelter, medical/dental, education (tuition, school supplies, internet), transportation, and other essentials suited to the family’s social/financial conditions.
How much? Proportional to (a) the child’s needs and (b) each parent’s resources. It can increase/decrease if needs or means change.
When due? Support is demandable from the time a child needs it. Courts typically award support pendente lite from filing of the case; for out-of-court demands, many practitioners anchor arrears from the date of written demand.
Filiation proof matters. For legitimate children: birth certificate naming the father. For illegitimate children: birth certificate naming the father or other proof of acknowledgment (e.g., AAP, admissions). If paternity is disputed, you can still demand support but expect the other parent to insist on proof or testing; court action may be needed.
Barangay conciliation (Katarungang Pambarangay). If you and the other parent reside in the same city/municipality, most support disputes must pass through barangay conciliation/mediation before court—except when covered by VAWC (economic abuse), where barangay/court protection orders may be pursued instead. Check residency/relationship exceptions.
Criminal overlay (economic abuse). Willful refusal to provide support may constitute economic abuse under special laws when it forms part of violence/abuse—consult counsel before threatening criminal action in a letter.
Written settlements. A signed, notarized support agreement is binding as a contract; court approval (e.g., in a custody/support case) makes it directly enforceable by execution if breached. Private MOAs are enforceable via a civil suit if violated.

2) Strategy: sequence that usually works

Evidence file: child’s PSA birth certificate; school billing; medical bills/prescriptions; rent/utility shares; receipts; your income proof; any evidence of the other parent’s resources (employment, business pages, vehicles).
Budget sheet: clear monthly needs; identify which parent already shoulders what.
Friendly demand letter (tone first): propose a figure and sharing; attach budget; give 7–10 business days.
If ignored: send a formal demand through counsel with a deadline and payment channels.
Barangay filing (if applicable) and/or court (support pendente lite + main case). If paternity disputed, include reliefs for DNA/testing and support pendente lite conditioned on proof.
Once paid: issue acknowledgment receipts; keep ledger of payments.

3) How to compute a reasonable ask (practical, not rigid)

List monthly needs (child-only portion):
- Food/groceries; rent share (e.g., 30–50% of rent if dwelling is shared); utilities share (power/water/internet); school tuition/fees; transport; uniforms/books; medical/insurance; communications (phone plan share if needed); childcare.
Net out benefits already provided by either parent (e.g., HMO, school scholarship).
Split by means: if one parent earns ~70% of combined income, a 60–70% share from that parent is often fair.
Propose add-ons: 50–50 split for extraordinary expenses (hospitalization, major dental/orthodontics), subject to prior notice except emergencies.
Escalator: small CPI-linked or 2–5% annual adjustment; or review every 12 months.

4) Tone & content of a strong demand letter

Respectful, child-centered, specific, documented.
Include: identities, filiation, child’s age, brief history of support, itemized monthly needs, your proposed share for each parent, bank/e-wallet details, deadline, and next steps (barangay/court) stated factually.
Attach supporting documents (budget, receipts, birth certificate).
Service: deliver via courier with proof, email, messenger app (screenshot read receipts), or personal service with witness.

5) SAMPLE LETTERS (copy-and-use)

A) Friendly, direct demand (for co-parents who are still communicating)

Subject: Child Support Proposal for [Child’s Name], age [__]

Hi [Name], As we discussed, [Child]’s monthly needs are attached (food, rent share, utilities share, school, transport, medical). The total is ₱[amount]. Based on our incomes, I propose we share it [Parent A __%] / [Parent B __%], so your monthly contribution would be ₱[amount], due every [day] of the month starting [date].

Please send to [bank/e-wallet details] and note “Support – [Child’s Name] [Month]”. For extraordinary expenses (e.g., ER visits, braces), let’s split 50–50 with prior notice when possible.

If you prefer a different split or amount, let’s talk this week and finalize in writing. I’m aiming for something stable for [Child].

Thanks, [Your Name] [Mobile/Email] Attachments: Budget sheet; PSA birth certificate (copy); recent bills/receipts

B) Formal demand through counsel (firmer tone; cites consequences without threats)

[Law Office Letterhead] Date: [____] Via personal service / courier / email

[Parent’s Name] [Address / Email]

Re: Demand for Child Support – [Child’s Name], age [__]

Our client, [Your Name], is the parent of [Child’s Name], as evidenced by the enclosed PSA birth certificate. The child’s reasonable monthly needs total ₱[amount] (Annex “A”). Under Philippine law, both parents are obliged to provide support proportional to their resources and the child’s needs.

Considering your current means known to our client (employment at [Company] / business [details]), we demand that you remit ₱[amount] monthly on or before every [day] of the month, starting [date], to the following account: [bank/e-wallet details]. Extraordinary expenses (medical emergencies, major procedures) shall be for 50–50 sharing upon notice.

Kindly comply within ten (10) days from receipt. Absent compliance, our client will pursue barangay conciliation (if applicable) and court action for support (with support pendente lite), and other appropriate remedies, with prayer for costs and attorney’s fees.

This demand is made without prejudice to other rights and remedies.

Very truly yours, [Lawyer Name] Roll No. [] | IBP [] | PTR [____] Attachments: PSA birth certificate; Budget & computations; Selected receipts

C) Barangay request (if same city/municipality)

To: The Punong Barangay, [Barangay Name] Re: Request for Mediation – Child Support for [Child’s Name]

I, [Your Name], resident of [address], respectfully request mediation with [Other Parent’s Name], resident of [address], for child support.

Facts: We are the parents of [Child’s Name], age [__]. The child’s monthly needs are ₱[amount] (itemized list attached). I propose ₱[amount] monthly from [Other Parent], due every [day] of the month starting [date].

Prayer: Kindly issue summons for mediation/conciliation and assist us in reducing any agreement into a Kasunduan.

Attachments: Child’s PSA birth certificate; budget; receipts; copy of prior demand (if any).

[Your Name & Signature] | Contact No.

6) Support Agreement (MOA) template (private; notarize)

MEMORANDUM OF AGREEMENT ON CHILD SUPPORT Between: [Your Name] and [Other Parent’s Name] (“Parties”), parents of [Child’s Name], born [DOB].

Monthly Support. [Other Parent] shall pay ₱[amount] on or before every [day] of the month starting [date] via [bank/e-wallet details] with reference “Support – [Child] [Month]”.

Scope. Amount covers food, dwelling share, utilities share, education (tuition/fees/supplies/internet), transport, medical/dental, clothing, and other necessaries.

Extraordinary Expenses. The Parties shall share 50–50 in extraordinary, necessary, and reasonable expenses (e.g., ER/hospitalization, orthodontics, major school activities). Prior notice when practicable; proof of expense to be provided.

Adjustments. Parties will review annually every [month] and may adjust by mutual written agreement considering needs and means.

Receipts & Records. [Your Name] will issue acknowledgments for payments received; both Parties will keep records.

Non-waiver. Failure to enforce any term is not a waiver.

Dispute Resolution. Parties shall attempt barangay mediation (if applicable) prior to court.

Effectivity/Separability. Effective upon signing; invalidity of a clause does not affect the rest.

Signed this [date] at [place].

[Your Name] [Other Parent’s Name]

ACKNOWLEDGMENT (Notarial block)

Tip: If you already have or plan to file a court case, consider submitting your MOA for court approval so violations are enforceable by execution.

7) Special situations (how to frame the letter)

Paternity disputed: Attach the PSA birth certificate if it names the father; if not, state basis for filiation (acknowledgments, chats, remittances). Offer DNA testing logistics (cost-sharing or advance by claimant subject to reimbursement if positive). Still propose interim support given the child’s immediate needs.
High-income payor: Be precise and evidence-heavy; add health insurance, tutoring, extracurriculars, and savings/educational plan shares consistent with family station.
Irregular/self-employed income: Propose a base monthly plus a % of variable income (e.g., 10% of net commissions monthly, with statements).
OFW payor: Specify foreign remittance channels, cut-off in PH time, and FX reference (e.g., rate per bank credit).
Existing partial support in kind: Net out what’s actually delivered (e.g., school directly paid) and keep a paper trail to avoid double counting.

8) Documentation & service checklist

PSA birth certificate (copy)
Budget worksheet (with dates and assumptions)
Receipts/bills/tuition statements; medical prescriptions/diagnoses
Your income proof (for proportionality)
Proof of the other parent’s means (if available)
Proof of delivery of the demand (courier receipt, email log, screenshots)
Ledger of payments received (date, amount, channel, reference no.)

9) Do’s & Don’ts

Do: keep the letter child-centric, propose clear numbers, provide payment channels, and set a reasonable deadline. Don’t: harass, defame, contact the other parent’s employer to shame them, or threaten baseless criminal cases. Keep everything you send truthful and sober—your letters may later be read in court.

10) Quick FAQs

Can I claim arrears retroactively? Courts commonly start from filing of the case (or from written demand in practice for negotiations). Better to demand in writing early.
Can we agree to in-kind support? Yes (e.g., direct tuition payment), but keep receipts and ensure time-certain delivery.
What if the other parent pays irregularly? Add late-payment rules (e.g., due date + grace period), and escalate via barangay then court for support pendente lite.
Can support be changed later? Yes—if needs or means change, propose a revised figure or seek modification in court.

11) One-page budget template (drop into your annex)

Food/groceries (child’s share): ₱____
Dwelling (rent/loan share): ₱____
Utilities (power/water/internet share): ₱____
Tuition/fees: ₱____
Books/supplies/uniforms: ₱____
Transport: ₱____
Medical/insurance/medicines: ₱____
Clothing/personal care: ₱____
Childcare/tutoring/extracurriculars: ₱____
TOTAL MONTHLY NEEDS: ₱____
Proposed sharing: Parent A ₱____ ( % ) | Parent B ₱__ ( __% )

Final notes

A good demand letter is polite, precise, provable—and gives the other parent a clear path to comply.
If you want, tell me: (1) your proposed monthly budget, (2) each parent’s approximate income, and (3) whether paternity is contested. I can tailor your letter, MOA, and a barangay filing script to your exact facts.