How to Compute Your Monthly Amortization in the Philippines: A Step-by-Step Guide

You found the perfect condo or house and lot. The price looks doable on paper. But before you sign anything, there's one number that matters more than the sticker price: your monthly amortization. This is the amount you'll actually pay every month for the next 10, 20, or 30 years — and it's what determines whether a property is genuinely affordable or a financial trap waiting to spring.

The good news? Computing your monthly amortization isn't complicated once you know the formula and the few local rules that affect it. In this guide, we'll walk you through exactly how to calculate your payment, the income test lenders use to approve you, and the hidden add-ons that quietly increase your monthly bill.

What Is Amortization, Really?

Amortization is simply the process of paying off a loan through fixed, regular payments over a set period. Each monthly payment is split into two parts: principal (the actual money you borrowed) and interest (the lender's charge for lending it to you).

Here's the part most first-time buyers miss: in the early years, the bulk of your payment goes toward interest, not principal. Only as the years pass does more of each payment chip away at the actual balance. This is why paying extra early in the loan can save you a surprising amount over the full term.

The Amortization Formula

Every bank and Pag-IBIG uses the same standard formula to compute your monthly principal-and-interest payment:

M = P × [ r(1 + r)ⁿ ] ÷ [ (1 + r)ⁿ − 1 ]

Where:

• M = your monthly amortization

• P = the principal (your loan amount, not the property price)

• r = the monthly interest rate (annual rate ÷ 12)

• n = the total number of monthly payments (loan term in years × 12)

Let's make this real with an example.

Worked Example

Say you're buying a ₱3,000,000 condo with a 20% down payment, so you're borrowing ₱2,400,000. Your bank offers a 7% annual rate on a 20-year term.

• P = 2,400,000

• r = 0.07 ÷ 12 = 0.005833

• n = 20 × 12 = 240

Plugging these in gives a monthly amortization of roughly ₱18,600. Over 20 years, you'd pay around ₱4.47 million total — meaning interest alone adds about ₱2.07 million on top of what you borrowed. That gap is exactly why your interest rate and loan term matter so much.

You don't need to do this math by hand every time. Most banks, Pag-IBIG, and property platforms offer free online amortization calculators. But understanding the formula helps you sanity-check their numbers and see how each variable moves your payment.

How Interest Rate and Term Change Your Payment

Two levers control your monthly amortization more than anything else:

1. Interest rate. Even a 1% difference is significant. On a ₱2.4M, 20-year loan, moving from 7% to 8% pushes your monthly payment up by roughly ₱1,400 — over ₱330,000 across the full term.

2. Loan term. A longer term lowers your monthly payment but raises total interest. A shorter term does the opposite. Choose based on cash flow today versus total cost over time.

As of 2026, Pag-IBIG maintains a subsidized 3% per annum rate (fixed for the first 5 years) for socialized housing, with standard rates ranging from about 5.875% to 9.75% depending on your chosen repricing period. Banks like BPI and BDO typically offer fixed rates from around 6.5% to 7.5% for the initial 1-to-5-year period. Pag-IBIG also raised its maximum loanable amount to ₱10 million per borrower in 2026, and loan terms can stretch up to 30 years.

The 35% Rule: Can You Actually Get Approved?

Computing the payment is only half the equation. Lenders also check whether you can afford it using the affordability rule — typically, your monthly amortization should not exceed 35% of your gross monthly income.

So if your monthly amortization works out to ₱18,600, a lender will generally want to see gross monthly income of at least:

₱18,600 ÷ 0.35 ≈ ₱53,150

If you fall short, you have a few options: increase your down payment (which lowers the loan amount), extend the loan term, add a co-borrower to combine incomes, or look for a more affordable property. Running this calculation before you apply saves you from disappointment — and from chasing properties outside your range.

Don't Forget the Hidden Add-Ons

The formula gives you principal and interest. But your actual monthly outflow is often higher because lenders require two insurance policies:

• Mortgage Redemption Insurance (MRI): A life insurance policy that pays off your remaining balance if you pass away before the loan is settled. The premium is usually rolled into your monthly payment and decreases over time as your balance shrinks.

• Fire Insurance: A non-life policy covering the property against fire and similar damage. This is separate from MRI and is typically billed annually.

On top of these, budget for one-time upfront costs when computing affordability: a bank processing fee of roughly 0.5% to 1% of the loan amount, plus transfer taxes, documentary stamp tax, and registration fees. These don't affect your monthly amortization, but they hit your wallet at closing.

Quick Checklist Before You Commit

• Confirm the loan amount (price minus down payment), not the full property price

• Get the exact interest rate and how long it's fixed

• Decide your loan term — balance monthly affordability against total interest

• Run the 35% income test to confirm you'll qualify

• Add MRI and fire insurance to your real monthly budget

• Set aside cash for upfront fees and taxes at closing

The Bottom Line

Your monthly amortization is the single most important number in any property purchase — more telling than the listing price. Master the formula, apply the 35% rule, and account for insurance and fees, and you'll know exactly what you're signing up for before you commit to a decade or more of payments.

Ready to find a property that fits your budget? Browse verified listings and run the numbers on your next home at Listd.ph — your AI-powered partner for buying, selling, and discovering real estate across the Philippines.

Sources: Pag-IBIG Fund 2026 rate announcements (Inquirer Business, Philippine News Agency, Philstar); BPI and BDO published housing loan rates; Pag-IBIG Fund maximum loanable amount update (PNA, May 2026). Figures are illustrative — confirm current rates and terms directly with your lender.