Diminishing Balance, in the context of a loan, is an interest calculation method where the interest for each payment period is computed based only on the remaining outstanding principal balance. As you pay down your loan, the interest charged per month decreases, or “diminishes,” over time. This is the standard, fair, and universally used method for housing loans in the Philippines.
How the Diminishing Balance Method Works
When you take out a housing loan, your fixed monthly amortization is composed of two parts: a payment towards the principal (the actual amount you borrowed) and a payment for the interest (the cost of borrowing the money).
With the diminishing balance method:
- In the early years of your loan: Your loan balance is high, so a larger portion of your monthly payment goes to paying interest, and a smaller portion goes to reducing the principal.
- As you continue to pay: Your loan balance gets smaller. The interest is now calculated on this smaller balance, so the interest part of your next payment is also smaller.
- In the later years of your loan: Since the interest portion has diminished, a much larger portion of your same fixed monthly payment goes towards paying down the principal, allowing you to pay off your loan faster.
This is the most common and borrower-friendly method for long-term loans.
Diminishing Balance for Pag-IBIG and Bank Housing Loans
It is a crucial fact that both the Pag-IBIG Fund and all major commercial banks in the Philippines use the diminishing balance method (also known as the amortization method) to compute interest for their housing loans. This ensures a fair and transparent computation of your loan over its entire term.
Pag-IBIG Loan Considerations
- How to assume balance in Pag-IBIG? “Assuming a balance” is known as Pasalo. While informal pasalo agreements exist, the only legal way is through a formal Assumption of Mortgage with Pag-IBIG. The new buyer must be an active Pag-IBIG member and must be evaluated to have the capacity to pay the remaining loan balance.
- What happens if I don’t pay my Pag-IBIG loan? Consistent non-payment will lead to your loan being in default. Pag-IBIG will send demand letters and may ultimately initiate the foreclosure process to recover the outstanding loan by selling your property.
Clarifying Related (but Different) Concepts
The PAA list includes terms that sound similar but have very different meanings. It’s important to clarify them.
- How to compute the interest rate? You, the borrower, do not compute the interest rate (the percentage). The rate is given to you by the lender (e.g., 6.5% per annum). The diminishing balance is the method used to calculate the actual interest amount (in pesos) based on that rate and your remaining balance.
- What is diminishing returns in real estate? This is an unrelated economic principle. It states that at a certain point, adding more investment to a property (e.g., renovating a kitchen that is already very good) will yield a lower and lower return on investment.
- What is a 20% diminishing value? This typically refers to depreciation, a concept used for assets like cars or equipment that lose value over time. Real estate in the Philippines generally appreciates (gains value), so this concept does not apply to housing loans.
- What is the principle of balance in real estate? This is an appraisal principle stating that a property’s value is maximized when its components are in balance or harmony (e.g., a ₱20 million mansion in a ₱1 million neighborhood is out of balance). It is unrelated to loan balances.
A Local Perspective in the Philippines
The use of the diminishing balance method for housing loans is a nationwide standard set by the Bangko Sentral ng Pilipinas (BSP) for banks and by the charter of government institutions like the Pag-IBIG Fund.
As of this evening, Wednesday, September 24, 2025, at 9:21 PM, any family here in Balagtas, Bulacan, taking out a housing loan to buy their dream home can be assured that their interest payments will be calculated fairly using this method, whether they borrow from a local BDO branch or the Pag-IBIG Fund.
Practical Tip from an Expert
Because your interest is calculated on your remaining balance, the most powerful way to save money on a long-term loan is to make extra payments that are applied directly to your principal. Even small, consistent extra payments (e.g., an extra ₱1,000 per month) made early in the loan term can drastically reduce your total interest payments over the life of the loan and shave years off your mortgage. Always inform your lender that any extra payment is for “principal reduction.”
Real-World Example
The Reyes family takes out a ₱2,400,000 loan for their home in Balagtas, Bulacan, at a 6% annual interest rate (0.5% per month).
- Month 1:
- Interest Due: ₱2,400,000 x 0.005 = ₱12,000
- If their monthly amortization is ₱15,000, the principal paid is ₱15,000 – ₱12,000 = ₱3,000.
- New Loan Balance: ₱2,400,000 – ₱3,000 = ₱2,397,000
- Month 2:
- Interest Due: ₱2,397,000 x 0.005 = ₱11,985 (The interest has diminished).
- Principal Paid: ₱15,000 – ₱11,985 = ₱3,015.
- New Loan Balance: ₱2,397,000 – ₱3,015 = ₱2,393,985
As you can see, each month the interest portion of their payment gets smaller.
Related Terms
- Amortization: The fixed monthly payment that includes both principal and diminishing interest.
- Principal: The outstanding loan amount on which interest is calculated.
- Interest Rate: The percentage used to calculate the interest payment.
- Loan Balance: The remaining principal, which diminishes over time.
- Pasalo (Assumption of Mortgage): The process of transferring the remaining loan balance to a new buyer.
Internal Links:
- Pag-IBIG: Link to a future or existing article focused on Pag-IBIG housing loans.
Frequently Asked Questions (FAQ)
What is the diminishing balance of a loan?
It is an interest calculation method where interest is charged only on the remaining principal balance. As you pay off the loan, the interest part of your payment gets smaller over time. All housing loans in the Philippines use this method.
How to assume balance in Pag-IBIG?
This is done through a formal “Assumption of Mortgage” process. The new buyer must be a qualified Pag-IBIG member and be approved by the fund to take over the remaining loan balance.
What happens if I don’t pay my Pag-IBIG loan?
If you consistently fail to pay, your loan will go into default, and Pag-IBIG may begin the legal foreclosure process to take possession of and sell your property to recover the loan amount.
