Mortgage Calculator
How to use a mortgage calculator
If you’ve ever sat across from a property agent and watched them punch numbers into a phone, then turn the screen toward you with a monthly figure, you know the feeling. You nod. You have no idea where that number came from. And you’re about to commit to paying it for the next twenty years.
A mortgage calculator fixes that. It won’t find you a house or approve your loan, but it lets you check the math yourself, at home, before anyone is in the room trying to close a sale. Ours has three fields: Loan Amount (₱), Annual Interest Rate (%), and Term (years). Here’s how to fill each one in properly for a Philippine home loan, and how to read what comes out.
Loan amount: what you’re borrowing, not the price of the house
This is the mistake I see most often. People type in the total contract price of the property. That’s not your loan.
Your loan amount is the price minus your down payment (developers usually call it the equity). Banks here commonly lend up to about 80% of the property’s appraised value, so you’re expected to put down around 20%. Pag-IBIG is more generous and can go higher, which is one reason so many first-time buyers go that route.
So for a ₱3,000,000 house with a 20% down payment of ₱600,000, you’d enter ₱2,400,000.
One more thing. The bank bases the loan on the appraised value, and that can come in lower than the selling price. If a unit sells for ₱3 million but appraises at ₱2.8 million, 80% of the appraisal is ₱2.24 million, and you cover the gap in cash. Worth keeping in mind before you spend your savings elsewhere.
Annual interest rate: the one number that changes everything
Enter the yearly rate your lender quotes. The calculator takes care of converting it into a monthly rate.
The catch in the Philippines is that most home loan rates aren’t fixed for the whole loan. You pick a fixing period (1, 3, 5, 10 years and so on), and when it ends, the rate reprices to whatever the market says. Longer fixing periods usually cost more.
For reference, Pag-IBIG’s regular rates in 2026 start at 5.75% for a 1-year fixing period and 6.25% for 3 years, climbing to 9.75% if you lock in for 30 years. There’s also a promo running for applications filed until December 31, 2026: 4.5% fixed for three years on loans up to ₱4.9 million, and 5.75% for bigger loans up to the ₱10 million cap. Qualified socialized housing borrowers under the 4PH program get 3%. Bank rates tend to sit higher, somewhere around 7% to 12% depending on the fixing period.
Rates move, so check with Pag-IBIG or your bank before you rely on any of these. Use the rate you’ve actually been quoted, not the lowest one you saw on a billboard.
Term (years): how long you’ll be paying
This is the length of the loan. Pag-IBIG allows up to 30 years, as long as you’re no older than 70 when the loan ends. Many banks cap it at around 20 to 25 years, and they have their own age limits too.
So a 45-year-old applying with Pag-IBIG can get 25 years at most. Plug in a term you can actually get, or the result is meaningless.
Putting it together
Take that ₱3 million house again. You put 20% down, borrow ₱2,400,000 from a bank at 7%, and choose 20 years.
- Loan Amount: 2,400,000
- Annual Interest Rate: 7
- Term: 20
The calculator gives you a monthly amortization of about ₱18,607. Over 240 payments, you’d hand over roughly ₱4.47 million, which means around ₱2.07 million of it is interest. Yes, nearly as much as you borrowed. That’s normal for a 20-year loan, but it’s still a bit of a gut punch the first time you see it written down.
If you’re curious how the calculator gets there, it uses the standard amortization formula:
P is the loan amount, r is the annual rate divided by 12 (and by 100), and n is the number of monthly payments (years × 12). You don’t need to do this by hand. It’s just nice to know nothing magic is going on.
Change one field at a time and watch what happens
The real value of the calculator is in comparing scenarios. Keep two fields fixed and move the third.
Here’s a ₱3,000,000 loan at 7%, with only the term changing:
| Term | Monthly payment | Total interest |
|---|---|---|
| 15 years | ₱26,965 | ₱1.85 million |
| 20 years | ₱23,259 | ₱2.58 million |
| 25 years | ₱21,203 | ₱3.36 million |
Going from 15 to 25 years saves you about ₱5,800 a month but costs you around ₱1.5 million more in interest. A longer term makes the monthly bill easier to live with. It does not make the house cheaper. Far from it.
Now the same ₱3,000,000 over 20 years, changing only the rate:
| Rate | Monthly payment |
|---|---|
| 7.0% | ₱23,259 |
| 8.5% | ₱26,035 |
| 9.0% | ₱26,992 |
Two percentage points adds almost ₱3,700 a month. That’s a lot of grocery runs.
Stress-test for repricing
Because of repricing, the monthly figure you see today may not be the one you’re paying in year four. So run the numbers twice: once at your current rate, and once at a higher one.
Say you get the Pag-IBIG promo: ₱2,500,000 over 30 years at 4.5%. That comes to about ₱12,667 a month. Now try 6.25%, the regular 3-year rate. You get roughly ₱15,393. The real figure after repricing will be a little lower since you’ll have paid down some principal by then, but it’s close enough to answer the question that matters: could you still pay if the rate went up? If a ₱2,700 jump would break your budget, better to know now.
What the calculator doesn’t include
The number you get is principal and interest only. Your actual monthly payment to the lender is usually higher, because most Philippine home loans also bundle in mortgage redemption insurance (MRI) and fire insurance.
Then there’s everything outside the loan. Transfer fees, documentary stamp tax, registration and notarial fees, and move-in fees if you’re buying from a developer, all due around the time you buy. After that come association dues and your yearly amilyar (real property tax). None of these show up in the calculator, and they add up quickly.
A fairly common approach is to take whatever the calculator says and assume a few thousand pesos more each month once insurance and dues are in.
Check if you’ll actually qualify
Lenders look at how much of your income goes to the loan. Pag-IBIG caps the monthly amortization at 35% of gross monthly income, and banks use similar limits.
A quick way to check: divide your monthly payment by 0.35. For the ₱18,607 example above, you’d need a gross household income of about ₱53,200 a month. If you’re short, you have three levers, the same three fields in the calculator. Borrow less by putting more down, look for a lower rate, or stretch the term (and accept the extra interest that comes with it).
A few habits that help
Use the rate you’ve been quoted in writing. Enter the loan amount after the down payment, never the full price. Try your worst-case rate, not just the promo one. And save a screenshot of each scenario so you can compare offers from Pag-IBIG and two or three banks side by side.
The calculator won’t tell you whether to buy. What it does is take away the guesswork, so when the agent turns that phone toward you, you already know if the number is right.