Loan Affordability Calculator
How much you can borrow — checked against both the lender’s limit and your own budget.
| Lender’s ceiling | 18,000,000 |
| Your budget ceiling | 25,000,000 |
| Left after costs and debts | 25,000,000 |
How it works
The question "how much can I borrow" has two answers, and they are rarely the same. One is how much a lender will approve. The other is how much your household budget can actually carry. This computes both and takes the smaller, because that is the real limit.
The lender side uses a debt-to-income ratio: total monthly debt service may not exceed some share of income, commonly 40–50% in Vietnam. Existing loan payments come out of that allowance first.
The budget side is simpler and stricter: income minus living costs minus existing debt is what is left to pay an instalment with. A lender does not know what you spend each month; only you do.
With both ceilings in hand, the smaller one is converted back into a loan size by running the annuity formula in reverse: given a monthly payment, a rate and a term, what is the largest principal that payment can carry.
Finally the deposit is added to give a purchase price. That is the figure to take house-hunting — the seller cares about the total, the lender cares about the borrowed part.
The page names which ceiling is binding. If it is DTI, then raising provable income or clearing an existing loan helps. If it is your budget, only cutting expenses helps — and that is the case to take seriously, because the lender will still approve a loan you cannot live alongside.
Formula
Max payment = min(income × DTI − existing debt, income − expenses − existing debt) → Max loan = PMT × (1 − (1 + r)⁻ⁿ) ÷ r
r is the monthly rate, n the number of months. Purchase price = max loan + deposit. When the two ceilings differ widely, the lower one tells you where the problem actually is.
Worked example
Income 30 million a month, living costs 12 million, 3 million of existing repayments, 40% DTI, 10% a year over 20 years, 500 million deposit:
- DTI ceiling (40% × 30m − 3m)
- 9,000,000 đ
- Budget ceiling (30 − 12 − 3)
- 15,000,000 đ
- Max payment (the lower of the two)
- 9,000,000 đ
- Limited by
- The lender’s DTI rule
- Maximum loan
- 932,621,568 đ
- Purchase price
- 1,432,621,568 đ
Here the lender is binding, not the budget — this borrower has 6 million a month more capacity than the approval allows. Clearing the existing 3 million repayment would lift the ceiling to 12 million and the loan to roughly 1.24 billion.
Frequently asked questions
What DTI should I use?
Vietnamese banks commonly accept 40–50% for a mortgage and less for unsecured lending. If you do not know the bank’s rule, use 40% for a conservative figure — being approved for more than expected is the pleasant surprise.
Should income be gross or net?
Use net take-home, since that is the money that actually services the loan. Note that lenders typically assess provable gross income from payslips, so the ceiling they approve may be higher than the one here.
Why does it ask for living costs?
Because the lender does not know them. A DTI rule looks only at income, so someone earning 30 million and spending 25 million is approved like someone spending 10 million. The budget ceiling is the only part of this that protects you from that.
What counts as existing debt?
Every recurring repayment: car finance, consumer loans, credit-card instalment plans, student loans. Lenders can see these on the credit bureau, so omitting one only misleads you.
How does the deposit change things?
It does not let you borrow more, but it raises the purchase price by exactly its own size. Lenders also typically require 20–30% down, and a lower loan-to-value usually earns a better rate.
Should I take a longer term to borrow more?
A longer term lowers the monthly payment and so raises the ceiling, but total interest rises substantially. Take the figure from here into the loan calculator and compare total interest across terms before deciding.
Is this an approval?
No — it is an estimate from general rules. A real decision also depends on credit history, contract type, length of employment, the valuation of the security and each lender’s policy at the time.