Loan Comparison Calculator (VND)
When you borrow in Vietnam — a car loan, a renovation loan, an unsecured personal loan — banks rarely quote a single offer. One has a lower headline rate but a longer term; another charges more but clears the debt faster. The trap is to pick the loan with the smallest number on the rate sheet. A lower interest rate is not the same as a cheaper loan. Two figures actually decide the question: the monthly payment, which hits your cash flow every month, and the total interest over the life of the loan, which is the real cost of the money.
The calculator above puts two loans side by side. You enter the amount borrowed, the annual rate and the term in months for each loan, and it returns the level monthly payment and the total interest for both, then flags which loan is lighter month to month and which is cheaper overall. Very often those two answers point in opposite directions: stretching the term lowers the monthly payment but raises the total interest, because you are paying interest on the outstanding balance for more months.
Take the worked example on this page. For the same 500,000,000 VND borrowed, Loan A (an illustrative 11%/year over 60 months) costs about 10.871.212 VND/month, while Loan B (10%/year over 96 months) costs only 7.587.082 VND/month — 3.284.129 VND lighter each month. Yet over the full term, Loan B pays 76.087.185 VND more interest than Loan A. That gap is the price of the longer term, even though Loan B's posted rate is lower.
One caveat applies throughout: every rate on this page is an illustrative assumption, not a quote. Real Vietnamese lending rates vary by bank, product and date, and they commonly float after a promotional period (a reference rate plus a margin). Enter the actual rate from each loan offer to make the comparison realistic.
How the comparison is computed
Level monthly payment
Both loans are modelled as fully amortizing with a fixed monthly payment (principal and interest combined), the standard structure for most bank loans. The payment is:
PMT = P × r ÷ (1 − (1 + r)^−n)
| Symbol | Meaning |
|---|---|
| PMT | Fixed monthly payment |
| P | Amount borrowed (initial principal) |
| r | Monthly rate = annual rate ÷ 12 (as a decimal) |
| n | Number of payments = term in months |
The total of all payments is PMT × n, and total interest = (PMT × n) − P — the money the lender keeps on top of the principal you borrowed.
Two metrics, two different questions
- Monthly payment answers "Can my budget carry this every month?" — an affordability constraint. A longer term shrinks it.
- Total interest answers "What does this loan cost me?" — the price. A higher rate and/or a longer term both push it up.
The tool computes both for each loan, labels the one with the lower total interest as cheaper overall, and the one with the lower monthly payment as lighter month to month. When those disagree, you are looking at a genuine cash-flow-versus-cost trade-off, not a free lunch.
How much does the rate move the needle?
On a fixed term, each extra percentage point of rate adds real money. On 500M borrowed over 60 months at the illustrative assumption, lifting the rate from 11% to 12%/year increases total interest by about 15.060.738 VND. So when two offers share the same term, the lower-rate one is almost always cheaper — the comparison only gets subtle when the terms differ.
What the model leaves out
It assumes a constant rate for the whole term, level amortizing payments, and no fees (origination, loan insurance, prepayment penalty). In Vietnam many loans run a low promotional rate for a few months, then float, so realised interest can differ. To fold fees into a single comparable rate, use FiMo's APR calculator; to see each payment split into principal and interest, use the amortization calculator. Treat the output as a comparison scenario, not a quote.
Worked example: 500M borrowed, two different offers
Illustrative assumptions: the same 500,000,000 VND borrowed, level amortizing payments, a constant rate for the whole term, and no fees.
| Metric | Loan A (11%/yr, 60 mo) | Loan B (10%/yr, 96 mo) |
|---|---|---|
| Monthly payment | 10.871.212 | 7.587.082 |
| Number of payments | 60 months | 96 months |
| Total of payments | 652.272.692 | 728.359.877 |
| Total interest | 152.272.692 | 228.359.877 |
Read the table two ways:
- By monthly cash flow: Loan B is lighter — 7.587.082 VND/month versus 10.871.212 VND for Loan A, saving 3.284.129 VND every month. If your budget is tight, B breathes easier.
- By total cost: Loan A is cheaper. Loan A's total interest is 152.272.692 VND; Loan B's is 228.359.877 VND — a difference of 76.087.185 VND. Even though B's posted rate is lower (10% vs 11%), the extra 36 months of term make it far more expensive in total.
The lesson: ask both questions, do not just read the rate. If you can carry 10.871.212 VND/month and want to pay the least, choose A. If keeping the monthly payment low matters more (to free up cash for other commitments), B is reasonable — and the 76.087.185 VND of extra interest is effectively the price of that flexibility. To roll fees into one comparable number, add FiMo's APR calculator; to watch each payment split between principal and interest, use the amortization calculator.
Frequently asked questions
Is the loan with the lower interest rate always cheaper?
No. Real cost depends on both the rate and the term. In this page's illustrative example, Loan B has the lower rate (10% vs 11%/year) but a longer term (96 vs 60 months), so its total interest (228.359.877 VND) is actually higher than Loan A's (152.272.692 VND) by 76.087.185 VND. Only when two offers share the same term is the lower-rate one guaranteed to be cheaper.
Should I compare on monthly payment or on total interest?
Both — they answer different questions. Monthly payment tells you whether your budget can carry the loan (an affordability constraint); total interest tells you what the loan costs (the price). In the example above, Loan B is 3.284.129 VND/month lighter but costs 76.087.185 VND more in total interest. If you can afford the higher payment, take the loan with lower total interest; if cash flow is tight, you may accept more interest for a lighter month.
How is the monthly payment calculated?
With the level-payment amortization formula: PMT = P × r ÷ (1 − (1 + r)^−n), where P is the amount borrowed, r the monthly rate (= annual rate ÷ 12) and n the number of months. Verifiable: 500,000,000 VND at an illustrative 11%/year (r = 0.009167) over 60 months gives PMT ≈ 10.871.212 VND/month. Total of payments = PMT × 60 = 652.272.692 VND, of which 152.272.692 VND is interest.
Why does a longer term cost more interest?
Because you hold the outstanding balance — and pay interest on it — for more months. A longer term lowers each monthly payment (principal is repaid more slowly), so the balance falls slower and accrued interest piles up. In the example, stretching from 60 to 96 months (even at a lower rate) lifts total interest from 152.272.692 to 228.359.877 VND. A longer term buys a lighter monthly payment at the cost of higher total interest.
How much does one extra percentage point of rate cost?
On a fixed term, a meaningful amount. On 500M borrowed over 60 months at the illustrative assumption, lifting the rate from 11% to 12%/year raises total interest by about 15.060.738 VND. That is why it pays to negotiate the rate and read the floating-rate margin carefully — a single point looks small but compounds across the whole term into real money.
Does this tool include fees and floating rates?
No. The model assumes level amortizing payments, a constant rate for the whole term, and no fees (origination, loan insurance, prepayment penalty). In Vietnam loans often run a promotional rate for a few months, then float on a reference-rate-plus-margin basis, so realised interest can differ. To fold fees into a single comparable rate, use FiMo's APR calculator alongside this comparison.
Are the rates in the examples real Vietnamese bank rates?
No. The 11% and 10%/year used here are illustrative assumptions chosen to make the math easy to follow and verify. Actual VND lending rates differ by bank, product and date. Enter the real rate from each loan offer — the formula behaves identically at any rate.