Personal Loan Calculator (VND)
A personal loan is unsecured credit: the lender advances money against your income and credit history rather than a car or a property, so the rate is higher than a mortgage. If you live and work in Vietnam, you will see these offers everywhere — from banks, from consumer-finance companies, and bundled into "buy now, pay later" deals — and the headline rate is rarely the whole story. This calculator turns three inputs (amount, rate, term in months) into the two numbers that actually matter: your fixed monthly payment and the total interest you will pay over the life of the loan.
The tool uses the standard reducing-balance (amortising) method that reputable banks apply: each month you pay a fixed amount of principal plus interest, and interest is always charged on the outstanding balance, so it shrinks as you repay. For an illustrative 200.000.000 VND loan at 15%/year over 36 months, that works out to 6.933.066 VND/month, with 49.590.365 VND of total interest on top of the 200.000.000 VND you borrowed.
The single most important thing to verify before signing in Vietnam is how interest is calculated. Many sellers quote a flat rate — interest charged on the original principal for the whole term, even on money you have already repaid. The same 200.000.000 VND at a flat 15% costs 90.000.000 VND in interest, which is 40.409.635 VND more than the reducing-balance figure for an identical-looking rate. This article explains the formula, gives a fully reproducible worked example, and lists the questions worth asking. Every rate here is an illustrative assumption, not a current quote from any lender.
How the calculator works
Reducing-balance monthly payment
The tool uses the standard amortising-loan annuity formula:
M = L × r / (1 − (1 + r)^−n)
| Symbol | Meaning |
|---|---|
| M | Fixed monthly payment (principal + interest) |
| L | Loan amount (original principal) |
| r | Monthly rate = annual rate ÷ 12 ÷ 100 |
| n | Number of monthly payments (the term) |
Because interest each month is charged on the remaining balance, the interest portion of M shrinks and the principal portion grows over time, even though M itself never changes. Total repaid = M × n; total interest = (M × n) − L. If the rate is zero, M is simply L ÷ n. A reducing-balance amortisation table is the natural companion view — FiMo's amortization calculator shows the principal/interest split month by month.
Flat rate vs reducing balance — the trap
- Reducing balance: interest is charged on what you still owe. The more you repay, the less interest accrues — fair to the borrower.
- Flat rate: interest = L × annual rate × years, charged on the full original principal for the entire term. In the main example: 200.000.000 × 0.15 × 3 = 90.000.000 VND of interest.
As a rule of thumb, a flat rate of X% is roughly equivalent to a reducing-balance rate of 1.8–1.9 × X%. So "15% flat" is nowhere near as cheap as "15% reducing balance" — always ask which basis the contract uses before comparing percentages.
What the calculator does not include
This tool computes principal and interest only, at the rate you enter. Real personal loans in Vietnam often add:
- Arrangement / processing fees (sometimes 1–2% of the amount, charged upfront).
- Loan insurance, occasionally bundled in, raising the effective cost.
- Early-repayment penalties, commonly 1–5% of the outstanding balance.
These push the true APR above the nominal rate. To fold fees into one comparable number, use FiMo's APR calculator. Treat the output here as the pure principal-and-interest baseline, then add each contract's real fees on top.
Worked example: 200.000.000 VND at 15%/year over 36 months
Illustrative assumptions: a constant 15%/year reducing-balance rate, no fees, no early repayment — exactly the numbers the calculator shows.
Reducing balance vs flat rate
| Interest method | Monthly payment | Total interest | Total repaid |
|---|---|---|---|
| Reducing balance | 6.933.066 | 49.590.365 | 249.590.365 |
| Flat rate 15% | 8.055.556 | 90.000.000 | 290.000.000 |
| Difference | 1.122.490 | 40.409.635 | 40.409.635 |
Same "15%/year" headline, same 200.000.000 VND loan — yet the flat-rate basis costs 40.409.635 VND more in interest, around a fifth of the amount borrowed. That is why the question "is the rate on a reducing balance or the original principal?" matters more than the percentage itself.
A second illustrative loan: 100.000.000 VND at 18%/year over 24 months
| Interest method | Monthly payment | Total interest |
|---|---|---|
| Reducing balance | 4.992.410 | 19.817.845 |
| Flat rate 18% | 5.666.667 | 36.000.000 |
Here a flat 18% adds 16.182.155 VND of interest over the reducing-balance equivalent on a two-year, 100.000.000 VND loan — the gap is larger the higher the rate and the longer the term. The practical takeaways: compare offers on total interest and APR, not the quoted rate; pick the shortest term whose monthly payment fits your budget (ideally keeping total debt obligations under roughly 40% of income — check with FiMo's DTI calculator); and put two quotes side by side with the loan comparison calculator before you commit.
Frequently asked questions
What is a personal (unsecured) loan?
A personal loan is credit advanced without collateral — the lender relies on your income, employment and credit history rather than a car or property. Because there is no asset to seize on default, the lender's risk is higher, so rates run above mortgages and car loans. Amounts and terms are usually smaller and shorter (tens to a few hundred million VND, 12–60 months). In Vietnam these are offered by banks and consumer-finance companies.
What is the monthly payment on a 200.000.000 VND loan at 15%/year over 36 months?
Under an illustrative 15%/year reducing-balance assumption: the payment is 6.933.066 VND/month, total interest 49.590.365 VND, total repaid 249.590.365 VND. If the contract instead uses a flat 15%, the payment rises to 8.055.556 VND/month and total interest to 90.000.000 VND. Enter the rate your lender actually quotes for an accurate figure.
What is the formula for the monthly payment?
M = L × r / (1 − (1 + r)^−n), where L is the amount borrowed, r the monthly rate (annual ÷ 12 ÷ 100) and n the number of months. Verifiable example: L = 200.000.000 VND at 15%/year gives r = 0.0125, n = 36, so M = 6.933.066 VND. Total repaid = M × n = 249.590.365 VND; total interest = 49.590.365 VND.
Reducing balance vs flat rate — which is cheaper?
Reducing balance is almost always cheaper. It charges interest on the outstanding balance, so interest falls as you repay. A flat rate charges interest on the original principal for the whole term. On 200.000.000 VND at "15%/year" over 36 months: reducing balance costs 49.590.365 VND of interest, flat rate costs 90.000.000 VND — 40.409.635 VND more. A flat rate of X% is roughly equivalent to 1.8–1.9 × X% on a reducing balance.
Does a longer term save me money?
No — a longer term lowers the monthly payment but raises total interest. On 200.000.000 VND at an illustrative 15%/year: a 12-month term costs 18.051.662 VND/month (16.619.950 VND interest), while a 60-month term is only 4.757.986 VND/month but 85.479.161 VND interest in total. Choose the shortest term whose payment still fits your budget.
Does this calculator include fees and the true APR?
No — it computes principal and interest only at the rate you enter. Real personal loans often add arrangement/processing fees (1–2% of the amount), bundled loan insurance, and early-repayment penalties (1–5% of the balance). These raise the effective APR above the nominal rate. Use FiMo's APR calculator to convert fees plus rate into one comparable annual percentage, then compare offers on that basis.
Will I be charged a penalty for repaying early?
Usually yes. Many personal-loan contracts charge an early-repayment penalty of roughly 1–5% of the outstanding balance, because paying early deprives the lender of expected interest. If you plan to clear the loan ahead of schedule, a slightly higher-rate loan with no prepayment penalty can be cheaper overall — read the early-repayment clause before signing. This calculator does not model penalties, so add that cost separately.