Installment Plan Calculator (0% interest)
Walk into any electronics, phone or appliance store in Vietnam and you will see "trả góp 0%" — 0% installment — across the price tags. To a newcomer it sounds like free credit: pay over a year, no interest. In reality, most Vietnamese "0% interest" plans still charge a one-off conversion fee (phí chuyển đổi trả góp) on the financed amount. Because that charge is a fee rather than stated interest, the store advertises "0%" truthfully — but your wallet does not care what the charge is called.
The calculator above rebuilds exactly that deal. You enter the item price, your down payment, the stated interest rate (usually 0%), the term in months, and the one-off conversion-fee percentage. Financed amount = price − down payment; the conversion fee = financed × fee%; your monthly payment is the amortised principal-and-interest plus the fee spread evenly across the term. Crucially, it then solves for the effective annual rate (APR) by bisection — exposing that "0% plus a fee" is not actually free.
Take an illustrative case: a 30.000.000 VND purchase with 6.000.000 VND down (so 24.000.000 VND financed) over 12 months at a stated 0%, but carrying a 5% conversion fee on the financed amount. You pay 2.100.000 VND/month, 31.200.000 VND in total — 1.200.000 VND more than paying cash today. Annualised, that is a loan with an effective APR of about 9.5%/year. One caveat throughout this page: the interest rate and fee in our examples are illustrative assumptions, not quotes. Every store, finance company and promotion has its own schedule — enter the figures from your own contract.
How installment plans are calculated
The five core formulas
| Quantity | Formula |
|---|---|
| Financed amount | price − down payment |
| Conversion fee (one-off) | financed × fee% ÷ 100 |
| Monthly principal + interest | r = 0 → financed ÷ months; r > 0 → financed × r ÷ (1 − (1 + r)⁻ⁿ) |
| Monthly payment | (monthly principal + interest) + fee ÷ months |
| Total paid | down payment + monthly payment × months |
Here r is the monthly rate = annual rate ÷ 12 ÷ 100 and n is the number of months. For a "0%" plan r = 0, so the principal portion is simply the financed amount spread evenly — and the entire cost of credit lives in the conversion fee.
Why "0%" does not mean "free"
A genuine 0% plan charges no conversion fee: in the example above you would pay only 2.000.000 VND/month and exactly 30.000.000 VND in total — the sticker price, nothing more. Add the 5% fee (1.200.000 VND) and the payment rises to 2.100.000 VND/month, with total outlay reaching 31.200.000 VND. That 1.200.000 VND gap over paying cash is the true cost of borrowing, simply wearing a different label.
Converting to a true APR for comparison
The honest way to judge a plan is its effective APR: find the monthly rate i at which the present value of all your monthly payments equals the financed amount, then annualise as APR = ((1 + i)¹² − 1) × 100. The calculator solves this by bisection. In the example, "0% with a 5% fee" is equivalent to a loan at an APR of about 9.5%/year — a single number you can line up against a personal loan or a credit card's APR to see which is genuinely cheaper.
What the model leaves out
The tool assumes no documentation fee, no upfront fee and no loan insurance, that the conversion fee is spread evenly across the term, and that you pay on time every month. Late payments usually carry separate penalties. Every rate and fee here is an illustrative assumption — read your contract and enter every charge you can identify.
Worked example: a 30.000.000 VND purchase, 6.000.000 VND down, 12 months
Illustrative assumptions: price 30.000.000 VND, 6.000.000 VND down (so 24.000.000 VND financed), a stated 0% rate, a 5% conversion fee on the financed amount, a 12-month term.
Paying cash versus buying on installment
| Option | Upfront | Per month | Total paid | Extra vs cash |
|---|---|---|---|---|
| Pay cash | 30.000.000 | 0 | 30.000.000 | — |
| Genuine 0% (no fee) | 6.000.000 | 2.000.000 | 30.000.000 | 0 |
| "0%" with a 5% fee | 6.000.000 | 2.100.000 | 31.200.000 | 1.200.000 |
On the same 30.000.000 VND item, the "0% with a fee" plan costs you an extra 1.200.000 VND versus paying cash. The one-off 1.200.000 VND fee sounds small, but because you only truly "borrow" 24.000.000 VND for 12 months, it is equivalent to a loan at an APR of about 9.5%/year — far from "0%".
What to take away
- "0% interest" and "0% cost" are not the same thing. Always ask: "Is there a conversion fee, and what percent?" before you sign.
- Convert to a true APR to compare. The 9.5%/year here is not cheap — line it up against a personal loan or credit-card APR. FiMo's APR and personal-loan calculators let you compare directly in VND.
- A larger down payment shrinks the financed amount, cutting both the conversion fee (charged on the financed amount) and the monthly payment — the simplest lever if you have cash on hand.
Frequently asked questions
Is "0% installment" in Vietnam actually free?
Usually not. Most "0% interest" (trả góp 0%) plans in Vietnam still charge a one-off conversion fee on the financed amount. In our illustrative example — a 30.000.000 VND purchase, 6.000.000 VND down, 12 months at a 5% fee — you pay 1.200.000 VND more than paying cash, an effective APR of about 9.5%/year. "0% interest" is not the same as "0% cost"; always ask about the conversion fee before signing.
What is the conversion fee charged on?
The conversion fee is typically a percentage of the financed amount (price − down payment), charged once and then spread across the months. Formula: fee = financed × fee%. Example: financing 24.000.000 VND (a 30.000.000 VND price minus 6.000.000 VND down) at 5% is 1.200.000 VND. Split over 12 months, it lifts the payment from 2.000.000 to 2.100.000 VND/month.
What is the monthly payment on a 30 million VND installment over 12 months?
It depends on the down payment and the conversion fee. Under an illustrative assumption — a 30.000.000 VND price, 6.000.000 VND down, "0%" plus a 5% fee over 12 months — you pay 2.100.000 VND/month, totalling 31.200.000 VND. A genuinely fee-free 0% plan would cost only 2.000.000 VND/month. Enter your contract's actual fee into the calculator.
How do I turn a "0% plus fee" plan into a true APR?
Find the monthly rate i at which the present value of all your payments equals the financed amount, then annualise: APR = ((1 + i)¹² − 1) × 100. The calculator solves this by bisection. For the example — 24.000.000 VND financed over 12 months with a 5% fee — the true APR is about 9.5%/year, even though the flyer says "0%".
Does a bigger down payment reduce the cost?
Yes. A larger down payment shrinks the financed amount (price − down payment), which cuts both the conversion fee (charged on the financed amount) and the monthly payment. In the example, financing 24.000.000 VND makes the 5% fee 1.200.000 VND; putting more down lowers that figure. If you have cash on hand, raising the down payment is the simplest way to cut the total cost.
Is store installment different from a credit-card installment?
Yes, in part. Store or finance-company installments usually charge a one-off conversion fee on the financed amount, the mechanism shown above. A credit-card installment (converting one purchase into instalments) also charges a conversion fee, but if you fail to clear the card balance you also incur ordinary credit-card interest, which is typically higher. Use FiMo's credit-card payoff and APR calculators to compare the total cost of each route.
What costs does this calculator leave out?
It models only down payment + (principal and any stated interest) + the conversion fee. It excludes documentation fees, upfront fees, loan insurance, e-wallet collection fees, and late-payment penalties. The interest rate and the 5% fee in the examples are illustrative assumptions only. Add every fee stated in your contract to see the true total cost.