Quick answer
"Top up with USDT" can describe several balance flows. USDT may convert when a purchase is authorized, convert into a fiat card balance before spending, or fund a separate account from which the card draws. The label does not tell you when conversion happens or which rate applies.
Trace the deposit through account credit, card funding, authorization and settlement. Then include every cost from acquiring USDT to the final merchant debit.
Four common balance models
| Model | Conversion point | Main question |
|---|---|---|
| Shared wallet balance | Authorization or settlement | Which rate and fee apply at purchase? |
| Pre-funded fiat balance | Before spending | Can unused value be moved back? |
| Dedicated crypto card balance | Under provider rules | Is the balance still USDT or already fiat? |
| Collateral or credit | Repayment or liquidation | What creates interest or liquidation risk? |
Match the blockchain first
USDT exists on several networks. Confirm the asset, network, deposit address, minimum, required confirmations and recovery policy on the current deposit screen. An Ethereum address is not automatically valid for Tron.
The BKJ Card page currently names USDT and USDC deposits on Ethereum and Tron. Treat the live deposit screen as the final check for your account.
Identify the receiving balance
After confirmation, record the credited USDT amount, deposit or network charge, receiving wallet and whether a separate transfer or conversion is required. A fiat value shown in the app does not always mean the USDT has already been sold.
Find the conversion and settlement rules
Ask whether USDT converts at authorization, settlement or an earlier manual step. Then check the price source, spread and card foreign-exchange rule. Hotels, car rentals and fuel stations may reserve more than the final bill, so keep enough available balance for the hold.
Calculate the complete cost
Total cost = USDT acquisition + withdrawal or network cost + deposit or funding cost + crypto conversion + card FX + merchant surcharge
| Cost layer | Where to check |
|---|---|
| Source withdrawal and network fee | Sending exchange or wallet |
| Deposit and minimum | Provider deposit screen |
| USDT conversion | Live quote and card terms |
| Card FX and transaction fee | Card fee schedule |
| Merchant surcharge or DCC | Checkout or terminal |
Compare the settled balance reduction for the same purchase, not only the pending amount or annual fee.
Refunds follow the card route
A merchant refund usually returns through the card network to the card account. It is not a new USDT transfer from the merchant. Confirm the credited currency or asset, rate, timing and refundable fees. The BKJ Vietnam QR refund rule is a separate service rule and should not be assumed to govern a virtual-card refund.
Five minute verification
1. Match asset, network and minimum.
2. Record issuer, Visa status and base currency.
3. Save the fee and conversion rules.
4. Send a permitted small test deposit.
5. Make a low-value purchase and compare the settled debit.
The live account offer controls eligibility, network, fees and refund treatment.