Worked guide · bank FX quotes

How do entry quotes, exit quotes and fees change a deposit comparison?

A bank's “exchange rate” is not necessarily one price you can use for both directions. The amount received when buying the deposit currency and the amount received when converting back can differ. Fees may be charged separately, so they should not be hidden inside an advertised deposit rate.

Keep the two conversions separate

Let E be the entry quote in base currency per one comparison-currency unit, and X be the maturity exit quote in the same units. If the base-currency amount is P, the comparison-currency principal is P ÷ E. After simple interest, its maturity amount is multiplied by X to convert back.

comparison principal = P ÷ Ecomparison maturity = (P ÷ E) × (1 + comparison rate × months ÷ 12)converted maturity = comparison maturity × X − explicit fees

This is more transparent than assuming the public mid-market quote is the rate a customer will receive. Record the quote direction, timestamp, channel and any customer tier shown in the bank's app or order preview.

Worked example: a small quote gap nearly removes the advantage

Assume a CNY 100,000 starting amount, a 1.50% CNY deposit, and a 4.00% USD deposit for 12 months. Use an entry quote of 7.20 CNY per USD and an exit quote of 7.10 CNY per USD. Ignore fees and taxes for the moment.

Path	Calculation	Maturity in CNY
Keep CNY	100,000 × (1 + 1.50%)	CNY 101,500.00
Buy USD at entry	100,000 ÷ 7.20 = USD 13,888.89	—
Earn USD interest	13,888.89 × (1 + 4.00%) = USD 14,444.44	—
Sell USD at exit	14,444.44 × 7.10	CNY 102,555.56

Before explicit fees, the USD path is about CNY 1,055.56 higher. With an exit quote of 7.00, it would be about CNY 101,111.11, around CNY 388.89 lower. This illustrates why using the same reference quote at entry and exit can make a comparison look more favorable than the executable round trip.

What the calculator's adjustment field means

The calculator starts with one quote R₀ and converts the principal at that rate. Its optional adjustment S is deducted once from the maturity quote, so the exit quote in its estimate is R₀ − S. For example, entering R₀ = 7.20 and S = 0.10 approximates an exit quote of 7.10.

Unit check: S is an absolute quote difference in base currency per one comparison-currency unit. It is not a percentage and is not an entry-plus-exit fee total. The tool does not reproduce both bank quotes independently. For an exact transaction comparison, use the entry quote and exit quote separately with the formula above.

Keep fees and taxes visible

Record account opening, transfer, wire, intermediary and conversion charges separately.
Check whether a bank's displayed quote already includes a customer-specific margin; do not subtract the same cost twice.
Use the net interest rate only when the bank states the tax deduction clearly; otherwise show tax as a separate estimate.
Use the timestamped rate from the channel where you can actually transact, and note whether the quote expires.

Before treating the result as a decision

Confirm that both offers are available to you, match the balance and term, and use the same interest convention. Check early-withdrawal restrictions and deposit-protection limits. The calculator is an estimate and does not model changing market rates or the rules of structured dual-currency products.

Use the calculator to compare a quote haircut, or read the break-even guide to see how an exchange-rate threshold works. The full method and formulas are also available.