The formula
Annual difference = Volume × (Current margin − Alternative margin) ÷ 100, where Volume = Size × Frequency
The relationship is linear in all three variables: double the volume, frequency or margin gap and the difference doubles. This makes the sensitivity analysis trivial — and makes clear why high-frequency payers (payroll, marketplaces, importers on monthly cycles) have the most at stake.
The comparison isolates margin and deliberately excludes wire fees, which are usually similar in structure across providers and small relative to margin at business volumes. Add them separately if your alternative provider’s fee structure differs materially.
How to use this calculator
- 1
Measure your current margin
Take three recent conversions, compare each rate against a same-moment wholesale reference, and average. The FX Margin Calculator does the per-transaction math.
- 2
Enter your transfer profile
Average size and annual frequency from last year’s statements — real numbers, not estimates.
- 3
Set the alternative margin
From a competing provider’s quote on your corridor — get a real quote rather than a marketing claim.
- 4
Read the annual difference
This is the indicative stake. If it justifies action, run a real side-by-side transfer test before switching volume.
From estimate to evidence: running a provider trial
The calculator motivates the decision; a trial validates it. Send two comparable payments on the same corridor on the same day — one through each provider — and compare landed amounts. One trial beats any number of rate-screen comparisons because it captures everything: margin, fees, deductions and delivery reliability in a single observable outcome.
Keep the trial honest: same amount, same day, same destination account type. Then scale gradually — route a month of volume before committing the year. Provider pricing sometimes degrades after the first impression; measured customers notice.
Where the difference actually comes from
Margin differences between providers reflect liquidity access and business model, not magic. Banks intermediate through correspondent chains and price FX as a profit centre with little transparency pressure. Specialist corridor providers aggregate volume, access wholesale liquidity directly and compete on disclosed pricing. On African corridors this structural gap has historically been widest — and most worth measuring.
KeyBS Pay’s quote-first model is built for this comparison: every quote shows the executable rate, the fee and the committed receive amount, so computing the margin on any KeyBS Pay transaction takes seconds. Fees are from 1.5% and route-dependent — run your corridor through a real quote and let this calculator annualise the result.
Common use cases
Business case for switching
Turn a rate comparison into an annualised figure the CFO can weigh against switching effort.
Bank pricing review
Bring the annual cost of the current margin to the negotiation — banks reprice for customers who quantify.
Budgeting FX costs
Set next year’s FX cost line from volume forecasts and your measured margin rather than guessing.
Corridor prioritisation
Run each corridor separately to find where renegotiation or re-routing pays back fastest.
Automate this with the API
Benchmark a live indicative rate against the rate on your last bank statement.
curl "https://keybs.io/api/v1/tools/fx?from=GBP&to=NGN&amount=20000" \ -H "x-api-key: YOUR_FREE_KEY"Free Tools API docs and key registration
Frequently asked questions
Is the "savings" figure guaranteed?
No — it is an indicative difference based entirely on the margins you enter, and margins vary by transaction, amount and market conditions. Validate with real quotes and a side-by-side trial before relying on the number. That is also why we label every output an estimate.
What margin should I assume for my current bank?
Do not assume — measure. Pull the rate from your last statement, compare it against a wholesale reference from the same day and time, and use that. Businesses that measure often find their real margin is higher than the one they would have guessed.
Do wire fees change the conclusion?
Rarely at business volumes — a $30 fee difference across 24 annual transfers is $720, versus thousands from a one-point margin difference on the same profile. Include them if your frequency is very high or your amounts very small.
How do I get a real alternative margin for my corridor?
Request a quote for a genuine upcoming payment. A quote shows the executable rate for your actual pair and amount — compare it against the wholesale reference at that moment and you have the alternative margin for this calculator.
Does frequency itself affect pricing?
Often — providers tier pricing by monthly volume, and consolidating transfers into larger batches can move you into better tiers while also cutting per-transfer fixed costs. Model batching by adjusting size and frequency together here.
What about rate movement between transfers?
Market movement affects both providers equally and averages out across a year of transfers. The margin gap is structural and persists regardless of direction — which is exactly why it is the number worth optimising.
Corridors, tools and reading for this calculator
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Replace assumptions with a committed quote
Executable rate, disclosed fee, committed receive amount — before you pay anything.
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