The formula
Annual difference = Annual volume × (Current% − Alternative%) ÷ 100
The relationship is linear, so sensitivity testing is immediate: halve the volume and the difference halves; close half the margin gap and the difference halves. This linearity also means the exercise scales — the same four inputs work for a $200k/year SME and a $50M/year corporate.
Wire fees are held constant on both sides deliberately: at treasury volumes they are noise next to margin. If a candidate provider’s fee structure differs materially (per-conversion flats, subscription tiers), add the annual fee difference to the margin-based result.
How to use this calculator
- 1
Pull your conversion profile
From the last twelve months of statements: count of conversions and average size. Use real history, not intentions.
- 2
Measure your current margin
Sample five recent conversions against same-moment wholesale references (the FX Margin Calculator does each one) and average.
- 3
Obtain an alternative margin
A real quote on your top corridor from a candidate provider — not a rate screen, a quote.
- 4
Read and pressure-test the difference
Rerun with conservative inputs. If the difference survives conservatism, it merits a provider trial.
Concentration analysis: optimise the corridor that matters
Treasury FX volume is rarely uniform — most businesses find 60–80% of conversion volume concentrated in one or two corridors. Run this calculator per corridor rather than on the blended total: a 1.3-point improvement on your dominant USD→NGN flow may be worth more than perfect pricing on five minor pairs combined.
Corridor concentration also strengthens negotiation: providers price predictable, recurring single-corridor volume more aggressively than diffuse flow. Presenting your top corridor’s annual volume with a measured current margin is the strongest opening position a treasurer can take into a pricing conversation.
Beyond margin: structure reduces conversion count
The cheapest conversion is the one that never happens. Multi-currency account structures let receivables in a currency fund payables in the same currency — collections in USD paying USD-invoiced suppliers directly, with only the net imbalance converted. Businesses that move from convert-everything to convert-the-net often cut conversion volume by a third before any rate negotiation.
The sequencing matters: fix the structure first (fewer conversions), then the margin (better-priced conversions). KeyBS Pay Global Business Accounts support the hold-and-net pattern across major and African currencies, with quote-first conversion on the residual — both levers in one structure, availability route-dependent.
Common use cases
Provider review business case
Quantify the annual stake before spending a quarter on an RFP — or to justify skipping one.
Corridor-level optimisation
Rank corridors by potential difference and fix the biggest first.
Netting structure evaluation
Model volume reduction from multi-currency netting by lowering the frequency input.
Board reporting
Turn "our FX seems expensive" into a measured annual figure with a remediation option.
Automate this with the API
Automate rate benchmarking across your conversion calendar with the FX endpoint.
curl "https://keybs.io/api/v1/tools/fx?from=USD&to=ZAR&amount=25000" \ -H "x-api-key: YOUR_FREE_KEY"Free Tools API docs and key registration
Frequently asked questions
Is the calculated difference a promise of savings?
No — it is an indicative difference based entirely on the margins you enter. Real outcomes depend on transaction-by-transaction pricing, market conditions and volumes. Validate with real quotes, then a limited-volume trial, before committing flows. We label every output an estimate for exactly this reason.
How do I measure my current blended margin accurately?
Sample at least five recent conversions across your main corridors. For each, compare the executed rate against a wholesale reference captured at the execution timestamp. Average, weighted by size. Statements plus a reference-rate history source make this a one-hour exercise.
Our bank gives us "preferential corporate rates" — worth checking?
Especially then. Preferential is relative to the bank’s retail margin, not to the market. Corporates measuring their preferential rates frequently find 1.5–2.5% margins on African corridors — far from wholesale. Measurement costs an hour; assumptions cost basis points forever.
Do forwards and rate locks belong in this comparison?
Separately. Locks and forwards manage when you convert and at what certainty; margin is what you pay to convert. A provider with tight margins and rate-lock quoting gives you both, but evaluate the two properties independently. The hedging Academy guide covers the certainty side.
What volume justifies dedicated treasury FX attention?
As a rule of thumb: once annual conversion volume passes ~$500k, a one-point margin difference exceeds $5,000 — more than the effort of measuring and requoting. Below that, batch conversions and simple provider comparison capture most of the value.
What does KeyBS Pay offer treasury teams?
Quote-first FX with disclosed pricing on every conversion (from 1.5%, route-dependent), multi-currency Global Business Accounts for hold-and-net structures, and per-transaction documentation for audit. Request a quote on your dominant corridor and run it through this calculator against your measured baseline.
Corridors, tools and reading for this calculator
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