FixMyFX

FixMyFX is a free, no-sign-up calculator for founders who sell or spend in foreign currencies. It lets you enter your annual revenue and annual expenses, and shows roughly what FX fees are costing you per year, followed by a plain-English plan to minimise those costs. The recommended approach is to receive and spend in the same currency, for example by using Wise or Airwallex alongside a local bank account. Where most FX tools compare transfer rates, FixMyFX looks at your whole flow — both income and spending — and the tool runs entirely in your browser, so your numbers are never collected or sent to a server. The problem FixMyFX addresses is what the site calls the "Lazy Tax." Most founders get charged FX fees twice: once on income and once on expenses, which can quietly drain a meaningful share of revenue. The calculator's framing notes that most founders lose 2-5% of revenue to hidden FX fees. FixMyFX is designed for companies that sell to customers abroad, pay suppliers abroad, or both; the site states plainly that if your company, clients and suppliers are all in the same country, you probably don't need this tool. Because the loss is spread across payment processing and bank spreads rather than appearing as a single line item, it is easy to overlook until it is quantified in annual terms. The calculator itself is built around a short set of inputs. You first select where your company is registered, choosing from United Kingdom (GBP), United States (USD), Eurozone (EUR), Australia (AUD), Canada (CAD), the Nordics (DKK/NOK/SEK), New Zealand (NZD), Singapore (SGD), or Other (USD). You then describe how you manage currency: either a Single Currency setup, where you use your local bank for everything in a standard arrangement, or a Multi Currency setup, where you hold funds in multi-currency accounts in an FX-optimised arrangement. Finally you enter your annual revenue and annual expenses in your home currency, along with the percentage of each that is in a foreign currency — for example 60% of revenue or 40% of expenses, with expenses such as SaaS tools, ads and hosting paid in USD given as a typical example. FixMyFX then estimates your fees under two scenarios. The "Current setup" — labelled the Lazy Tax — combines Stripe auto-convert with bank FX. The calculator explains its assumptions inline: Stripe auto-conversion costs 1% (US) or 2% (UK/EU/Rest) on inbound foreign revenue, and a typical bank FX markup of around 3% is applied as a spread on foreign spending and subscriptions. The "FixMyFX setup," labelled Zero Leak, assumes a multi-currency account instead. Direct payout to a matching multi-currency bank account carries a 0% fee; direct spend from matching currency balances also carries a 0% fee; and only the net profit transferred home is converted, at roughly a 0.4% fee using the interbank rate. Both estimates are broken down in the interface under a "How is this calculated?" disclosure so you can see where the numbers come from. The headline output is the Potential Annual Savings, calculated over a 12-month period and framed as money that goes back into your business every year. FixMyFX translates the figure into tangible equivalents so it is easier to grasp — MacBooks Pro, months of Claude Max 20x, Claude Max 5x and Claude Pro subscriptions, and fancy coffees. There is also a toggle to include your savings amount when sharing, and one-click sharing to Twitter/X and LinkedIn, with prefilled text noting that most founders lose 2-5% of revenue to hidden FX fees. If your inputs show you are already operating efficiently, the tool shows a "You are winning!" state instead, explaining that you don't auto-convert revenue (saving 1-2%) and that paying expenses directly from foreign currency balances stops the FX leak completely; in that case it assumes you pay roughly 0.4% conversion fee only on the net profit you bring home. Beyond the number, FixMyFX provides a plain-English, four-step plan for achieving the savings. Step one is to open a multi-currency account, with Wise Business or Airwallex given as examples, matching the currencies your customers pay in (EUR/GBP/USD). Step two is to connect those local bank accounts to Stripe so payouts land directly, avoiding Stripe's 1-2% auto-conversion markup. Step three is to pay foreign expenses — SaaS, ads, overseas contractors — directly from those currency balances with zero FX spread. Step four is to convert only what is left back to your home currency at transparent ~0.4% interbank rates. The four steps are shown alongside the savings estimate and can be expanded in place. A defining characteristic of FixMyFX is that the calculation runs entirely in your browser. The site states that none of your numbers are collected, sent to a server, or tracked, and that no sign-up is required. That makes it practical to enter real revenue and expense figures without worrying about where the data goes. The tool is explicitly presented as an estimator: it provides estimates based on standard publicly available fee structures, does not constitute financial advice, and advises checking your own bank's PDS. The outcome FixMyFX is designed to produce is straightforward: stop the FX leak and keep more of your revenue. By quantifying the annual cost of auto-conversion and bank spreads, it turns an invisible overhead into a specific number you can act on. The estimated savings figure is presented as money that returns to the business each year, and the accompanying plan gives concrete steps rather than general advice. For founders already running a multi-currency setup, the tool provides confirmation that their arrangement is efficient, along with an explanation of why. Practical scenarios include a UK-registered SaaS company billing customers in USD and EUR through Stripe, which can enter its revenue mix to see what auto-conversion is costing. Another is a founder paying for SaaS tools, ads and hosting in USD while earning in GBP, who can model the bank spread on those subscriptions. Founders weighing whether to open a Wise Business or Airwallex account can use it to size the opportunity first. Teams already holding multi-currency balances can run the numbers to confirm they are winning. And founders who want to share the result can post a prefilled message to Twitter/X or LinkedIn with or without their savings amount. FixMyFX is aimed at founders of companies that sell or spend in foreign currencies — particularly those registered in the UK, US, Eurozone, Australia, Canada, the Nordics, New Zealand or Singapore, with an "Other (USD)" option for everywhere else. It is free to use, requires no sign-up, and runs on the web. It was built by Tania Bell, described as a product manager who can code and a former finance manager. The site also offers an optional way to support the builder through a "buy me a coffee" gratuity in USD, GBP or EUR at preset amounts ($5, $15, $25) or a custom amount, explicitly framed as a non-refundable voluntary gratuity rather than a purchase of goods or services. In short, FixMyFX is a free browser-based calculator that shows founders what foreign exchange fees are costing them across both income and expenses, then hands them a clear four-step plan — open matching multi-currency accounts, connect them to Stripe, pay foreign bills directly, and convert only the remainder — to keep that money in the business instead. It is a diagnostic and an action plan on one page, with no sign-up and no data leaving your browser.