Business
Margin, markup, ROI, sales tax, depreciation, and SMB essentials.
All Business calculators
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Understand business numbers
Plain-English explainers paired with the calculators above.
How compound interest actually works
The plain-English version of the formula every finance article quotes — and a feel for why it gets dramatic over decades.
Simple interest vs compound interest
Simple interest grows in a straight line. Compound interest curves upward. Here's when each one shows up.
How a mortgage payment is built
Where every dollar of your monthly payment actually goes — and why the early years are mostly interest.
15-year vs 30-year mortgage
A shorter loan saves enormous interest. A longer loan saves cash flow. The right choice depends on how much room you actually want each month.
How exchange rates actually work
Why the rate on Calcxo, the rate at your bank, and the rate at the airport are all different — and which one you should care about.
Mid-market rate vs bank rate
The mid-market rate is the wholesale price. The bank rate is what you actually get. The gap is how providers make money.