Daily compound interest
Calculate how your capital grows with compound interest and discover how little (real daily compounding differs from the monthly compounding this calculator uses).
Results
Final capital
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Total contributed
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Interest generated
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The final capital is calculated compounding monthly: initial capital × (1 + r)^n, plus the future value of monthly contributions [(1+r)^n - 1] / r, where r is the monthly interest rate and n the number of months.
Year-by-year evolution
| Año | Saldo final | Aportado acumulado | Interés acumulado |
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When should you use this calculator?
"Daily compound interest" means interest is calculated and added to the capital every day instead of every month. This calculator, like most compound interest calculators, compounds monthly (the most common convention in real financial products), but the numerical difference versus real daily compounding is very small, as shown in the example below.
Practical example
With €10,000 initial capital at 5% annual interest over 10 years with no additional contributions, monthly compounding (which this calculator uses) gives a final capital of €16,470.09. Real daily compounding, with the formula capital × (1 + rate/365)^(365×years), would give €16,486.65: only €16.55 more over 10 years, a 0.1% difference on the final capital.
Practical tips
This tiny difference exists because the more frequent the compounding, the sooner the accumulated interest itself starts earning interest — but that effect has diminishing returns: going from annual to monthly compounding makes a bigger difference than going from monthly to daily. That's why, for the vast majority of savings and investment decisions, using this calculator (with monthly compounding) gives a result practically identical to what real daily compounding would give.
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Frequently asked questions
How much does the result change between daily and monthly compounding?
Very little: in this page's example (€10,000 at 5% over 10 years), the difference is only €16.55 on a final capital of over €16,000, roughly 0.1%. Compounding frequency matters far less than the interest rate or time horizon.
Why doesn't this calculator offer daily compounding if the difference is so small?
Because monthly compounding is the standard convention in real financial practice (accounts, deposits, funds), and adding a daily compounding option would complicate the calculator for a numerical difference that's practically insignificant in most cases.
Which financial products actually compound daily?
Some products (certain high-yield savings accounts, some money-market instruments) do calculate and accrue interest daily, but as the example shows, the practical effect on the final result is minimal compared to monthly compounding.
When does compounding frequency actually matter a lot?
It matters more the higher the interest rate and the shorter the period being compared between compoundings (for example, annual vs. monthly makes a bigger difference than monthly vs. daily), but in practice, for long-term saving and investing, the interest rate and time horizon have a far bigger impact on the final result than compounding frequency.