Compound growth

Daily compound interest calculator

Build multi-currency projections using daily compounding, optional recurring contributions, and reinvestment semantics. Charts and exports arrive in a later pass — run a calculation below to see totals side-by-side as you iterate assumptions.

Principal and currency

Principal & currency

Starting balance and display currency for all amounts.

Commas insert automatically — must be greater than zero.

Projection amounts use this ISO code — no FX conversion in math.

Interest rate
Nominal annual (APR-style) divides the year into 365 equal day periods. APY is converted to an equivalent daily rate for this simulation.

Strictly between 0 and 1000%.

APR is spread evenly across 365 daily periods.

Timeline
Horizon is approximated as years×365 + months×30 + extra days for the daily loop.

Whole years portion of the horizon.

Residual calendar months (0–11).

Adds on top of years and months (~30-day months above).

Contributions
Deposits on a fixed schedule (optional). Amount is per period at the frequency you choose.

Optional — commas insert automatically. Leave blank for no recurring deposits.

How often contribution amounts enter the simulated balance.

Reinvestment
When off, interest accrues on principal and deposits only (simple interest on the growing capital base each day).

On: daily compounding on the full balance.

Runs on the server from your inputs; no account required. Reset clears the form and projection.

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Daily Compound Interest Calculator: Complete Guide

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Frequently Asked Questions