Daily Compound Interest Calculator

Because interest compounds daily rather than once a year, the interest earned in early days itself starts earning interest before the year is over — that extra compounding within the year pushes the effective yield slightly above the nominal rate you entered. At a 5% nominal annual rate compounded daily, for example, the effective annual rate comes out about 0.13 percentage points above 5% (5.13%), and the gap grows larger at higher nominal rates.

No — Effective Annual Rate is calculated purely from what one year of daily compounding does to the nominal Annual Interest Rate, so it comes out the same whether you're projecting 1 year or 30 years. The Number of Years input only changes how many years of growth get compounded into Future Value and Total Interest Earned, not the annual rate conversion itself.

All three apply the same nominal annual rate, just split into more or fewer pieces per year — daily compounding divides the rate by 365 and applies it 365 times a year, while monthly divides by 12 and applies it 12 times, and annual compounding applies the full rate once. More frequent compounding produces a slightly higher effective yield for the same nominal rate, though the difference between daily and monthly compounding is typically small for realistic interest rates.

Yes — Future Value is Principal multiplied by the same growth factor, (1 + Annual Rate/365)^(365 x Years), regardless of the principal's size, so doubling the principal exactly doubles both Future Value and Total Interest Earned while leaving Effective Annual Rate completely unchanged.