Deposit Calculator

Written byOleh Soloninupdated 5 October 2026

Currency

Deposit amount

Rate, % a year

Term, months

Monthly top-up

Compounding

Tax on interest

Result

Closing balance

$10,172.35

Your own money

$10,000.00

Interest earned

$172.35

Effective rate, %

1.72%

Average per month

$14.36

Interest share, %

1.69%

This result is informational only and is not professional advice.

Compounding turns a headline rate into an effective one

Interest on a deposit with monthly, quarterly or annual compounding and optional top-ups, plus the effective annual rate.

The advertised rate and the actual return are different numbers. When interest compounds — is added to the balance and starts earning in its own right — the effective return exceeds the nominal rate. At 4.5 percent compounded monthly, the effective rate is 4.59.

Top-ups behave differently: each dollar paid in works for less time than the opening balance. So a deposit with regular contributions earns less than multiplying the final balance by the rate would suggest.

How to use

Enter the opening amount, the rate from the account terms and the term in months.
If you will add money every month, enter the top-up; it starts earning from the following month.
Choose how the bank credits interest: monthly, quarterly, annually, or once at the end of the term.
Compare accounts on the effective rate rather than the headline rate.

What compounding adds

Without compounding, interest is simple: amount × rate × years, so 10,000 at 4.5 percent earns 450 in a year. With compounding the interest joins the balance each period and earns in turn. Monthly compounding lifts the same year to 459.40, an effective rate of 4.59 percent.

Annual compounding on a one-year term adds nothing, because interest is credited once at the end either way. The difference grows with the rate, the frequency and the length of the term.

4.5% a year for 12 months, top-ups paid at the end of each month. Worked out with this calculator.
Compounding	Effective rate	Interest on 10,000 in a year	Interest on 500 a month
At the end of the term	4.50%	450.00	123.75
Annually	4.50%	450.00	123.75
Quarterly	4.58%	457.65	124.89
Monthly	4.59%	459.40	125.31

Interest by amount and term

Interest grows faster than the term, because with monthly compounding the interest already credited earns interest of its own. The figures below use 4.5% a year, compounded monthly, with no top-ups and before any tax.

Worked out with this calculator.
Deposit	3 months	6 months	12 months	24 months
5,000	56.46	113.56	229.70	469.95
10,000	112.92	227.12	459.40	939.90
25,000	282.31	567.80	1,148.50	2,349.75
50,000	564.61	1,135.60	2,296.99	4,699.51

Why top-ups earn less than you expect

Twelve top-ups of 500 put 6,000 into the account, but without compounding they earn 123.75 in the year rather than 4.5 percent of 6,000; with monthly compounding, 125.31. The first one earns for eleven months and the last for none, so on average the money sits in the account for about half the year.

Banks usually accrue interest by the day, and the day count and crediting dates in the account terms decide the exact figure, so your statement can differ from this equal-month calculation; the gap depends on the balance and the dates. The tax option applies Russian rules and is switched off on this page.

What this calculator shows

The closing balance, your own contributions and the interest earned
The effective annual rate given the compounding frequency
What share of the closing balance is interest

What to keep in mind

Interest accrues monthly at the rate divided by 12 on the running balance and is added at each compounding date; a top-up arrives at the end of a month and earns from the next.
Tax on interest is left out by default. The optional Russian income tax follows Article 214.2 of the Russian Tax Code and does not apply to accounts elsewhere.

FAQs

What is the effective rate?

The return including compounding, annualised. It always exceeds the nominal rate when interest credits more than once a year, and it is the right basis for comparing deposits.

Is deposit interest taxed?

That depends on the country. In Russia, interest above one million roubles times the year's highest key rate is taxed at 13 percent, 15 on the part of the year's investment income above 2.4 million — 160,000 roubles of interest is tax-free in 2026 at a 16 percent key rate, more if the rate is higher on the 1st of a later month — and the calculator can apply that rule if you switch the tax option on.

Compounding or interest paid out?

At the same rate compounding earns more: 10,000 at 4.5% for a year makes 459.40 compounded monthly and 450 paid at the end. If the paid-out account has a higher rate, compare the two on the effective rate.

How much interest does 10,000 earn in a year?

At 4.5% compounded monthly, 459.40; with interest paid once at the end, 450. Over two years the monthly-compounded figure is 939.90, a little more than double, because interest earns interest.

How do I work out deposit interest by hand?

Without compounding, multiply the amount by the rate and by the years: 10,000 × 0.045 × 1 = 450. With monthly compounding use amount × (1 + rate ÷ 12)^months − amount: 10,000 × (1.00375)^12 − 10,000 = 459.40.

How much do I need to deposit to earn 100 a month?

Divide the yearly interest you want by the rate: 1,200 ÷ 0.045 is about 26,667 at 4.5%, before any tax. A lower rate needs a bigger deposit for the same income.

What happens if I withdraw early?

That is set by the account terms, which say what happens to the interest if you take the money out before the end of the term. Check them before you open the account, not when you need the money.

Worked example

10,000 for a year at 4.5 percent

Input: 10,000, 4.5% a year, 12 months, monthly compounding

Output: 10,459.40, interest 459.40, effective rate 4.59%

Note: Without compounding the interest would be exactly 450. The extra 9.40 is interest earning interest.

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