Savings Account Calculator

What does the calculator count.The result is the future capital value after N months when you start with a starting balance and pay a fixed amount every month. Interest accumulates each month at a monthly rate derived from the annual interest rate. Thanks to this, the tool shows how compound interest works in practice and how much faster your capital grows when you add regular payments.

Input parameters. Starting balanceis the amount you start with.Monthly paymentis a fixed payment added at the end of each month.Therate is the annual nominal interest rate.Yearsis the savings period expressed in calendar years. The units next to the fields clearly indicate the currency and time, making it easy to fill out the form quickly.

Monthly rate and number of periods.From the annual interest rate R, we obtain the monthly rate r by dividing R by 12 and by 100. The number of months N is years multiplied by 12. These two values determine the dynamics of capital growth. The higher the rate and the longer the period, the stronger the compound interest effect.

Base formula for future value.The future FV value is the sum of two components: the accrued initial balance and the accrued monthly payments. Verbal description: the start balance increases at a monthly rate throughout the entire period, and each additional payment lasts for a shorter period of time, which is why we use a separate part of the formula. In the utility version, the entry is: FV = balance_start × (1 + r)^N+ monthly_payment × [((1 + r)^N− 1) / r]. If r is very small, the result of some subsidies approaches N × monthly_payment, which corresponds to no interest.

Meaning of the result.FV is the amount you will see on your account after a given period of time, assuming unchanged parameters. Thanks to this, you can compare different payment rates, check the impact of interest rate changes and choose a realistic horizon for your goal, for example a financial cushion or own contribution.

Default values ​​and currencies.In a typical arrangement, the default parameters are a starting balance of PLN 10,000, a monthly payment of PLN 500, an interest rate of 6 percent per year and 3 years. This allows you to immediately see how regular top-ups improve your score relative to your starting balance alone.

Practical notes.Banks may provide promotional rates valid for several months. In this case, the calculator's result will be illustrative, but still useful for comparisons. It's also worth remembering that interest taxes will reduce your final amount. If you want to estimate the after-tax amount, you can use a lower effective rate.

Description of calculation steps in simple language.First, we convert the annual rate into a monthly rate, then we determine the number of months, then we multiply the starting balance by the growth factor and add the value of additional payments converted by the same factor, but taking into account that each payment lasts