Financial and payroll calculators

where: P = principal (initial amount), r = annual interest rate, t = term in years, I = accrued interest, A = final amount.

Simple interest is calculated only on the initially invested amount (the principal), without taking into account the interest accrued over the period. It is most often used for short-term loans, deposits and some bonds. The calculator shows how much interest you will accumulate over a given period at a fixed interest rate.

where: P = principal, r = annual interest rate, n = number of capitalizations per year (12 for monthly, 4 for quarterly, 1 for annual), t = term in years, A = final amount.

With compound interest, the accrued interest is added to the principal and also starts earning interest — the so-called "interest on interest" effect. The more often interest is capitalized, the faster the investment grows. This calculator is a basic tool for planning long-term investments and savings.

where: CF₀ = the initial investment (with a negative sign), CFₜ = cash flow in period t, n = number of periods. The equation has no analytical solution and is calculated iteratively.

IRR shows the real annual return of an investment, taking into account not only how much money you receive, but also when you receive it. This matters because 1000 received today is worth more than 1000 received in five years — earlier payments can be reinvested and generate additional return. The higher the IRR, the more profitable the investment is for you.

where: CFᵢ = cash flow on date dᵢ, d₀ = the date of the first cash flow. Solved iteratively.

XIRR is the more precise version of IRR — it takes into account the exact date on which you deposit or receive money, not just the order of the payments. This matters because your return depends directly on when money comes in and goes out: a contribution in January works for you longer than a contribution in December. That is why XIRR is the most honest measure of your real annual return when you invest on different dates — for example when regularly buying shares or funds.

where: P = current market price of the bond, C = coupon payment per period, F = face value, n = number of periods to maturity, y = YTM per period. Calculated iteratively.

YTM shows the total annual return an investor would receive by buying a bond at its current market price and holding it to maturity. The indicator accounts for both the coupon payments and the difference between the purchase price and the face value. YTM is the standard by which bonds with different prices, coupons and maturities are compared.

where: r = nominal annual interest rate, n = number of capitalizations per year.

The effective annual rate shows the real return for one year, taking into account how often interest is capitalized. It allows a correct comparison between products with different frequency — for example a deposit with monthly capitalization versus one with annual. The more frequent the capitalization, the higher the effective rate compared to the nominal one.

where: V₀ = initial value, Vf = final value, t = number of years.

CAGR shows the constant annual percentage at which an investment grew from its initial to its final value over a given period. The indicator "smooths out" the fluctuations of individual years and is convenient for comparing different investments. It is suitable for a one-off investment without interim contributions — otherwise use XIRR.

where: CFₜ = cash flow in period t, r = discount rate, C₀ = initial investment, n = number of periods.

NPV measures the present value of all future cash flows of an investment, reduced by the initial outlay. A positive NPV means the project creates value at the chosen discount rate, a negative one — that it destroys value. The indicator is closely related to IRR: IRR is the discount rate at which NPV = 0.

where: PMT = regular contribution per period, r = annual interest rate, n = number of contributions/capitalizations per year, t = term in years, FV = future value.

This formula calculates the amount you will accumulate if you regularly deposit a fixed contribution (for example every month) with compound interest. It is the basis of calculators for savings plans, pension contributions and investing at equal intervals. It clearly shows how disciplined regular saving is multiplied by the effect of compound interest.

where: P = loan amount (principal), i = monthly interest rate (annual rate ÷ 12), n = number of monthly payments, M = monthly payment. The interest part of payment k is Iₖ = Bₖ₋₁ · i, the principal part is Pₖ = M − Iₖ, and the remaining balance is Bₖ = Bₖ₋₁ − Pₖ. Total interest paid over the term is M · n − P.

The loan calculator computes the monthly payment on a loan with equal (annuity) payments — mortgage, consumer or business loan. The amortization schedule shows, for each payment, how much goes to interest and how much repays principal: at the start interest dominates, and over time the principal share grows. The early repayment simulation clearly shows how an extra payment today shortens the term and saves years of interest.

Note: the calculation assumes a fixed rate and equal payments. A real offer includes fees and insurance, reflected in the APR (annual percentage rate of charge).

where: P = deposit amount, r = annual interest rate, n = number of interest payments per year, t = term in years, A = amount at maturity. The first formula applies with capitalization, the second without (interest paid to another account).

The deposit calculator shows the amount you will receive at maturity of a bank deposit based on the amount, term and interest rate. The key setting is whether interest is capitalized (added to the principal, also earning interest) or paid out periodically — over long terms the difference is noticeable.

Important for Bulgaria: since 1 April 2022, interest on deposits of local individuals in banks in Bulgaria and the EU/EEA is not taxed, so the amount shown is final; tax is due only on interest from banks outside the EU/EEA.

where: A₀ = today's amount, π = average annual inflation, t = number of years, CPI = consumer price index (NSI), r_nom = nominal return, r_real = real return after inflation.

The inflation calculator shows how inflation eats away the purchasing power of money — it acts like compound interest in reverse. In one direction it calculates what today's money will really be worth in years, and in the other — what amount will be needed in the future for today's standard, which is indispensable for pension and long-term planning. The Fisher formula links inflation to the other calculators, showing the true (real) return on deposits and investments.