Compound interest calculator: estimate future value and total interest
Compound interest means interest is added to the balance and can then earn interest in later periods. Toolmera models that growth from your starting amount, annual interest rate, time horizon and selected compounding frequency.
The result separates the projected ending balance from the money you contributed, making it easier to see how much of the final value comes from contributions and how much comes from compound growth.
Starting balanceSet any principal amount
CompoundingAnnual, quarterly, monthly or daily
ContributionsOptional monthly amount
BreakdownYear-by-year growth
Compound interest for a fixed deposit
A fixed deposit or term-deposit calculation is a common compound-interest use case. If you are modelling a deposit with no additional monthly payments, set the monthly contribution to zero and enter the principal, annual rate, term and the compounding frequency used by the product.
The calculator estimates the mathematical growth from those inputs. It does not include product-specific taxes, penalties, early-withdrawal rules, fees or bank-specific calculation conventions, so compare the result with the terms published by the financial institution before making a financial decision.
How compounding frequency changes the result
With the same nominal annual rate, more frequent compounding can produce a different future value because interest is credited and begins participating in later growth more often. Toolmera lets you compare annual, quarterly, monthly and daily compounding without changing the other assumptions.
For a real savings account, investment or fixed deposit, use the compounding schedule stated in the product terms rather than choosing the frequency that produces the largest result.
Compound growth with monthly contributions
Regular contributions can materially change a long-term result because each added amount has its own remaining time to compound. Use the monthly contribution field for recurring savings or investment scenarios where you plan to add money throughout the term.
If you are modelling a single lump-sum deposit, leave monthly contributions at zero. This keeps the calculation focused on growth of the original principal.
Compound interest vs simple interest
Simple interest is calculated only on the original principal, while compound interest allows previously credited interest to participate in future growth. Over longer periods, that difference can become significant even when the stated annual rate is the same.
Use the Simple Interest Calculator when a product explicitly uses simple interest. For returns expressed as a percentage of profit or loss rather than an interest schedule, the ROI Calculator is usually a better fit.