Savings and Investment Calculators
Free tools to see how your money grows. Start with compound interest.
Compound Interest Calculator
Work out how your money grows with compound interest: enter the starting amount, the monthly contribution, the annual interest rate and the term, and see the future value with a year-by-year breakdown.
Open calculator →Simple Interest Calculator
Work out simple interest on a capital sum: interest is always calculated on the starting amount and never reinvested. Enter the capital, the annual rate and the term to see the interest and the final value.
Open calculator →Inflation Calculator
See how much purchasing power your money loses to inflation: enter an amount, an average annual inflation rate and a term, and get the real value and the equivalent future cost.
Open calculator →Spanish Treasury Bill Calculator
Work out the real yield on a Spanish Letra del Tesoro from the price you paid, or the price implied by an auction yield, using the Tesoro’s own method, plus the gain after tax.
Open calculator →TAE – TIN Calculator (Spain)
Convert TIN to TAE and back: what rate you really pay or earn over a year when the nominal rate compounds monthly, quarterly or daily, with the Banco de España formula explained.
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About the savings and investment calculators
These calculators estimate how your money evolves over time: the interest it earns, the contributions you add and the effect of compounding. They are for understanding orders of magnitude, not for predicting returns. Each one explains the formula it uses and links to the article that develops the concept.
Learn
- What is compound interest? →
- Simple vs compound interest →
- What is inflation? →
- The return on Spanish Treasury bills →
- The difference between the TAE and the TIN →
The calculators provide educational estimates and do not constitute financial advice.