Maths Calculators
Everyday operations solved step by step: percentages, rule of three and discounts.
Percentage Calculator
Work out percentages, discounts and increases in one place: what a percentage of a value is, what percentage one figure is of another, and what happens to a price when it rises or falls by a given percentage.
Open calculator →Rule of Three Calculator
Solve any rule of three, direct or inverse: enter the three known values and get the fourth, with the proportion and the formula used explained step by step.
Open calculator →Discount Calculator
Work out the final price of a reduced item and how much you save: enter the original price and the discount percentage. It also works in reverse, to check what discount you are actually being given.
Open calculator →Spanish working days
Counts the working days between two dates and works out when a deadline falls. It does it under the three regimes that coexist in Spanish law, because the same two dates give three different answers depending on which kind of deadline you are counting.
Open calculator →Spanish statutory and late-payment interest calculator
An unpaid Spanish debt earns interest, and not every debt at the same rate. Enter the amount and the two dates and see what yours adds up to.
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About the maths calculators
These are the operations that come up constantly and that almost nobody remembers: what a percentage of an amount is, what percentage one figure is of another, what is left after a discount. Each calculator shows the full working, so you can repeat it without the tool.
Learn
- How to calculate a percentage →
- How to do a rule of three →
- Spanish working days explained →
- The Spanish statutory interest rate →
The calculators provide educational estimates and do not constitute financial advice.