THE WHOLE TOOLKIT / 36 TOOLS
A good place to find
your answer.
A quick calculation. A tricky equation. A plan taking shape.
Pick your starting point and make the numbers make sense.
Percent of a number
Find the amount represented by a percentage of any base value.
Percentage increase
Compare an original value with a new one to measure relative growth.
Percentage decrease
Measure how much a value has fallen relative to where it started.
Percent change
Keep the sign of a change so growth and decline are easy to distinguish.
Percentage difference
Compare two numbers equally, without choosing a starting value.
Compound interest
See how a starting amount grows when interest also earns interest.
Simple interest
Calculate interest on the starting principal without compounding.
Loan repayment
Estimate the fixed monthly payment and total interest on a loan.
Mortgage payment
Put principal, interest, property tax and insurance into one monthly estimate.
Profit margin
Separate revenue, direct costs and operating expenses to understand profitability.
Return on investment
Compare an investment’s final value with its initial cost.
Basic calculator
Keep arithmetic simple with a clear expression and standard operation order.
Fraction calculator
Add, subtract, multiply or divide two fractions and simplify the result.
Simplify a fraction
Cancel common factors to express a fraction in its simplest form.
Equivalent fractions
See different-looking fractions that represent the same amount.
Decimal to fraction
Turn a finite decimal into an exact fraction, then reduce it.
Simplify a ratio
Compare two positive quantities with a smaller equivalent pair.
Area calculator
Choose a shape and find how much flat space it covers.
Rectangle area
Find the area and perimeter from two perpendicular sides.
Circle area
Start with a radius or diameter to find area and circumference.
Triangle area
Use a base and its perpendicular height to measure a triangle.
Volume calculator
Find the space inside a cube, cylinder or sphere.
Everyday percentage calculator
Switch between finding an amount, a percentage share or a change.
Solve for x
Collect variable terms on either side and uncover a linear equation’s solution.
Quadratic equation solver
Find two real roots, a repeated root or a complex pair.
Polynomial calculator
Add, subtract or multiply expanded single-variable polynomials.
Factor a polynomial
Look for common factors and rational linear factors in a quadratic.
From x + 2 = 5 to x = 3
Practice undoing addition and multiplication with an editable example.
Trigonometry calculator
Explore trigonometric functions and the angle units behind the answer.
Inverse trigonometry
Find the principal angle for a sine, cosine or tangent ratio.
Logarithm calculator
Ask what exponent turns a chosen base into your number.
Root calculator
Find the real square, cube or nth root of a number.
Exponent calculator
Raise a base to a positive, negative or fractional power.
Factorial calculator
Count ordered arrangements by multiplying consecutive whole numbers.
Fraction to percent
Express a numerator and denominator as a percentage and a decimal.
Math constants
A small reference shelf for numbers that show up everywhere.
No tools found
Try a shorter term, such as “loan”, “area” or “fraction”.
A result is only the beginning.
Every calculator includes its formula, assumptions and worked steps. Start with the example, then try your own numbers.