Compare calculators

Both calculators run independently — change the inputs on either side to compare results.

Percentage Change Calculator

Calculate the percentage increase or decrease between an old value and a new value. The standard way to express growth, discounts, and rates of change.

Original Value

New Value

Math

Percent Error Calculator

Measure how far an estimated or measured value deviates from the true value as a percentage. Scientists, students, and engineers use it to assess the accuracy of experimental results.

Estimated Value

Exact (True) Value

Key differences

	Percentage Change Calculator	Percent Error Calculator
Category	Math	Math
Inputs required	2	2
Result	Percentage Change (%)	Percent Error (%)
What it does	Calculate the percentage increase or decrease between an old value and a new value. The standard way to express growth, discounts, and rates of change.	Measure how far an estimated or measured value deviates from the true value as a percentage. Scientists, students, and engineers use it to assess the accuracy of experimental results.