📈 Percentage change calculators

Written by Rohan Mehta Updated
Editorial details Reviewed by Vikram Sen Verified · Methodology · Accuracy policy

Quick answer

Compare two values with increase, decrease, signed change, difference, or error against a reference—each tool states the denominator.

Increase %: ((new − original) / original) × 100 · Decrease %: ((original − new) / original) × 100 · Percent error: |measured − true| / |true| × 100

Best for: KPI deltas, price moves, lab error, A/B metric shifts.

Also see: Basic math · Statistics hub · Percentage guide

When comparing two measurements, choose increase or decrease if direction is fixed, or signed change when the outcome can go either way.

Key facts

Percent increase ((new − original) ÷ original) × 100 when original is the baseline.
Category Analytics / measurement
Related concepts Percentage points, successive change, reverse percentage.

Definitions

Percent increase

New minus original, divided by original, times 100—original must be nonzero.

Percent difference

Symmetric comparison of two values without forcing a single baseline.

Comparison table

Topic Guidance
Increase vs signed change Increase assumes growth framing; signed change allows negative outcomes.
Difference vs change Difference is often symmetric; change picks a baseline denominator.

❓ Frequently Asked Questions

Which baseline should I use?

Use the original or reference value as the denominator unless your policy specifies otherwise.

Where is year-over-year change?

Use percentage change or increase with prior-period and current values as original and new.

Glossary references

Pair percent language with conversion pages when you mix fractions, decimals, and ratios.