How to use it
- Choose the question you want to answer.
- Enter the base and the required comparison or percentage value.
- Calculate to see the substituted formula and result.
Everyday Utilities · Local-first · Beta
Percentage Calculator
Work out a percentage of a number, what percentage one value is of another, or percentage change.
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Trust record
Check the method before you rely on the result
- Method
- Decimal-safe percentage arithmetic with three explicit modes and formula substitution.
- Percentage of = base × percentage ÷ 100; change = (new − base) ÷ base × 100
- Effective period
- Formula-based; no statutory effective period
- Last verified
- 10 August 2026
- Review every 365 days
- Reviewer status
- Product and domain review: specialist approval not required
- Privacy
- Inputs and results stay in this browser. Values are not sent to analytics, a backend, a URL or a log, and are not saved by default.
Important limitations
- The tool does not interpret the business meaning, tax treatment or unit behind a number.
- Percentage change uses the base value as its denominator.
Browse Everyday Utilities · Methodology · Sources
A quick guide
Use the number with context
The answer is only useful when you know what it includes and what it leaves out.
Formula
Percentage of = base × percentage ÷ 100; change = (new − base) ÷ base × 100
A percentage is meaningful only when the base and units are clear.
Make it concrete
Worked example
20% of ₹1,000 is ₹200. A move from ₹1,000 to ₹1,200 is a 20% increase.
Boundaries
What this tool does not assume
Limitations
- The tool does not interpret the business meaning, tax treatment or unit behind a number.
- Percentage change uses the base value as its denominator.
Edge cases
- A zero base is not accepted for percentage-of-change modes.
- Negative values are retained as entered so the direction is visible.
Last reviewed 10 August 2026 · Formula version 1.0
Method & sources
How this result is grounded
The formula is deterministic and runs in your browser. Read the reference below for the method used by this tool.
- Everyday Utilities methodology v1
KarobarKit controlled methodology · authoritative reference · Checked 10 August 2026
Supports: everyday utility formulas · rounding and scope limitations · privacy boundary
Questions
Frequently asked
Does percentage change use the old value as the base?
Yes. The original or base value is the denominator for percentage change.
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Source register checked 10 August 2026.