# Regex Tester

> Test JavaScript regular expressions and capture groups.

Page: https://freecalculator.tech/tools/regex-tester

## Formula

Uses the browser's JavaScript RegExp engine and reports match ranges and capture groups.

- Uses the browser's JavaScript RegExp engine and reports match ranges and capture groups.
- Inputs used: Regular expression, Test text.

## Worked example: Find capitalized words

Match capitalized words and inspect their positions.
1. Start with Regular expression: \b[A-Z][a-z]+\b, Test text: Hello from Free Calculator.
2. Apply the method: Uses the browser's JavaScript RegExp engine and reports match ranges and capture groups.
3. Match capitalized words and inspect their positions.

## Common questions

### Is my input uploaded?

No. Your input is processed locally in your browser and is not sent to the server or included in analytics.

### Can I use the regex tester output elsewhere?

Yes. Use Copy, or Download when available, after reviewing the output.

### How do I use the Regex Tester?

Enter the required values for Regular expression, Test text. The calculator applies the formula on this page and shows the main result with any supporting breakdown so you can check the arithmetic.

### What formula does the Regex Tester use?

Uses the browser's JavaScript RegExp engine and reports match ranges and capture groups. The visible formula section above lists the calculation path and the edge cases the page handles, so the result can be checked without relying on the form alone.

### Can the Regex Tester be used for exact decisions?

Use it as a calculation aid, not as a substitute for checking the underlying rule, contract, policy, or professional advice that applies to your situation. When a result depends on local rules, personal details, prices, or dates, enter those values yourself and confirm them before acting.

## Limitations and assumptions

- The result depends on the values you enter for this regex tester; it does not supply missing rates, rules, prices, dates, or assumptions for you.

## Cite this page

- APA: Free Calculator. (n.d.). Regex Tester. https://freecalculator.tech/tools/regex-tester
- MLA: "Regex Tester." Free Calculator, https://freecalculator.tech/tools/regex-tester.
- Link: Regex Tester — Free Calculator, https://freecalculator.tech/tools/regex-tester