Text Case Converter
Turn any short text into upper and lower case with length.
What it does
Case changes normalize headings, codes, and slugs. Upper shouts in banners, lower suits URLs and file names. Both derive from the same letters with numbers and marks untouched.
The tool above reads up to 200 characters and prints upper, lower, and length. The default Hello World matches the worked example, so the page opens showing HELLO WORLD. Type new text to update all three results.
Mapping follows Unicode defaults for basic Latin: a to z shift by 32 code points to A to Z. Digits, spaces, and punctuation have no case and copy through. Length counts code units you typed, spaces included.
Use upper for labels and lower for identifiers. For title case, convert then capitalize words in your editor. For ASCII codes instead of case, use an ASCII table tool.
This page shows the rules, one full hand checked example for Hello World, a short table, and practice checks that run through the tool.
How to use
- Type 1 to 200 characters.
- Read UPPERCASE as the loud form.
- Read lowercase as the quiet form.
- Read Length to size fields and limits.
- Copy the form your style guide wants.
- Split longer passages into 200 char chunks.
Formula
- upper
- Capitals for basic Latin letters.
- lower
- Small letters for basic Latin.
- count
- Characters including spaces.
Digits and marks have no case and pass through. Locale edge cases like Turkish dotted I are outside this basic form.
Worked example
Example: Hello World
Convert Hello World to cases.
- Input length: 11 chars with the space.
- Upper each letter: HELLO WORLD.
- Lower each letter: hello world.
- Digits would copy, none here.
- Space copies at position 6.
- Counts match at 11 chars.
Reference table
| Input | Upper | Lower |
|---|---|---|
| a | A | a |
| Z | Z | z |
| Hi! | HI! | hi! |
| Test 123 | TEST 123 | test 123 |
Limits
- Basic Latin focus. Some scripts have no case.
- 200 characters per run.
- Locale blind. Turkish I and German sharp s need locale tools.
- No title case output here.
Common mistakes
- Pasting over 200 chars and hitting the limit.
- Expecting title case from this upper/lower tool.
- Counting words instead of characters for length.
- Assuming numbers change with case.
- Using upper for passwords that need exact case.
Try it yourself
Quick checks. Answers sit tucked under each question.
Case for abc?
Upper ABC, lower abc, 3 chars.
Case for Test 123?
Upper TEST 123, lower test 123, 8 chars.
Questions
Upper of Hello World?
HELLO WORLD.
Lower?
hello world.
Length?
11 chars with the space.
Numbers?
They copy unchanged.
Limit?
200 characters per run.
Title case?
Not here. Upper then capitalize words in your editor.