What this calculator does
Case sensitive means that a program treats uppercase and lowercase letters as different characters, so "Password" and "password" are not the same string even though a person reading them would consider them the same word. This tool compares two pieces of text and shows both results at once: whether they match exactly, letter case included, and whether they match once case is ignored.
The gap between those two results is what case sensitive actually means in practice. Usernames, passwords, file names and programming variable names are commonly case sensitive, so "Admin" and "admin" can be treated as two entirely different values. Search boxes, email addresses and most everyday text are usually case insensitive, so the same two strings are treated as identical.
The formula
The exact match compares the two strings character by character with no changes, so any difference in letter case, spacing or characters counts as a mismatch. The case-insensitive match converts both strings to lowercase first, then compares them, so only the letters and their order matter, not how they were capitalised.
| Term | Meaning |
|---|---|
| Case sensitive | Uppercase and lowercase letters are treated as different characters, so identical wording in different case does not match. |
| Case insensitive | Uppercase and lowercase letters are treated as the same, so identical wording matches regardless of capitalisation. |
| Exact match | The two strings are identical character for character, including case. |
The inputs explained
| Field | What to enter |
|---|---|
| First text | The first piece of text to compare. |
| Second text | The second piece of text to compare against the first. |
When to use it
Checking a password or username rule
Many login systems are case sensitive on the password but not the username. Typing the two versions in here shows exactly why "Summer2024" and "summer2024" can be rejected as different passwords while "User1" and "user1" log into the same account.
Comparing file names or code identifiers
File systems and programming languages vary in whether they are case sensitive. Two file names or variable names that look the same to the eye can be treated as different if the underlying system is case sensitive.
Understanding a failed text match
A spreadsheet lookup, form validation or search that unexpectedly fails to match two seemingly identical entries is often a hidden case mismatch. Pasting both values in shows whether case is the cause.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the same two words compare with different capitalisation
The same first text compared against several versions of the second text with different capitalisation.
| Second text | Result | Case-sensitive match (exact) | Case-insensitive match (ignoring case) |
|---|---|---|---|
| "Password123" | Identical, including letter case | Yes | Yes |
| "password123" | Same letters, different case | No | Yes |
| "PASSWORD123" | Same letters, different case | No | Yes |
| "Password124" | Different text | No | No |
Comparing a web address against different versions of itself
A domain-style example compared against a same-case copy, two differently-cased copies, and a genuinely different address.
| Second text | Result | Case-sensitive match (exact) | Case-insensitive match (ignoring case) |
|---|---|---|---|
| "Example.com" | Identical, including letter case | Yes | Yes |
| "example.com" | Same letters, different case | No | Yes |
| "EXAMPLE.COM" | Same letters, different case | No | Yes |
| "example.org" | Different text | No | No |
Questions
What is case sensitive meaning in simple terms?
It means uppercase and lowercase letters count as different characters. "Cat" and "cat" are the same word to a person, but a case-sensitive system treats them as two different pieces of text.
Is email case sensitive?
The domain part of an email address is not case sensitive, but technically the part before the @ symbol can be, depending on the mail server. In practice, almost every major email provider treats the whole address as case insensitive.
Are passwords always case sensitive?
Most modern systems make passwords case sensitive as a security measure, since it increases the number of possible combinations. It is worth checking the exact rules of a specific site rather than assuming.
Why does my search not find results with different capitalisation?
Most search tools are designed to be case insensitive by default, so this is unusual. If it happens, the tool in question may have a case-sensitive mode switched on, or the mismatch may involve something other than case, such as extra spaces or punctuation.
For rounding numbers rather than comparing text, see the rounding calculator.