Replace Letters in Text
Swap letters one-for-one, like a character substitution cipher. Runs entirely in your browser, so your data never leaves your device.
0 chars · 0 lines
Output
The result appears here as you type.
How to use Replace Letters in Text
- 1. Paste the text to substitute. Paste the passage you want transformed into the input pane, ready for a one-for-one character substitution across every matching letter.
- 2. Define the character mapping. Type the characters to replace into Replace these characters, and their matching replacements in the same order into With these characters, position by position.
- 3. Copy the substituted text. Copy the result from the output pane, where each listed character has been swapped for its mapped replacement, and paste it wherever needed.
When to use Replace Letters in Text
Replace Letters in Text swaps letters one-for-one according to a character mapping you define, like a simple substitution cipher. Reach for Replace Letters in Text when you need consistent character-level substitutions applied across a whole passage at once.
- Creating a custom substitution cipher message. A puzzle or game needs a message encoded with a custom letter mapping rather than a standard cipher, and defining your own character pairs here builds it directly.
- Simulating leetspeak-style character swaps. You want specific letters swapped for lookalike numbers or symbols, such as e for 3 and a for 4, and defining that exact mapping applies it consistently.
- Testing how text renders with alternate characters. Before finalizing a font or character substitution scheme, mapping specific letters to their replacements here previews how a passage would actually look.
Examples
Substitute letters
Input
hello
Output
he110
About the Replace Letters in Text tool
Replace Letters in Text does its work locally, right in the browser. Swap letters one-for-one, like a character substitution cipher. There is no upload step, no queue and no account, and your data never travels over the network.
It belongs to the Text Tools collection on EditSafely, a set of 211 small, focused Text utilities that share the same instant, private workspace.
You can shape the output with 2 settings, including Replace these characters and With these characters, and the result refreshes the moment you change one. A worked example further down the page shows exactly what the tool produces for a real input.
Running locally also makes the tool fast and dependable: results appear as you type or drop a file, there is no server outage that can take it down mid-task, and confidential data can be processed without a second thought.
Frequently asked questions
Is Replace Letters in Text free to use?
Yes, it is completely free. All 2,658 tools on EditSafely work without an account, a subscription or usage limits.
Is it safe to paste sensitive or confidential data?
Everything happens locally. Your browser downloads the tool's code once, then does all the processing itself; nothing you enter is transmitted, stored or logged. You can even go offline after the page loads and it will still work.
How much text can I process at once?
There is no fixed limit. Because the work happens on your own device rather than on a shared server, the practical ceiling is your machine's memory, which comfortably handles inputs far larger than typical online tools allow.
Do I need to sign up or install anything?
No. The tool works in any modern browser on desktop, tablet or phone. There is no account to create, no extension to add and no software to install.
How do I use the result?
The output panel has a one-click copy button, and you can keep refining the input while you work; the result updates in place as you type.