Binary editor
Inspect a file's bytes in hexadecimal and replace values at selected offsets. Undo edits, then obtain the edited content as a separate file or hexadecimal text.
What you can do
Inspect byte offsets and values
View byte offsets, hexadecimal values and ASCII together. Enter an offset to move to a specific byte.
Replace individual bytes and save
Replace an existing byte with a value from 00 to FF, undo recent edits and download the edited content as a separate file.
How to use it
Load a file or hexadecimal bytes
Choose one file or enter a sequence such as 41 42 0A and load it. The limit is 1 MiB.
Select a byte to edit
Select a value in the table or enter its offset in decimal or hexadecimal with a 0x prefix.
Apply the new value
Enter a two-digit value from 00 to FF and press Replace byte. You can undo edits one at a time.
Save the edited content
Download a separate binary file. You can also copy the hexadecimal bytes or save them as text.
When it helps
Inspect a file header
Read the first bytes of a file to gather information about its format.
Change a value at a known offset
Check the offset and original value, replace the required byte and save a separate file.
Reading byte offsets and hexadecimal values
Offsets begin at zero
An offset is a position counted from the start of the file. Hexadecimal 0x1A and decimal 26 identify the same byte.
One byte uses two hexadecimal digits
Values from 00 to FF represent decimal values from 0 to 255. For example, 41 corresponds to the ASCII character A.
The ASCII display has a limited range
The display shows ASCII characters from 0x20 to 0x7E. Other values appear as dots. It does not detect or reconstruct text encodings such as Japanese.
Byte replacement and file structure
Replacing an existing byte keeps the file length unchanged. Changed values can make a file unreadable, so keep the original and check the edited result.
Ways to undo changes
Undo byte edit reverses the most recent byte change. Restore the loaded bytes returns to the last successfully loaded file or hexadecimal input and clears the undo history.
Frequently asked questions
Can I add or delete bytes?
This page replaces existing bytes. It does not change the file length by inserting or deleting bytes.
Will it overwrite my original file?
No. The edited content is downloaded with edited_ added to the file name.
How many edits can I undo?
You can undo the latest 1,000 byte edits. Reloading a file establishes a new starting point.
What hexadecimal input is accepted?
Use two-digit values from 00 to FF with optional spaces or line breaks. Do not include 0x prefixes or an offset column. Loading an empty field creates a zero-byte file.
How large can the file be?
One file can be up to 1 MiB (1,048,576 bytes). The table displays 256 bytes per page.
Inputs and results
- Input
- One file or hexadecimal byte sequence, up to 1 MiB.
- Editing
- Replace a byte at a selected offset, undo recent edits or restore the loaded bytes.
- Result
- An edited binary file, copied hexadecimal bytes or a hexadecimal text file. The original file is not overwritten.