Generate an exact-size binary test file
Create raw bytes for transfer, storage and size-limit tests. Choose an exact count; this file is not a substitute for an image or document fixture.
1 MB = 1,000,000 B · 1 MiB = 1,048,576 B
Advanced: test an upload limit
Enter the byte limit above, then choose one byte below, the exact limit or one byte above. Each choice uses the same base: 10,485,760 B. Generate and download each file to test your endpoint.
BIN, built to spec.
Each file is raw bytes with no container at all. The size you ask for is reached with the entire file is pseudo-random printable bytes, so the result opens in hex editors like HxD or xxd, and Python's open() in binary mode. Most people generate these for measuring throughput and testing hard byte limits.
Choose a size here
These options set the generator above. Separate size guides explain how to test a particular upload boundary.
Guides for specific upload limits
File structure and testing limits
Raw generated bytes without a format header. Suitable for transfer and size checks; unsuitable when an endpoint requires a real image or document.
Format reference: RFC 2046 octet-stream.
This generator assembles the file in your browser; file content is not sent to a server. Site analytics may make network requests. Office ↔ PDF conversion uses a separate server workflow. Data processing and privacy.
Technical notes for every format · Guide to testing file upload limits
Questions
How small can a BIN file be?
About 1 byte. Below that the format cannot carry its mandatory structure, let alone padding.
Will the file open normally?
Validate the generated fixture in your target application. Parts added for exact size may change or disappear when the file is re-saved; compatibility depends on the reader.
Can I ask for an unusual size?
Any byte count above the minimum works — for example 3,145,728 bytes (exactly 3 MB) or 27.5 MB. Drag the caliper or type the number.
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