20 MB ICS sample
An ICS file of exactly 20,971,520 bytes. It is a valid iCalendar file file, generated by this site. Compare its checksum and test it with the parser used by your application. Use it wherever you need a 20 MB sample, test or dummy ICS file.
Download
sample-ics-20mb.ics
20 MB20,971,520 bytes
Download 20 MB ICSCreated in your browser in a few seconds, then checked against the SHA-256 checksum. The file is not uploaded anywhere. No sign-up.
- Type
- text/calendar
- SHA-256
8ce5efb9cd93e0fccf1d0d77d86aa91eb623981e69050aaedcb1b4cae66cfef6- Delivery
- Created in your browser from static generator assets (how it works).
What is in this file
A VCALENDAR with 61,304 one-hour events, each with a UID, start and end in UTC, a summary, a folded description and an escaped location. Extension properties (X-FIXTURE-PAD), which calendar programs ignore, bring the file to the exact size.
| Events | 61,304 |
|---|---|
| Version | iCalendar 2.0 (RFC 5545) |
| Time zone | UTC |
| Line endings | CRLF, folded at 75 octets |
| Encoding | UTF-8 (ASCII characters only) |
How the file begins
The opening lines of sample-ics-20mb.ics, exactly as they appear in the file.
00000000 42 45 47 49 4e 3a 56 43 41 4c 45 4e 44 41 52 0d |BEGIN:VCALENDAR.|
00000010 0a 56 45 52 53 49 4f 4e 3a 32 2e 30 0d 0a 50 52 |.VERSION:2.0..PR|
00000020 4f 44 49 44 3a 2d 2f 2f 53 61 6d 70 6c 65 54 65 |ODID:-//SampleTe|
00000030 73 74 46 69 6c 65 73 2f 2f 53 61 6d 70 6c 65 20 |stFiles//Sample |Preview
Creates the file in your browser and shows the first 64 KB of it.
Where 20 MB matters
A 20,971,520-byte file: right at the default attachment limit of Outlook, and just under the 25 MB ceilings of Gmail and GitHub web uploads. These are the default limits a file of this size is useful for testing:
| System | Limit | Note |
|---|---|---|
| Microsoft Outlook | 20 MB of attachments by default for internet mail accounts | This file is right at the limit; add a second attachment and it is exceeded. |
| Gmail | 25 MB per message | Under the limit, although email encoding adds about a third in transit. |
| GitHub web uploads | 25 MiB per file added through the browser | Accepted. Pushing with Git allows larger files. |
| Cloudflare Pages assets | 25 MiB per file | The largest round size that can be served as a static asset. |
| Amazon API Gateway | 10 MB payload | Rejected; the upload has to go directly to object storage. |
| ASP.NET Core (Kestrel) | About 28.6 MB request body by default | Accepted with room for the multipart overhead. |
Use this file for
- Finding the first upload limit in a new stack
- Testing invitation processing
- Testing calendar import and subscription
Testing notes for ICS
- Time zones and recurrence rules are where calendar software fails. The samples use UTC and non-recurring events, so they work as a known-good baseline.
- Importing the same UID twice should update an event, not duplicate it.
Technical details
| File name | sample-ics-20mb.ics |
|---|---|
| Format | ICS (iCalendar file) |
| Extension | .ics |
| MIME type | text/calendar |
| Size | 20,971,520 bytes (20 MB) |
| Kind | Text |
| SHA-256 | 8ce5efb9cd93e0fccf1d0d77d86aa91eb623981e69050aaedcb1b4cae66cfef6 |
| Created | 2026-10-23 |
| Validation | See the listed size and SHA-256. Small downloads are checked in the browser; verify streamed downloads manually. A hash match does not prove parser compatibility. |
| Preview | Available on this page |
| Source | Generated in your browser by this site's generator; not copied from elsewhere |
| Licence | Free to use, modify and redistribute (terms) |
| Category | Email & Calendar |
Check the stated structure and checksum against your application requirements. As with any download, scan the file with your own security tools before opening it. How files are made and checked
Verify your copy
This file is created in your browser, so it has no direct URL for curl or wget. The generator is designed to produce reproducible bytes. After saving, compare the checksum with the SHA-256 value above.
sha256sum sample-ics-20mb.ics # Linux
shasum -a 256 sample-ics-20mb.ics # macOSOn Windows, run Get-FileHash sample-ics-20mb.ics -Algorithm SHA256 in PowerShell. For scripts and pipelines, save the file once and keep your own copy.
Related files
Questions about this file
- Is this file exactly 20 MB?
- Yes. It is 20,971,520 bytes, which is 20 MB in the binary units that operating systems and server limits use (1 KB = 1,024 bytes).
- What is inside the 20 MB ICS file?
- A VCALENDAR with 61,304 one-hour events, each with a UID, start and end in UTC, a summary, a folded description and an escaped location. Extension properties (X-FIXTURE-PAD), which calendar programs ignore, bring the file to the exact size.
- Do the events repeat?
- No. Each event is a single one-hour meeting in UTC with its own UID.