Limits

Feature	Limit
Data storage per bucket	Unlimited
Maximum number of buckets per account	1,000,000
Maximum rate of bucket management operations per bucket 1	50 per second
Number of custom domains per bucket	50
Object key length	1,024 bytes
Object metadata size	8,192 bytes
Object size	5 TiB per object 2
Maximum upload size 3	5 GiB (single-part) / 4.995 TiB (multi-part) 4
Maximum upload parts	10,000
Maximum concurrent writes to the same object name (key)	1 per second 5

Limits specified in MiB (mebibyte), GiB (gibibyte), or TiB (tebibyte) are storage units of measurement based on base-2. 1 GiB (gibibyte) is equivalent to 2³⁰ bytes (or 1024³ bytes). This is distinct from 1 GB (gigabyte), which is 10⁹ bytes (or 1000³ bytes).

Need a higher limit?

To request an adjustment to a limit, complete the Limit Increase Request Form ↗. If the limit can be increased, Cloudflare will contact you with next steps.

Rate limiting on managed public buckets through r2.dev

Managed public bucket access through an r2.dev subdomain is not intended for production usage and has a variable rate limit applied to it. The r2.dev endpoint for your bucket is designed to enable testing.

• If you exceed the rate limit (hundreds of requests/second), requests to your r2.dev endpoint will be temporarily throttled and you will receive a 429 Too Many Requests response.
• Bandwidth (throughput) may also be throttled when using the r2.dev endpoint.

For production use cases, connect a custom domain to your bucket. Custom domains allow you to serve content from a domain you control (for example, assets.example.com), configure fine-grained caching, set up redirect and rewrite rules, mutate content via Cloudflare Workers, and get detailed URL-level analytics for content served from your R2 bucket.

Footnotes

1. Bucket management operations include creating, deleting, listing, and configuring buckets. This limit does not apply to reading or writing objects to a bucket. ↩

2. The object size limit is 5 GiB less than 5 TiB, so 4.995 TiB. ↩

3. Max upload size applies to uploading a file via one request, uploading a part of a multipart upload, or copying into a part of a multipart upload. If you have a Worker, its inbound request size is constrained by Workers request limits. The max upload size limit does not apply to subrequests. ↩

4. The max upload size is 5 MiB less than 5 GiB, so 4.995 GiB. ↩

5. Concurrent writes to the same object name (key) at a higher rate return HTTP 429 (rate limited) responses. ↩