---
title: Limits
description: Account, bucket, and object limits for Cloudflare R2 storage.
pcx_content_type: concept
products:
  - r2
---

import { Render } from "~/components";

| Feature                                                      | Limit                                             |
| ------------------------------------------------------------ | ------------------------------------------------- |
| Data storage per bucket                                      | Unlimited                                         |
| Number of objects per bucket                                 | Unlimited                                         |
| Maximum number of buckets per account | Unlimited, with a default limit of 100,000. Each bucket above 100,000 costs [$0.10 per month](/r2/pricing/#r2-pricing). |
| Maximum rate of bucket management operations per bucket [^1] | 50 per second                                     |
| Number of custom domains per bucket                          | 100                                               |
| 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]                                 |

[^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](/workers/platform/limits#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.

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 2<sup>30</sup> bytes (or 1024<sup>3</sup> bytes). This is distinct from 1 GB (gigabyte), which is 10<sup>9</sup> bytes (or 1000<sup>3</sup> bytes).

<Render file="limits_increase" product="workers" />

## 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](/r2/buckets/public-buckets/#custom-domains) 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](/workers/), and get detailed URL-level analytics for content served from your R2 bucket.

## Cloudflare REST API

The [Cloudflare REST API](/api/resources/r2/) is rate limited to 1,200 requests per five minutes across all R2 REST API operations on your account.

For high-throughput object operations, use the [S3-compatible API](/r2/api/s3/api/) or [Workers API](/r2/api/workers/workers-api-reference/) instead. The Cloudflare REST API is best suited for lower-volume management and configuration operations.