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HTTP Status Codes

Look up what any HTTP status code means, in plain English.

Use it as often as you like — it's free, with no sign-up and no limits.

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1xx Informational

100
Continue
The server got the request headers and the client can send the body.
101
Switching Protocols
The server is switching protocols as requested, for example to WebSocket.
103
Early Hints
Preliminary headers so the browser can start preloading resources before the final response.

2xx Success

200
OK
The request worked and the response contains the result.
201
Created
The request worked and a new resource was created.Tip: APIs usually return the new resource's URL in a Location header.
202
Accepted
The request was accepted for processing, but the work isn't finished yet.
204
No Content
The request worked and there's nothing to send back.
206
Partial Content
Only part of the file was sent, because the client asked for a range (used for video streaming and resumable downloads).

3xx Redirection

301
Moved Permanently
The page has a new permanent address. Browsers and search engines should use the new URL.Tip: Use 301 (or 308) when moving pages so search rankings carry over.
302
Found
The page is temporarily at a different address. Keep using the original URL.
303
See Other
Go to another URL with a GET request — common after submitting a form.
304
Not Modified
The cached copy is still up to date, so nothing new was sent.
307
Temporary Redirect
Temporarily moved; repeat the same request (same method and body) at the new URL.
308
Permanent Redirect
Permanently moved; repeat the same request (same method and body) at the new URL.

4xx Client error

400
Bad Request
The server couldn't understand the request — often malformed JSON or missing fields.
401
Unauthorized
You need to log in or send valid credentials.Tip: Despite the name, this means “unauthenticated”.
402
Payment Required
Reserved for payment flows; some APIs use it when a subscription or credit is needed.
403
Forbidden
The server knows who you are but you're not allowed to access this.
404
Not Found
Nothing exists at this address.Tip: Make sure removed pages return 404 (or 410), not a 200 page that says “not found”.
405
Method Not Allowed
The URL exists but doesn't accept this method (for example POST instead of GET).
406
Not Acceptable
The server can't produce a response in any format the client accepts.
408
Request Timeout
The client took too long to send the request.
409
Conflict
The request conflicts with the current state, such as editing an outdated version.
410
Gone
The resource was deliberately removed and won't come back.
411
Length Required
The server needs a Content-Length header.
412
Precondition Failed
A condition in the request headers (like If-Match) wasn't met.
413
Content Too Large
The request body (often an upload) is bigger than the server allows.
414
URI Too Long
The URL is longer than the server will process.
415
Unsupported Media Type
The server doesn't accept the body's format — check the Content-Type header.
416
Range Not Satisfiable
The requested byte range is outside the file.
418
I'm a teapot
An April Fools' joke from 1998 (RFC 2324). Some services use it playfully.
422
Unprocessable Content
The request is well-formed but the data fails validation.
425
Too Early
The server won't risk processing a request that might be replayed.
426
Upgrade Required
The client must switch to a different protocol, such as a newer TLS version.
428
Precondition Required
The server requires conditional requests to prevent lost updates.
429
Too Many Requests
You've hit a rate limit. Slow down and retry later.Tip: Look for a Retry-After header telling you how long to wait.
431
Request Header Fields Too Large
The headers (often cookies) are too big.
451
Unavailable For Legal Reasons
Access is blocked for legal reasons, such as a court order.

5xx Server error

500
Internal Server Error
Something went wrong on the server. It's not your fault.Tip: Check the server logs for the underlying error.
501
Not Implemented
The server doesn't support the functionality needed.
502
Bad Gateway
A proxy or load balancer got an invalid response from the server behind it.
503
Service Unavailable
The server is overloaded or down for maintenance. Try again later.Tip: Use 503 with Retry-After during planned maintenance so search engines don't drop pages.
504
Gateway Timeout
A proxy didn't get a response from the upstream server in time.
505
HTTP Version Not Supported
The server doesn't support the HTTP version used.
507
Insufficient Storage
The server can't store what's needed to complete the request.
508
Loop Detected
The server found an infinite loop while processing.
511
Network Authentication Required
You need to log in to the network, like a hotel or airport Wi-Fi portal.

The calculation happens instantly in your browser. The numbers you enter are not sent to our servers or saved.

How to use the HTTP Status Codes

  1. Search by number (404) or by word (redirect).
  2. Read the explanation and practical tip.

What does this tool do?

Every web response starts with a three-digit status code. The first digit tells you the class: 1xx information, 2xx success, 3xx redirection, 4xx a problem with the request, and 5xx a problem on the server.

Why use it?

  • Understand errors from websites and APIs.
  • Choose the right code when building an API.
  • Avoid SEO mistakes with redirects and 404s.

SEO tip

Use 301 or 308 for permanent moves, so search engines transfer signals to the new URL, and make sure missing pages return a real 404 — not a “soft 404” page with a 200 status.

Privacy

The calculation happens instantly in your browser. The numbers you enter are not sent to our servers or saved. There's no account to create and nothing to install.

Frequently asked questions

What's the difference between a 301 and a 302 redirect?

A 301 is permanent: search engines move ranking signals to the new URL. A 302 is temporary: the original URL stays indexed. Use 301 when a page has moved for good.

What's the difference between 401 and 403?

401 Unauthorized means you're not logged in or your credentials weren't accepted. 403 Forbidden means the server knows who you are but you don't have permission.

Last reviewed by the M2Toolkit team.

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