AnyCalc

Developer Tools

HTTP Status Code Reference

Look up HTTP status codes and their meanings

Reviewed: AnyCalc Editorial|2026-07-19|Editorial policy|About

What this calculator does

HTTP status codes are three-digit numbers returned by servers to indicate the result of a client request. This reference tool provides a complete, searchable catalog of all standard HTTP status codes organized by class: 1xx informational, 2xx success, 3xx redirection, 4xx client error, and 5xx server error. Each code includes its official name, a plain-English explanation of when it is returned, common causes, and developer troubleshooting tips. Understanding status codes is fundamental for debugging API integrations, configuring web servers, handling errors gracefully in applications, and diagnosing SEO crawl issues. Bookmark this as a quick reference for the codes you encounter daily.

1xx Informational

2xx Success

3xx Redirection

4xx Client Error

5xx Server Error

How to use

  1. 01
    Search or browse
    Enter a status code number or browse by category (1xx-5xx).
  2. 02
    Read the details
    View the status name, description, and common use cases.
  3. 03
    Use in your project
    Apply the correct status code in your API or server response.

HTTP Status Code Reference FAQ

What is the difference between 301 and 302 redirects?▾
A 301 is a permanent redirect — search engines transfer ranking authority to the new URL. A 302 is a temporary redirect — search engines keep the original URL indexed. Use 301 when a page has permanently moved; use 302 for temporary situations like maintenance or A/B testing.
What does a 403 Forbidden status code mean?▾
A 403 means the server understood the request but refuses to authorize it. Unlike 401 (Unauthorized), authentication will not help. Common causes include insufficient file permissions, IP restrictions, directory listing being disabled, or WAF rules blocking the request.
When should an API return 404 vs 410?▾
Return 404 when a resource is not found and may or may not have existed. Return 410 when you know the resource previously existed but has been permanently deleted. 410 signals to search engines to remove the page from their index faster than a 404.

Interpret carefully

Outputs are decision-support estimates, not a substitute for professional judgment.

  • Treating HTTP Status Code Reference output as a final professional diagnosis, quote, or legal determination
  • Entering approximate values when the result is sensitive to units or precision
  • Applying the FAQ answer (“What is the difference between 301 and 302 redirects?”) to a special case without checking assumptions

Next steps

  1. Double-check inputs against your source documents (labs, statements, specs, or notes).
  2. Confirm the method below matches your use case before you act on the number.
  3. For medical, financial, or production decisions, verify with a qualified professional.

Disclaimer: Results are informational only and do not constitute medical, financial, legal, or professional advice. Report issues: sublimernj@gmail.com

← Developer Tools