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ISO 8601 date converter (RFC 2822, HTTP)

Turn any date, time and UTC offset into ISO 8601, RFC 3339, week/ordinal date, RFC 2822, HTTP date and Unix timestamps.

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Open ISO 8601 date converter (RFC 2822, HTTP) and you get an answer straight away, with no account to create. Its place is under JSON, XML & formats; HTTP Status Code Reference and Paper Size Reference (A4, Letter, ISO 216) answer the questions closest to this one.

How to use it

  1. Open the tool — no signup or install needed.
  2. Enter your input or adjust the available options.
  3. Get your result instantly, then copy or download it.

Frequently asked questions

What does ISO 8601 date converter (RFC 2822, HTTP) do?

Turn any date, time and UTC offset into ISO 8601, RFC 3339, week/ordinal date, RFC 2822, HTTP date and Unix timestamps.

When would I actually use this?

Making a machine-generated blob readable, finding the character where a parse fails, and shrinking a file before it ships.

What is the most common mistake?

Assuming valid means correct. A document can parse cleanly and still have the wrong shape for whatever will read it — validation checks the syntax, not the schema.

How is ISO 8601 date converter (RFC 2822, HTTP) different from HTTP Status Code Reference?

They sit next to each other but answer different questions. HTTP Status Code Reference: search and browse every standard HTTP status code by class, with its name and a one-line description. Pick whichever matches what you're starting from — both are free.

Is there a tool for the next step?

Paper Size Reference (A4, Letter, ISO 216) is the closest one after this: Every A, B, C and US paper size in mm, cm and inches, pixel dimensions at 72 to 600 dpi, a scale drawing against A4 and Letter, and the √2 rule explained.

What else is worth having open alongside it?

CSS Beautifier and HTML Beautifier — they come up in the same task often enough to be worth a second tab.

Where do the figures come from?

Parsing and serialisation follow each format's specification. Key order and whitespace are not semantically meaningful in JSON or YAML, so a reformatted document is equivalent even when the bytes differ.

Further reading

All guides →
ExplainerWriting a Date as ISO 8601, and Why It Is the Only Unambiguous Format01/02/2026 is 1 February in most of Europe and 2 January in the United States, and nothing in the string says which. ISO 8601 fixes that, sorts as text, and stops being ISO 8601 in four specific places that RFC 3339 rejects.ExplainerReading and Writing Military Time0800 is not “eight o'clock” and not “08:00” — it is “zero eight hundred”, with a zone letter on the end. The four digits, the spoken form, midnight at 0000, the argument about 2400, and the reason 12-hour notation cannot settle noon.GuideWhat a Minifier Can Remove, and What It Must NotMinification has to preserve meaning, and the interesting part is the whitespace that carries meaning: the descendant combinator, the spaces inside calc(), the gap between two inline elements. Measured here on real files, including how much brotli was going to save you anyway.GuideBeautify or Minify: What Each Is For, and What It Does to the WeightFour real stylesheets run through the minifier, measured raw and after gzip. Stripping every space saved 48, 103, 104 and 147 compressed bytes; stripping comments saved 57, 1 358, 2 420 and 1 042. Plus the five inputs this minifier breaks.How-toBuilding a Markdown Table From Scratch, Without Counting Dashes by HandThe smallest thing that is still a table is two lines: a header row and a delimiter row. Here is why the second one is mandatory in GitHub Flavored Markdown, where pipe tables do not exist at all, and what a generator does that hand-typing cannot.GuidePasting a Table Into a Pull Request: What Breaks, and the Two Characters That Break ItA Markdown table has exactly two forbidden characters in a cell: the pipe and the line break. Here is what each one does, how a converter handles them, why the escape has to be applied in the right order, and why padding never matters.