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Pad string / number

Pad each line to a fixed length with a chosen character, on the left or right.

Related tools

All Web & network tools →
Number base converterConvert numbers between all 35 bases, exactly, with two's complement.Number sequence generatorGenerate a list of numbers from a start, end and step.Ordinal number converterConvert numbers into English ordinals (1st, 2nd, 3rd…).JSON String Escape / UnescapeTurn raw text into a JSON-safe string and back, with control characters, \uXXXX, emoji surrogate pairs and lone surrogates handled exactly like JSON.stringify.JSON to query stringTurn a flat JSON object into a URL query string.Query String BuilderBuild a URL query string from key/value rows with correct percent-encoding, array syntax options and a UTM preset — or parse an existing URL back into rows.Query string to JSONParse a URL query string into JSON and build one back. Repeated keys become an array, tag[]= and filtre[prix]= expand into arrays and objects, + is a space and %C3%A9 is é.String escape / unescapeEscape a string for JSON/JavaScript or unescape it back to raw text.

Pad string / number works straight from this page — free, instant, nothing to install. It sits under Web & network in our catalogue, alongside Number base converter and Number sequence generator.

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 Pad string / number do?

Pad each line to a fixed length with a chosen character, on the left or right.

When would I actually use this?

Getting usable data out of something that was never meant to be parsed: pulling every address out of a pasted thread, turning a column of lines into a JSON array or an SQL IN clause, renaming a hundred identifiers from snake_case to camelCase in one pass.

What is the most common mistake?

Trusting an extraction to be exhaustive. A pattern that catches every address in the sample will still miss the one wrapped across a line break, the one written with a display name, and the one an email client turned into a link — count what came out against what you expected before you use the list.

How is Pad string / number different from Number base converter?

They sit next to each other but answer different questions: Number base converter is the one to open when you need it to convert numbers between all 35 bases, exactly, with two's complement. Pick whichever matches what you're starting from — both are free.

Is there a tool for the next step?

Number sequence generator is the closest one after this: Generate a list of numbers from a start, end and step.

Where do the figures come from?

Extraction runs on patterns, not on a parser: it recognises the common shapes of an address, a URL or an IP rather than validating them against their specification. That is the right trade for a paste, and the wrong one for input you are about to store.

Further reading

All guides →
ExplainerEscaping a String for JSON: Three Characters Are Mandatory, and One Is a TrapRFC 8259 requires exactly three things to be escaped inside a JSON string. Everything else is optional. The one that actually breaks pipelines is a lone surrogate — legal in JSON text, impossible in UTF-8, and silently replaced the moment your data is written out.ExplainerBig O Notation for Beginners: O(1), O(n), O(n squared), and O(log n) ExplainedBig O describes how an algorithm's work grows as input grows. Here is what O(1), O(n), O(n squared), and O(log n) mean and why the difference matters.ExplainerWhat Is UTF-8 and Unicode? Code Points, Byte Encoding, and Why UTF-8 WonUnicode assigns every character a code point; UTF-8 encodes those code points in one to four bytes. Here is how it works and why it beat the alternatives.ExplainerHow Subnet Masks Work: CIDR, Network Bits, and Usable HostsUnderstand how a subnet mask splits an IP address into network and host parts, what /24 means, and how to count usable hosts.How-toHow to Read Binary and Convert It to Decimal and HexLearn how binary place values work and convert binary to decimal and hexadecimal by hand, with clear worked examples.ExplainerOrdinal Numbers Explained: 1st, 2nd, 3rdOrdinal numbers show position, cardinal numbers show quantity. Learn the difference and how each language forms ordinals differently.