ASCII Table Reference

ASCII Table Reference | Online Free Tool | Elysia Tools

Tool usage guide

Learn when to use this tool, what it supports, and how real users apply it.

Key facts

Category: Development
Input types: checkbox, select
Output type: html
Sample coverage: 4
API ready: Yes

Overview

The ASCII Table Reference is an interactive lookup tool for the complete 7-bit ASCII character set (0–127). It provides instant access to decimal, hexadecimal, octal, binary, HTML entities, and control character representations, with built-in filtering and highlighting options to streamline development and debugging workflows.

When to use

When debugging low-level network protocols or serial communications where you need to map raw bytes to ASCII control characters.
When writing HTML or web content and you need to find the correct HTML entity or decimal code for special symbols.
When programming character validation logic and you need to verify the exact decimal or hex boundaries for uppercase, lowercase, or numeric ranges.

How it works

1Toggle the visibility of control characters (0–31, 127) or printable characters (32–126) to narrow down the displayed set.
2Apply a letter case filter to isolate uppercase letters, lowercase letters, digits, or punctuation and symbols.
3Select a highlight range to visually emphasize specific character groups like letters, digits, or control codes in the table.
4Read the corresponding decimal, hexadecimal, octal, binary, and HTML entity values directly from the generated interactive table.

Use cases

Finding the hexadecimal representation of control characters like Line Feed (LF) or Carriage Return (CR) for parser configuration.
Looking up HTML entity codes for symbols and punctuation to prevent rendering issues in web browsers.
Verifying binary and octal values of characters when writing low-level bitwise operations or embedded systems code.

Examples

1. Identifying Control Characters in Network Logs

Network Engineer

Background

A network engineer is analyzing raw packet payloads and encounters non-printable bytes like 0x0A and 0x0D.

Problem

They need to quickly identify which control characters these hex values represent.

How to use

Enable 'Show Control Characters', set the highlight range to 'Control', and locate the hex values 0A and 0D in the table.

Show Control Characters: enabled, Highlight Range: control

Outcome

The engineer identifies 0x0A as Line Feed (LF) and 0x0D as Carriage Return (CR), confirming the payload uses standard Windows-style line endings.

2. Validating Input Ranges for Form Fields

Frontend Developer

Background

A developer is writing a JavaScript keypress handler to restrict input to lowercase letters only.

Problem

They need to know the exact decimal range for lowercase letters (a-z) to set up boundary conditions.

How to use

Select 'Lowercase Letters' from the Letter Case Filter and check the decimal column for the start and end values.

FAQ

What is the range of characters covered by this ASCII table?

The table covers the standard 7-bit ASCII range from 0 to 127, including both control and printable characters.

Can I filter the table to show only numbers or letters?

Yes, you can use the Letter Case Filter to display only digits, uppercase letters, lowercase letters, or punctuation.

Does this tool support extended ASCII characters above 127?

No, this reference tool is strictly for the standard 7-bit ASCII character set (codes 0–127).

How do I find the HTML entity for a specific character?

Locate the character in the table to view its corresponding HTML entity representation in the dedicated column.

Can I hide control characters like NUL, LF, or CR?

Yes, uncheck the 'Show Control Characters' option to hide codes 0–31 and 127 from the table view.

Letter Case Filter: Lowercase Letters

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Learn when to use this tool, what it supports, and how real users apply it.

Key facts

Overview

When to use

How it works

Use cases

Examples

1. Identifying Control Characters in Network Logs

2. Validating Input Ranges for Form Fields

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