ReasonableRTF.Standard 2026.7.0

ReasonableRTF - Fast RTF to Plain Text Converter 🚀

A lightweight and performant C# library designed for rapidly converting Rich Text Format (RTF) files into plain text.

Features

• Fast: Up to 400x faster than RichTextBox — and over 100x faster at minimum
• Accurate: All characters converted correctly — even Wingdings
• Fully cross-platform
• Can read from forward-only streams such as DeflateStream
• We even support this obscure nonsense

Installation

Install the library via NuGet:

dotnet add package ReasonableRTF.Standard

Quick Start

Converting An RTF File

Use the static ConvertRtf.ToText() method to do a one-off conversion:

using ReasonableRTF;
using ReasonableRTF.Enums;
using ReasonableRTF.Models;

// ...

RtfResult result = ConvertRtf.ToText(@"C:\rtf_files\some_file.rtf");

if (result.Error == RtfError.OK)
{
    // Conversion was successful
    string plainText = result.Text;
    Console.WriteLine("Converted Text:\n" + plainText);
}
else
{
    // Handle conversion errors
    Console.WriteLine($"Conversion Error: {result.Error} at byte position: {result.BytePositionOfError}");
    if (result.Exception != null)
    {
        Console.WriteLine($"Exception Details: {result.Exception.Message}");
    }
}

Converting Many RTF Files Efficiently

You can create and reuse an RtfToTextConverter instance to minimize overhead when converting many files:

using ReasonableRTF;
using ReasonableRTF.Enums;
using ReasonableRTF.Models;

// ...

RtfToTextConverter converter = new RtfToTextConverter();
foreach (string fileName in Directory.EnumerateFiles(@"C:\rtf_files\", "*.rtf"))
{
    RtfResult result = converter.Convert(fileName);
    if (result.Error == RtfError.OK)
    {
        // Conversion was successful
        string plainText = result.Text;
        Console.WriteLine("Converted Text:\n" + plainText);
    }
    else
    {
        // Handle conversion errors
        Console.WriteLine($"Conversion Error: {result.Error} at byte position: {result.BytePositionOfError}");
        if (result.Exception != null)
        {
            Console.WriteLine($"Exception Details: {result.Exception.Message}");
        }
    }
}

For efficiency, an RtfToTextConverter will not trim its internal growable buffers between conversions. You can use the ResetMemory() method to reset these buffers back to their default sizes. This way, you can keep one RtfToTextConverter instance around indefinitely without worrying about memory use.

The RtfResult Struct

The RtfResult struct provides full details about the conversion process, ensuring you can robustly handle success and failure cases.

Conversion Options

For more control over the output, you can provide an instance of the RtfToTextConverterOptions class.

RtfToTextConverterOptions options = new RtfToTextConverterOptions
{
    ConvertHiddenText = true,          // Include text marked as hidden
    LineBreakStyle = LineBreakStyle.LF // Use Unix-style line breaks
};

RtfResult result = ConvertRtf.ToText(@"C:\rtf_files\some_file.rtf", options);
// ... check result

The available options are documented in RtfToTextConverterOptions.cs.

Benchmarks

.NET 10 64-bit

BenchmarkDotNet v0.15.8, Windows 11 (10.0.26200.8655/25H2/2025Update/HudsonValley2)
AMD Ryzen 5 5600 3.50GHz, 1 CPU, 12 logical and 6 physical cores
.NET SDK 10.0.301
  [Host]     : .NET 10.0.9 (10.0.9, 10.0.926.27113), X64 RyuJIT x86-64-v3
  DefaultJob : .NET 10.0.9 (10.0.9, 10.0.926.27113), X64 RyuJIT x86-64-v3

.NET Framework 4.8 64-bit

BenchmarkDotNet v0.15.8, Windows 11 (10.0.26200.8655/25H2/2025Update/HudsonValley2)
AMD Ryzen 5 5600 3.50GHz, 1 CPU, 12 logical and 6 physical cores
  [Host]     : .NET Framework 4.8.1 (4.8.9337.0), X64 RyuJIT VectorSize=256
  DefaultJob : .NET Framework 4.8.1 (4.8.9337.0), X64 RyuJIT VectorSize=256

.NET Framework 4.8 32-bit

BenchmarkDotNet v0.15.8, Windows 11 (10.0.26200.8655/25H2/2025Update/HudsonValley2)
AMD Ryzen 5 5600 3.50GHz, 1 CPU, 12 logical and 6 physical cores
  [Host]     : .NET Framework 4.8.1 (4.8.9337.0), X86 LegacyJIT
  DefaultJob : .NET Framework 4.8.1 (4.8.9337.0), X86 LegacyJIT

Supported RTF features

Supported

• All basic plain text, hex-encoded chars, Unicode-encoded chars
• Symbol fonts (Wingdings 1, 2 and 3, Webdings, Symbol, and Zapf Dingbats) converted to Unicode equivalents
• Characters specified as "SYMBOL" field instructions
• Undocumented use of the \langN keyword to specify character encoding - old versions of RichTextBox used to support this

Partially supported

• Tables: Cells and rows have spaces between them, but not much functionality beyond that.
• Lists: Numbers and bullets show up (that's better than RichTextBox most of the time), but indentation usually doesn't.

Not currently supported

• Footnotes
• "HYPERLINK" field instruction value
• Math objects

License and Attribution

Code License

The original code for this RTF converter was written by Brian Tobin and is licensed under the MIT License (Copyright 2024-2026 Brian Tobin). For the full license text, please refer to the LICENSE file ReasonableRTF.

Flamifly contributed to the readme (installation, quick start, documentation, etc), and ported the original .NET-only version to .NET Standard.