What is a .SCH File? Schematic File Formats Compared

You’ve downloaded a reference design, opened a folder of design files, and found a .SCH file. Now what? The frustrating reality is that .SCH is one of the most overloaded file extensions in electronics design—used by EAGLE, KiCad (legacy versions), OrCAD, ExpressSCH, TINA, gEDA, and several other EDA tools, each with completely different internal formats.

This guide explains what .SCH files are, how to identify which program created your file, and how to open or convert schematic files between different EDA platforms.

What is a .SCH File?

A .SCH file is a schematic document containing the logical design of an electronic circuit. It stores component symbols, electrical connections (wires), net labels, power ports, and design parameters that define how components connect to form a working circuit.

The problem? At least ten different EDA programs use the .SCH extension, and their file formats are completely incompatible with each other. A .SCH file from EAGLE won’t open in ExpressSCH, and a KiCad legacy .SCH file won’t work in OrCAD. Before you can open a .SCH file, you need to identify which program created it.

Common .SCH File Types

How to Identify Your .SCH File Type

The quickest way to identify which program created a .SCH file is to open it in a text editor like Notepad++ or VS Code. The first few lines reveal the format immediately.

Identification by File Header

If the file opens as readable text, you can usually identify the format. If it shows binary garbage, you’re dealing with a proprietary binary format that requires the original application to open.

EAGLE .SCH Files

EAGLE (now part of Autodesk Fusion 360) is one of the most common sources of .SCH files, particularly in hobbyist and Arduino communities.

EAGLE Format Versions

Modern EAGLE .SCH files (version 6 and later) use XML format, making them readable in any text editor and importable by other EDA tools. The XML structure includes component definitions, wire connections, and sheet properties in a hierarchical format.

EAGLE .SCH File Structure

xml

<?xml version=”1.0″ encoding=”utf-8″?><!DOCTYPE eagle SYSTEM “eagle.dtd”><eagle version=”9.6.2″>  <drawing>    <settings>      <setting alwaysvectorfont=”no”/>      <setting verticaltext=”up”/>    </settings>    <grid distance=”0.1″ unitdist=”inch”/>    <layers>      <!– layer definitions –>    </layers>    <schematic>      <!– schematic content –>    </schematic>  </drawing></eagle>

KiCad Legacy .SCH Files

KiCad used the .SCH extension for schematic files through version 5.x. Starting with KiCad 6.0, the new S-expression format uses the .kicad_sch extension instead.

KiCad Schematic Format History

KiCad Legacy .SCH Structure

EESchema Schematic File Version 4EELAYER 30 0EELAYER END$Descr A4 11693 8268encoding utf-8Sheet 1 1Title “My Schematic”Date “2023-01-15″Rev “1.0”Comp “”$EndDescr$CompL Device:R R1U 1 1 5F8A1234P 3500 2500F 0 “R1” H 3570 2546 50 0000 L CNNF 1 “10k” H 3570 2455 50 0000 L CNN$EndCompWire Wire Line 3500 2350 3500 2200$EndSCHEMATC

Legacy KiCad .SCH files are plain ASCII text with a clear structure—coordinates in mils (1/1000 inch), component definitions between $Comp and $EndComp tags, and wires defined by coordinate pairs.

OrCAD and Other Binary .SCH Formats

Several programs use binary formats for their .SCH files, making them unreadable without the original software.

Binary .SCH Format Programs

For binary .SCH files, you typically need either:

• The original software that created the file
• A conversion tool specific to that format
• Export the file to a common interchange format from the original software

How to Open .SCH Files

Opening a .SCH file requires matching the file format to compatible software.

Software Compatibility Matrix

Opening EAGLE .SCH Files

In EAGLE/Fusion 360:

1. File → Open → Select the .sch file
2. Works with all EAGLE versions

In KiCad:

1. File → Import Non-KiCad Project → EAGLE Project
2. Select the EAGLE .sch file
3. KiCad imports both schematic and associated board

In EasyEDA:

1. File → Open → EAGLE
2. Select the .sch file (must be XML format)

Opening KiCad Legacy .SCH Files

In KiCad 6+:

1. File → Open Project
2. Select the project or .sch file
3. KiCad automatically converts to new format

In KiCad 5.x:

1. Native open via File → Open
2. No conversion needed

Read more PCB Files format:

What are .GBR and .PHO Files? Gerber File Extensions Guide

What are PCB Panelization Files? Complete Array Format Guide

What is .DSN File? Specctra Autorouter Format Explained

What is .kicad_pcb? KiCad PCB File Format Guide

What is .PcbDoc? Altium Designer PCB Format Explained

What is .PrjPcb? Altium Designer Project File Explained

What is .SchDoc? Altium Schematic File Explained

What is a .ASC File? PADS ASCII Format Explained

What is a .BRD File? Eagle PCB File Format Explained

What is a .DRC File? Design Rule Check Reports Explained

What is a .PCB File? Complete Protel/Altium PCB Format Guide

What is a .SES File? Complete Specctra Session File Guide for PCB Engineers

What is a BOM File? Bill of Materials Format for PCB Assembly

What is a CPL File? SMT Component Placement Guide

What is a Fabrication Drawing? PCB Fab Notes Explained

What is a Gerber Job File? Project Metadata Explained

What is a Netlist? PCB Connectivity Data Explained

What is a Pick and Place File? SMT Centroid Data Guide

What is a Stencil Gerber File? Complete Solder Paste Stencil Guide

What is an Aperture File? Gerber Tool Definition Guide

What is an Assembly Drawing? Complete PCB Assembly Documentation Guide

What is DXF in PCB Design? CAD Drawing Exchange Format Explained

What is Excellon? NC Drill File Format for PCB Manufacturing

What is GenCAD? Universal PCB Data Format Explained

What is Gerber RS-274X? The PCB Industry Standard Explained

What is Gerber X2? The Modern Gerber Format Guide

What is Gerber X3? Component Data in Gerber Files

What is HPGL? PCB Plotter File Format Guide

What is IGES? 3D PCB Model Format Explained

What is ODB++? Complete PCB Data Exchange Format Guide

What is PDF/A for PCB? Documentation Standards Guide

What is STEP File in PCB Design? 3D Model Exchange Guide

What is VRML in PCB? 3D Visualization Format Guide

Converting .SCH Files Between Formats

Converting schematic files between formats is often necessary when migrating between EDA tools or collaborating with engineers using different software.

Conversion Paths

Online Conversion Tools

Conversion Best Practices

When converting .SCH files between formats:

1. Verify component mappings: Symbol libraries differ between tools—ensure all components map correctly
2. Check connections: Confirm all wires and nets transferred properly
3. Review hierarchical sheets: Multi-sheet designs may need manual reconnection
4. Run ERC: Electrical Rules Check catches conversion errors
5. Compare visually: Open both original and converted files side-by-side

.SCH vs Other Schematic Extensions

Understanding alternative schematic file extensions helps when working across different EDA ecosystems.

Schematic File Extension Comparison

When to Use Each Format

Troubleshooting .SCH File Issues

Common problems when working with .SCH files and their solutions.

Problem Resolution Guide

Useful Resources for .SCH Files

Software Downloads

Conversion and Viewing Tools

Documentation

Frequently Asked Questions About .SCH Files

How do I know which program created my .SCH file?

Open the .SCH file in a text editor like Notepad++ or VS Code. If the file is readable text, look at the first few lines. EAGLE XML files start with <?xml, KiCad legacy files start with EESchema Schematic File Version, and gEDA files start with v followed by a date. If the file shows binary garbage (random characters), it’s likely from OrCAD, ExpressSCH, or an older EAGLE version, and you’ll need the original software to open it.

Can KiCad open EAGLE .SCH files?

Yes, KiCad 7 and later can import EAGLE .SCH files directly through File → Import Non-KiCad Project → EAGLE Project. However, this only works with EAGLE XML format files (version 6.0 and later). Binary EAGLE files from earlier versions must first be opened in EAGLE and saved in XML format, or exported as EAGLE 7.x legacy format. KiCad will import both the schematic and associated board file together.

Why won’t my .SCH file open in any program?

The .SCH extension is used by many different programs with incompatible formats. If your file won’t open, you’re likely trying to use the wrong software. First identify the file format using a text editor, then obtain the correct software. If the file is from ExpressSCH, you must use ExpressSCH—there’s no conversion path available. For OrCAD files, you need OrCAD Capture or Altium Designer’s import function.

How do I convert .SCH files to PDF for sharing?

The most reliable method is opening the .SCH file in its native application and using File → Print or File → Export to create a PDF. Most EDA tools include PDF export functionality. If you don’t have the original software, try importing into a compatible tool first (like importing EAGLE into KiCad), then export to PDF from there. Online tools like Schematics.io can also convert some .SCH formats to image files.

What’s the difference between .SCH and .kicad_sch files?

The .SCH extension was used by KiCad through version 5.x and used a simple ASCII format with components and wires defined in a flat text structure. Starting with KiCad 6.0, the new .kicad_sch extension uses S-expression format (nested parenthetical syntax similar to Lisp), which is more structured and supports advanced features like embedded symbols and better hierarchical design handling. KiCad 6+ can open legacy .SCH files and automatically converts them to the new format.

Conclusion

The .SCH extension’s use across multiple incompatible EDA tools makes it one of the most confusing file types in electronics design. The key to working with .SCH files is identification—once you know which program created the file, you can choose the appropriate software to open it or find a conversion path to your preferred tool.

For new projects, consider using formats with better interoperability: KiCad’s .kicad_sch format is open and well-documented, EAGLE’s XML format is widely importable, and Altium’s ASCII .SchDoc option provides broad third-party tool support. When sharing designs, including a PDF export alongside native files ensures anyone can at least view the schematic regardless of their software.

The EDA landscape continues evolving, with tools like KiCad adding better import capabilities for proprietary formats. Check your specific tool’s current import options—today’s incompatible format may become tomorrow’s seamless import.