QR Code Generator
Generate QR codes for URLs, text, WiFi, vCard, email, SMS and phone — customize colors, size, error correction and logo overlay. Download as PNG or SVG.
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Barcode Generator
Generate Code128, EAN-13, UPC-A, Code39 and ITF-14 barcodes in your browser — customize width, height, colors and download as PNG.
2 worked examples
Methodology and sources included
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Reviewed April 27, 2026
Data
Barcode Generator is a free, browser-based data tool. Generate Code128, EAN-13, UPC-A, Code39 and ITF-14 barcodes in your browser — customize width, height, colors and download as PNG.
What this tool does
- Code128, EAN-13, UPC-A, Code39, ITF-14 formats
- custom bar width and height
- foreground and background colors
- show/hide text below barcode
- live preview
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A barcode generator renders a short string of data as a machine-readable barcode in any of the common symbologies — Code 128 for general purpose, EAN-13 for retail products, UPC-A for North American retail, Code 39 for industrial and military use, and ITF-14 for shipping cartons. Each symbology has its own allowed character set, check-digit rules, and minimum quiet-zone width, all defined by ISO/IEC 15420 and related standards. FastTool's generator implements the encoding math directly in the browser and produces SVG output, which scales losslessly to any print size — from a pharmacy label to a warehouse sign — without rasterisation artefacts.
Why This Matters
Barcodes still underpin a staggering amount of real-world logistics: every item in every grocery store, every package in every shipping network, every patient wristband in every hospital. Generating them correctly is a solved problem, but generating them wrong — incorrect check digit, wrong symbology, insufficient quiet zone — breaks scanners silently and creates cascading operational failures that take hours to trace back to a single bad label.
Real-World Case Studies
- Small-batch product launch. A maker preparing a first run of 500 units for a retail pilot generates
EAN-13barcodes from her GS1 prefix, prints them on labels, and runs the scan-test bulletin before shipping. Every label scans cleanly on the first pass. - Warehouse bin location. A logistics coordinator generates
Code 128labels for 2000 bin locations with alphanumeric IDs. The SVG output is scripted through a label printer, and the warehouse migrates from a hand-written pick-list to a scanner-driven workflow in a single weekend. - Event ticket check-in. A conference organizer generates unique
Code 128barcodes for 800 attendees, prints them on name badges, and uses a phone scanner at the door. Check-in throughput triples compared to the previous year's manual list.
Technical Deep Dive
Code 128 encodes data as pairs of alternating bars and spaces in three different character sets (A: uppercase + control, B: full ASCII, C: numeric pairs) with a modulo-103 check character. EAN-13 encodes 12 data digits plus a modulo-10 check digit using two distinct symbol sets that encode the hidden 13th digit via parity pattern — which is why European-region EAN-13 can represent values that UPC-A cannot. Every symbology requires a quiet zone (blank margin) of at least 10× the narrowest bar width, typically 2.5-5 mm, or scanners will fail to detect the start/stop pattern. Print resolution matters: the narrowest bar in Code 128 at retail size is about 0.33 mm, so anything under 300 DPI starts to blur. The generator enforces the quiet zone and warns when the data falls outside the symbology's allowed set.
💡 Expert Pro Tip
Always test print-scan before committing to a large run. The screen-rendered SVG looks perfect; the laser-printed version on a low-quality label stock might not. Print five, scan them with the exact device and angle your staff will use, and adjust module width or print resolution before ordering 10,000 labels.
Methodology, Sources & Accessibility
Methodology
The parsers and serialisers implement the published format specifications exactly. Strictness on input is intentional: a tool that is liberal about what it accepts masks bugs that break in a stricter downstream consumer. By producing strictly-correct output and rejecting clearly-invalid input, the tool acts as a sanity check for the rest of the pipeline.
Authoritative Sources
- RFC 4180 — CSV Format — The standard for comma-separated values.
- RFC 8259 — JSON — The standard format for JSON data interchange.
- YAML 1.2 Specification — The YAML configuration and data format specification.
- XML 1.0 Specification — The W3C XML specification.
- W3C Web Standards — The World Wide Web Consortium publishes HTML, CSS, DOM, and accessibility specifications that browser-based tools rely on.
About This Tool
Barcode Generator is a free, browser-based utility in the Data category. Generate Code128, EAN-13, UPC-A, Code39 and ITF-14 barcodes in your browser — customize width, height, colors and download as PNG. Standard processing runs on the client — no account is required, and there is no paywall or usage cap. The implementation uses audited standard-library primitives and published specifications rather than proprietary algorithms, so the output is reproducible and transparent.
Accessibility
FastTool targets WCAG 2.2 Level AA conformance: keyboard-navigable controls, visible focus states, semantic HTML, sufficient colour contrast, and screen-reader compatibility. If you encounter an accessibility issue, please reach us via the site footer.
Analysts and data professionals rely on Barcode Generator to generate Code128, EAN-13, UPC-A, Code39 and ITF-14 barcodes in your browser — customize width, height, colors and download as PNG without leaving the browser. Features such as Code128, EAN-13, UPC-A, Code39, ITF-14 formats and custom bar width and height are integrated directly into Barcode Generator, so you do not need separate tools for each step. Your data stays yours. Barcode Generator performs standard calculations and transformations locally, without requiring a server-based project workspace. Data professionals encounter format conversion and transformation challenges daily, whether during ETL pipelines, API integrations, or ad-hoc analysis tasks. Whether it is a one-time task or a recurring need, Barcode Generator is built to transform and process data faster. The typical workflow takes under a minute: open the page, paste or upload your data, review the output, and view, copy, or download the converted data. There is no learning curve and no configuration required for standard use cases. The interface is minimal: enter your input, get instant results, and view, copy, or download the converted data. Try Barcode Generator now — no sign-up required, and your first result is seconds away.
You might also like our Text to PDF Converter. Check out our JSON to CSV. For related tasks, try our CSV to JSON Converter.
Key Features of Barcode Generator
- Dedicated code128, ean-13, upc-a, code39, itf-14 formats functionality designed specifically for data use cases
- custom bar width and height — a purpose-built capability for data professionals
- foreground and background colors that saves you time by automating a common step in the process
- Barcode creation in standard formats for inventory and retail applications
- See changes in real time as you adjust settings
- Download your result directly to your device in the format you need
- Input validation that catches errors before processing
- Preset templates that give you a head start so you do not have to configure everything from scratch
- Advanced options for experienced users who need fine-grained control over the output
- One-click copy button to instantly transfer your result to the clipboard
- Completely free to use with no registration, no account, and no usage limits
- Runs in your browser for standard workflows, with no account or upload queue required
- Responsive design that works on desktops, tablets, and mobile phones
Why Use Barcode Generator?
- Reliable and always available — because Barcode Generator runs entirely in your browser with no server dependency, it works even when your internet connection is unstable. After the initial page load, you can disconnect completely and the tool continues to function without interruption.
- Speed that saves real time — Barcode Generator is designed to help you transform and process data faster as quickly as possible. The streamlined interface eliminates unnecessary steps, and instant local processing means you get your result in seconds rather than minutes.
- Privacy you can verify — unlike tools that merely promise privacy, Barcode Generator uses a client-side architecture that you can independently verify. Open your browser's Network tab and confirm: standard tool inputs are not intentionally sent to a FastTool application server during processing.
- Professional-quality output — Barcode Generator delivers results, including Code128, EAN-13, UPC-A, Code39, ITF-14 formats, custom bar width and height that meet professional standards. The output is clean, properly formatted, and ready to use in your projects, reports, or communications without additional cleanup.
Step-by-Step Guide
- Go to Barcode Generator on FastTool. No installation needed — it runs in your browser.
- Start by adding your content — paste or upload your data. The tool supports Code128, EAN-13, UPC-A, Code39, ITF-14 formats for added convenience. Clear field labels ensure you know exactly what to provide.
- Fine-tune your output using options like custom bar width and height and foreground and background colors. These controls let you customize the result for your specific scenario.
- Click the action button to process your input. Results appear instantly because everything runs client-side.
- Your output appears immediately in the result area. Take a moment to review it and make sure it matches what you need before proceeding.
- Export your result by clicking the copy button or using your browser's built-in copy functionality. The tool makes it easy to view, copy, or download the converted data with minimal effort.
- Run the tool again with new data whenever you need to. Barcode Generator has no usage caps, so you can process as many inputs as your workflow requires.
Tips from Power Users
- When migrating between systems, use Barcode Generator to create sample data in the target format. This lets you test the import process before committing to the full dataset.
- Validate your output against the target schema or specification. Format conversion tools handle the syntax, but you still need to verify semantic correctness.
- Set up a repeatable workflow: input file, tool, output file. If you do the same transformation regularly, knowing the exact steps reduces the chance of errors.
Common Errors and Fixes
- Running a transformation on the original dataset with no backup. Even when the tool is non-destructive, habit is protection — always work on a copy so a misread column never becomes a permanent loss.
- Ignoring subtle encoding or locale issues. A CSV that works in the US (commas, period decimals) can break in Europe (semicolons, comma decimals) — always verify the target consumer's locale.
- Skipping row-count sanity checks. Compare input vs output record counts after every transformation; silent row loss is one of the most common and most damaging data pipeline bugs.
- Using Barcode Generator output as the authoritative source instead of a working copy. Always preserve the provenance chain — source system, transformation, destination — so you can audit the result later.
- Trusting automatic type inference. Numeric IDs, postal codes, and phone numbers often get coerced into numbers, silently losing leading zeros — explicit typing beats clever guessing every time.
See Barcode Generator in Action
Generating a Code 128 barcode
Input
Data: ABC-12345
→
Output
[Barcode Image — Code 128 encoding 'ABC-12345']
Code 128 supports all ASCII characters, making it versatile for shipping labels, inventory, and asset tracking.
Generating an EAN-13 barcode
Input
Data: 5901234123457
→
Output
[Barcode Image — EAN-13 with check digit verified]
EAN-13 is the international standard for retail products. The 13th digit is a check digit calculated from the first 12.
Why Choose Barcode Generator
| Feature | Browser-Based (FastTool) | Mobile App | Server-Based Tool |
|---|---|---|---|
| Cost | Free, no limits | $$$ license fee | Free tier + paid plans |
| Privacy | Browser-local standard processing | Local processing | Data uploaded to servers |
| Installation | None — runs in browser | Download + install | Account creation required |
| Updates | Always latest version | Manual updates needed | Automatic but may break |
| Device Support | Any device with browser | Specific OS only | Browser but needs login |
| Offline Use | After initial page load | Full offline support | Requires internet |
When to Reach for a Different Approach
No tool is perfect for every scenario. Here are situations where a different approach will serve you better:
- When the data must stay within a regulated environment. HIPAA, GDPR Article 9 data, or classified material should never leave a sanctioned system — use the designated internal tooling.
- When you need auditable, repeatable pipelines. A dbt model, Airflow DAG, or versioned SQL script produces reproducible transformations that a browser session cannot match.
- When multiple analysts need to share state. Browser tools do not sync; a shared warehouse or notebook environment is the right collaboration surface for team analytics.
The History of Barcode Systems
The barcode was conceptualized in 1948 by Norman Woodland, who drew four lines in the sand at a Miami beach, extending Morse code into visual form. The first commercial barcode scan occurred on June 26, 1974, when a pack of Wrigley's Juicy Fruit gum was scanned at a Marsh supermarket in Troy, Ohio using the UPC (Universal Product Code) system. Code 39, one of the most widely used barcode formats, encodes 43 characters (A-Z, 0-9, and seven special characters) using patterns of narrow and wide bars and spaces, with each character represented by nine elements (five bars and four spaces), three of which are wide — hence the name Code '3 of 9.'
Different barcode symbologies serve different purposes. UPC-A and EAN-13 are standard for retail products worldwide. Code 128 is used in shipping and logistics because it supports the full ASCII character set with high data density. Code 39 is popular in manufacturing and government because it is self-checking (no required check digit) and can be printed by standard laser printers. 2D barcodes like QR codes and Data Matrix can store much more information than 1D barcodes — up to several thousand characters versus typically 20-25 characters — and can be read from any orientation.
How Barcode Generator Works
Barcode Generator implements industry-standard parsing algorithms in client-side JavaScript with capabilities including Code128, EAN-13, UPC-A, Code39, ITF-14 formats, custom bar width and height, foreground and background colors. The tool supports multiple data formats through modular parsers, each validated against the relevant specification (RFC 4180 for CSV, RFC 8259 for JSON, YAML 1.2 for YAML). Error reporting includes line numbers and descriptions to help you fix issues quickly. All processing runs locally, making it safe for sensitive or proprietary data.
Worth Knowing
JSON has become the most common API data format, used by over 70% of public web APIs, largely replacing XML for data interchange.
The Parquet file format, widely used in big data, can compress data to 2-10% of its raw size while maintaining full query capability.
Glossary
- Data Pipeline
- A series of processing steps that move and transform data from one system to another. Each step in the pipeline handles a specific operation like cleaning, converting, or validating.
- Data Normalization
- The process of organizing data to reduce redundancy and improve integrity. In databases, normalization follows specific forms (1NF, 2NF, 3NF) that progressively eliminate data anomalies.
- Parsing
- The process of analyzing a string of symbols according to the rules of a formal grammar. Parsers convert raw text into structured data that programs can work with.
- Character Encoding
- A system that maps characters (letters, numbers, symbols) to numerical values that computers can store and process. UTF-8, ASCII, and ISO-8859-1 are widely used encodings.
Got Questions?
What barcode format should I use?
This is a common question about Barcode Generator. Generate Code128, EAN-13, UPC-A, Code39 and ITF-14 barcodes in your browser — customize width, height, colors and download as PNG. The tool features Code128, EAN-13, UPC-A, Code39, ITF-14 formats, custom bar width and height, foreground and background colors and runs entirely client-side for maximum privacy. It is one of 902 free tools on FastTool, focused on data processing, conversion, and analysis.
What is Code128 barcode?
In the context of data, Code128 barcode refers to a fundamental concept that professionals and learners encounter regularly. Barcode Generator provides a free, browser-based way to work with Code128 barcode: generate code128, ean-13, upc-a, code39 and itf-14 barcodes in your browser — customize width, height, colors and download as png.. The tool offers Code128, EAN-13, UPC-A, Code39, ITF-14 formats, custom bar width and height, foreground and background colors and processes standard inputs locally in your browser.
Check out: QR Code Generator
What is EAN-13 barcode format?
In the context of data, EAN-13 barcode format refers to a fundamental concept that professionals and learners encounter regularly. Barcode Generator provides a free, browser-based way to work with EAN-13 barcode format: generate code128, ean-13, upc-a, code39 and itf-14 barcodes in your browser — customize width, height, colors and download as png.. The tool offers Code128, EAN-13, UPC-A, Code39, ITF-14 formats, custom bar width and height, foreground and background colors and processes standard inputs locally in your browser.
What is UPC-A barcode?
In the context of data, UPC-A barcode refers to a fundamental concept that professionals and learners encounter regularly. Barcode Generator provides a free, browser-based way to work with UPC-A barcode: generate code128, ean-13, upc-a, code39 and itf-14 barcodes in your browser — customize width, height, colors and download as png.. The tool offers Code128, EAN-13, UPC-A, Code39, ITF-14 formats, custom bar width and height, foreground and background colors and processes standard inputs locally in your browser.
You might also find useful: Text to PDF Converter
How do I create ITF-14 barcodes?
To create ITF-14 barcodes, open Barcode Generator on FastTool and paste or upload your data. The tool is designed to make this process simple: generate code128, ean-13, upc-a, code39 and itf-14 barcodes in your browser — customize width, height, colors and download as png.. Use the available options — including Code128, EAN-13, UPC-A, Code39, ITF-14 formats, custom bar width and height, foreground and background colors — to fine-tune the result. The standard workflow runs in your browser, with no FastTool account or project upload required.
What is Barcode Generator?
Barcode Generator is a purpose-built data utility designed for analysts and data professionals. Generate Code128, EAN-13, UPC-A, Code39 and ITF-14 barcodes in your browser — customize width, height, colors and download as PNG. The tool features Code128, EAN-13, UPC-A, Code39, ITF-14 formats, custom bar width and height, foreground and background colors, all running locally in your browser. There is no server involved and nothing to install — open the page and you are ready to go.
Check out: JSON to CSV
How to use Barcode Generator online?
To get started with Barcode Generator, simply open the tool and paste or upload your data. The interface guides you through each step with clear labels and defaults. After processing, you can view, copy, or download the converted data. No registration or downloads required — everything is handled client-side.
Does Barcode Generator work offline?
Once the page finishes loading, Barcode Generator works without an internet connection. All computation runs locally in your browser using JavaScript, so there are no server requests during normal operation. Feel free to disconnect after the initial load — your workflow will not be affected. Bookmark the page so you can reach it quickly the next time you are online, and the tool will be ready to use again as soon as the page loads.
You might also find useful: CSV to JSON Converter
What makes Barcode Generator stand out from similar tools?
Barcode Generator combines a browser-first workflow, speed, and zero cost in a way that most alternatives simply cannot match. Server-based tools introduce network latency and additional data handling because work passes through third-party infrastructure. Barcode Generator reduces both problems by keeping standard processing directly in your browser. Results appear instantly, and there is no subscription, no free trial expiration, and no feature gating to worry about.
What languages does Barcode Generator support?
You can use Barcode Generator in any of 21 supported languages. The tool uses a client-side translation system that updates the entire interface without requiring a page reload, so switching languages is instant and does not interrupt your work. Full support for right-to-left scripts like Arabic and Urdu is included, with proper layout mirroring. The supported languages span major regions across Europe, Asia, the Middle East, and South America.
Check out: Excel to JSON
Do I need to create an account to use Barcode Generator?
You do not need an account for Barcode Generator or any other tool on FastTool. Everything is accessible instantly and anonymously, with no registration barrier of any kind. Your data and usage are never tied to an identity, which also means there is nothing to manage, no passwords to remember, and no risk of your account credentials being exposed in a data breach.
When to Use Barcode Generator
Interoperability
Convert data between formats using Barcode Generator to ensure compatibility between different applications and services. Because Barcode Generator runs entirely in your browser, you maintain full control over your data throughout the process, which is especially important when working with sensitive or proprietary information.
Data Quality Audits
Run quick data quality checks with Barcode Generator to catch formatting issues, duplicates, or inconsistencies before they reach production. The zero-cost, zero-setup nature of Barcode Generator makes it ideal for this scenario — you get professional-quality results without committing to a software purchase or subscription.
Spreadsheet Workflows
Use Barcode Generator to prepare data for import into Excel or Google Sheets, handling the transformation step in your browser. The zero-cost, zero-setup nature of Barcode Generator makes it ideal for this scenario — you get professional-quality results without committing to a software purchase or subscription.
Log Analysis
Parse and transform log files with Barcode Generator to extract the information you need without installing command-line tools. Since there are no usage limits, you can repeat this workflow as many times as needed, experimenting with different inputs and settings until you achieve the exact result you want.
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References & Further Reading
Authoritative sources and official specifications that back the information on this page.
- ISO/IEC 15420 - EAN/UPC bar code symbology — ISO
Authoritative EAN/UPC spec
- Barcode - Wikipedia — Wikipedia
Background
- GS1 - Barcodes — GS1
Official barcode standards body