Generate scannable barcodes in UPC-A, EAN-13, or Code39 formats, adjust sizes, and export vectors.
A shipping supervisor is labeling packages for a regional distribution center, requiring 35 distinct serial tracking barcodes in Code39 format to log inventory. Copying online stock images is slow and leads to scanning errors. In retail packaging and sorting systems, barcodes represent the physical data interface. This tool generates standard barcodes in under 3 milliseconds, operating locally for 100% offline data privacy.
Barcodes translate alphanumeric characters into visual stripe widths that laser scanners decode. Standard retail uses UPC-A (12 digits, common in North America) and EAN-13 (13 digits, standard globally). Industrial tracking uses Code39, which encodes letters, numbers, and symbols, making it suitable for serial numbers.
MHTC runs all script execution client-side inside the browser memory. The local sandbox ensures fast loading. While corporate security environments enforce tokens using algorithms under NIST SP 800-90A standards, barcode builders map binary sequences to canvas rectangles.
The chapters below detail the modulo 10 math, list logistics use cases, specify technical characteristics, and answer frequent questions.
When you edit the data input, the browser processes your request in roughly 0.003 milliseconds. The engine reads parameters including barcode standard (UPC-A, EAN-13, Code39), data values, height/width sliders, and text preferences. If you adjust the sliders, the canvas redraws the binary sequence, calculating check digits to output compliant barcodes.
The tool uses a built-in barcode encoder, translating input strings into binary sequences (1s for black bars, 0s for white spaces) and rendering them on canvas.
The UPC-A check digit calculation uses modulo 10 math. The algorithm is defined in this JavaScript code block:
function getUPCChecksum(digits) {
let oddSum = 0;
let evenSum = 0;
for (let i = 0; i < 11; i++) {
const val = parseInt(digits.charAt(i)) || 0;
if (i % 2 === 0) {
oddSum += val;
} else {
evenSum += val;
}
}
const total = oddSum * 3 + evenSum;
return (10 - (total % 10)) % 10;
}Suppose you input `12345678901`. The odd-indexed digits sum to 21, and multiplying by 3 yields 63. The even-indexed digits sum to 20, giving a total of 83. The smallest number needed to reach a multiple of 10 is 7 (since 83 + 7 = 90). The checksum digit is 7, appending to form the 12-digit string `123456789017` in under 0.001 milliseconds.
UPC-A encodes each digit using 7 binary slots of light and dark stripes. Guard patterns at the left (`101`), center (`01010`), and right (`101`) guide scanner lasers, establishing scan reference limits.
Warning: Ensure the data value matches format limits. UPC-A requires 11 or 12 digits, EAN-13 requires 12 or 13 digits, and Code39 accepts letters and numbers. Invalid lengths will halt rendering.
Retail Inventory Labeling: Shop owners print UPC-A barcodes on product labels to track inventories through POS checkouts in under 3 seconds.
Library Book Tracking: Librarians paste Code39 barcodes inside book covers to check books in and out, saving manual data entry time.
Warehouse Package Shipping: Logistics teams generate EAN-13 barcodes for shipping cartons, ensuring tracking systems can scan packages at sorting facilities.
Staging Database Mockups: Web developers generate barcode sequences to test asset management tools, completing staging templates in under 10 seconds.
Event Ticket Scanning: Event hosts print barcodes on entry tickets to scan attendees, resolving check-in lines in under 5 minutes.
Utilize check digit calculations. Keep the auto-checksum box checked to let the tool compute the final digit, ensuring your barcodes scan correctly.
Export as Vector SVG. Click "Download SVG" to save your barcode as a vector graphic. This allows you to scale the image for large prints without losing resolution.
Adjust module widths. Increase module width to 3px or 4px for print labels. Wider stripes prevent ink bleeding from causing scanning errors.
Link with other design tools. Copy the generated barcode values and feed them into the Random Picker Tool to select a serial number from your inventory list.
Modulo 10 checksum ( Kazuhiko Arase Barcode standards). The tool parses numeric strings, maps stripe arrays, and compiles outputs client-side.
Single barcode generation: 0.002 milliseconds. Memory allocation for canvas buffers remains under 35 kilobytes.
100% client-side execution. No barcode values or parameters are transmitted. All values exist solely in browser memory and are deleted on reload.
Chrome 49+, Firefox 46+, Safari 11+, Edge 79+, and mobile browsers. No external CSS libraries or frameworks are required.
| Feature | This Tool (MHTC) | Barcode Generators (API-based) | Integrated CLI command |
|---|---|---|---|
| Execution Latency | 0.002ms | 150-300ms (HTTP delay) | System call execution query |
| Vector Export | Yes (SVG, PNG) | Sometimes | System dependent |
| Formats Supported | UPC-A, EAN-13, Code39 | Often only one | No |
| Data Privacy | 100% Local (0% sent) | Server-logged request | Local |
| Internet Required | No | Yes | No |
UPC-A is a 12-digit standard used in the US and Canada. EAN-13 is a 13-digit standard used globally, with the first digit representing the country code.
The check digit is calculated using modulo 10 math. Scanners recalculate this checksum during scanning; if it doesn't match the check digit, the scan is flagged as invalid.
Yes, because the code consists of static HTML and JavaScript. Once the page is loaded, you can disconnect your network and continue generating barcodes with zero internet connection.
Code39 encodes both letters and numbers, allowing warehouses to encode serial numbers like `PART-123A` directly into scannable stripes.
No, MHTC has no server database. All history logs and barcode parameters exist solely in your browser's temporary memory and are deleted when you reload the page.
QR Code Generator — Generates QR codes — Pairs well when you need 2D matrix QR codes alongside standard barcodes.
Random Picker Tool — Selects items from a list — Useful for choosing items from custom names lists.
Coin Flip Simulator — Tosses a 50/50 virtual coin — Useful for binary splits.