Barcode Generator: Code 128, Code 39, QR & UPC

Type a value and the barcode draws as you type. SKU-88421 in Code 128 is 11 symbol characters with check character 68, 47.2 mm (1.86 in) wide at a 0.33 mm bar.

Preview scaled to fit. Downloads keep the true size.

Your barcode Code 128 SKU-88421

Encoded asSet B → C

Check68 (mod 103)

Printed width47.2 mm · 1.86 in

Label fitFits a 2 in label

Value to encode

Symbology

Code 128 set

Narrow bar, X (mm)

Bar height (mm)

Label width

Text under bars

Download as

The barcodes are drawn in your browser. Quiet zones are included in every width.

How to

How to Make a Barcode in 3 Steps

Pick the symbology your scanner or partner expects. Code 128 for your own SKUs, bins and cartons. UPC-A or EAN-13 for retail. QR for a URL or text.
Type the value, or paste a list. Check digits and check characters are calculated for you. A wrong retail check digit is flagged before anything prints.
Set the bar width and download. Choose the label width and the tool shows whether the barcode fits, with quiet zones counted.

Symbology	What it encodes	Length	Check	Quiet zone used here
Code 128	All 128 ASCII characters	Variable	Mod 103, always	10 X each side
Code 39	0–9, A–Z, space, - . $ / + %	Variable	Mod 43, optional	10 X each side
QR Code	Any text, URLs, UTF-8	Variable	Reed-Solomon, L to H	4 modules each side
UPC-A	12 digits	Fixed	GS1 mod 10	9 X each side
EAN-13	13 digits	Fixed	GS1 mod 10	11 X left, 7 X right
EAN-8	8 digits	Fixed	GS1 mod 10	7 X each side
ITF-14	14 digits	Fixed	GS1 mod 10	10 X each side
Interleaved 2 of 5	Digits, in pairs	Even count	None built in	10 X each side

Bulk

Bulk Barcode Generator: Lists and Sequences

Switch to Bulk list to turn a spreadsheet column, or a numbered run, into up to 250 barcodes in one pass. Each line is checked on its own.

Paste a column

One value per line. Add a caption after a vertical bar, such as SKU-88421 | Blue tee, M. The caption prints under the barcode on the sheet.

Build a sequence

Give a prefix, a start number, a count and the digits to zero-pad to. The list fills with every value in order.

Skip, do not stop

A line that cannot be encoded is listed with its reason. Every other line still renders and downloads.

Use	Prefix · start · count · pad	First	Last	Code 128 path (last)	Width at 0.33 mm
Bin locations	`A12-R04-B` · 1 · 24 · 2	`A12-R04-B01`	`A12-R04-B24`	Set B	58.1 mm
Carton IDs	`CTN-2026-` · 1 · 250 · 6	`CTN-2026-000001`	`CTN-2026-000250`	Set B → C	65.3 mm
Asset tags	`ASSET-` · 1001 · 50 · 0	`ASSET-1001`	`ASSET-1050`	Set B → C	50.8 mm
Tote numbers	`T` · 1 · 120 · 4	`T0001`	`T0120`	Set B → C	32.7 mm

Zero padding keeps every value the same length, so a run of labels shares one width and sorts correctly in a spreadsheet.

Code 128

Code 128 Barcode Generator: Sets A, B and C

Code 128 switches between three character sets inside one barcode. Set C packs two digits into one symbol character, which is why numbers come out narrow.

Set A

Digits, upper case, punctuation and control characters. Needed only when a system expects control codes.

Set B

Digits, upper and lower case, and full punctuation. The usual set for SKUs with letters.

Set C

Digit pairs 00–99. Auto mode switches to it for 4+ digits at the start or end, or 6+ in the middle.

Value	Auto encodes as	Symbol characters	Check character	Width, auto	Width, set B only
`SKU-88421`	Set B → C	11	68	47.2 mm	50.8 mm
`A12-R04-B01`	Set B	14	78	58.1 mm	58.1 mm
`PO 2026-000418`	Set B → C	15	61	61.7 mm	69.0 mm
`100045678912`	Set C	9	5	39.9 mm	61.7 mm
`0012345678905`	Set C → B	11	90	47.2 mm	65.3 mm

Widths at X = 0.33 mm with 10 X quiet zones. For the 12-digit 100045678912, auto is 35% narrower than set B.

How the mod 103 check character is calculated

Take the start code value, add each data value multiplied by its position, and divide by 103. The remainder is the check character. Here is BIN-07, which starts in set B (value 104).

Position	Character	Set B value	Position × value
Start	Start B	104	104
1	`B`	34	34
2	`I`	41	82
3	`N`	46	138
4	`-`	13	52
5	`0`	16	80
6	`7`	23	138
Sum, then sum mod 103			628 → 10

Choosing

Code 128 vs Code 39 vs QR: Same Value, Different Size

Each row is the tool's own output. Linear widths are at X = 0.33 mm; QR is at a 0.5 mm module and is square.

Value	Symbology	Encoded as	Modules wide	X (mm)	Width
`A12-R04-B01`	Code 128	Set B	176	0.33	58.1 mm
`A12-R04-B01`	Code 39	13 characters with start/stop	207.5	0.33	68.5 mm
`A12-R04-B01`	Code 39 + mod 43 check	14 characters with start/stop	222	0.33	73.3 mm
`A12-R04-B01`	QR Code	Version 1, 21 × 21 modules	29	0.50	14.5 mm square
`100045678912`	Code 128	Set C	121	0.33	39.9 mm
`100045678912`	Code 39	14 characters with start/stop	222	0.33	73.3 mm
`100045678912`	Interleaved 2 of 5	6 digit pairs	124.5	0.33	41.1 mm
`100045678912`	QR Code	Version 1, 21 × 21 modules	29	0.50	14.5 mm square

Default

Code 128

Internal SKUs, bins, totes, carton IDs. Narrowest linear option for mixed text.

Legacy

Code 39

1.2× the width of Code 128 for A12-R04-B01. Choose it when a scanner or system requires it.

Phones

QR Code

URLs and longer text that a phone camera reads. Needs a 2D imager, not a laser scanner.

Retail

UPC / EAN

Products sold at a till. The number comes from a GS1 company prefix, not from this tool.

Worked example

24 Bin Labels for a Warehouse in Reno, Nevada

A team re-slotting aisle 12 needs Code 128 labels for bins A12-R04-B01 to B24, printed on 2 × 1 in labels from a thermal printer.

PrefixA12-R04-B

Start · count · pad1 · 24 · 2 digits

SymbologyCode 128, auto

Label width2 in (50.8 mm)

58.1 mmwidth at X = 0.33 mm. Too wide for 2 in.

0.28 mmlargest X that fits, rounded down

49.3 mmwidth at 0.28 mm (1.94 in)

0.24 mmlargest X in Code 39 for the same label

Bin	Check character	Width at 0.28 mm
`A12-R04-B01`	78	49.3 mm
`A12-R04-B02`	89	49.3 mm
`A12-R04-B03`	100	49.3 mm
`A12-R04-B22`	6	49.3 mm
`A12-R04-B23`	17	49.3 mm
`A12-R04-B24`	28	49.3 mm

Every bin value has the same length and set path, so all 24 barcodes share one width. Only the check character changes.
Code 39 would force the bar down to 0.24 mm on the same label, against 0.28 mm for Code 128.
Load bin-label example in the tool reproduces this run. Print one, scan it at rack height, then print the rest.

Print size

Barcode Size: How the X Dimension Sets the Width

Every bar and space is a whole multiple of X, so the width scales in a straight line with it. Height does not change what is encoded.

X or module size	SKU-88421, Code 128	golocad.com/tools/ as QR (version 2, M)
0.25 mm	35.8 mm · 1.41 in	8.3 mm square · 0.32 in
0.33 mm	47.2 mm · 1.86 in	10.9 mm square · 0.43 in
0.50 mm	71.5 mm · 2.81 in	16.5 mm square · 0.65 in
0.75 mm	107.3 mm · 4.22 in	24.8 mm square · 0.97 in
1.00 mm	143.0 mm · 5.63 in	33.0 mm square · 1.30 in

Scanner range

Narrow bars read only up close. Check your scanner's specification for the smallest X it resolves at your reading distance.

Printer resolution

A 203 dpi thermal head prints dots 0.125 mm wide. Bars that are not whole dots get rounded unevenly.

Retail symbols

UPC and EAN have a nominal size and a permitted magnification range set by GS1. Follow it for products sold at a till.

Word, Excel and fonts

Putting a Barcode in Word or Excel

Two of the most asked questions are how to make a Code 128 barcode in Word and where to get the font. An image file is the reliable route.

Why a font alone fails

Code 128 needs a start code, a calculated check character and a stop code. Typing the value in a barcode font leaves them out, so scanners reject it.

Insert the image

Download SVG or PNG here, then Insert, Pictures. Lock the aspect ratio. If your version of Word will not take SVG, use the PNG.

Many labels at once

Paste the spreadsheet column into Bulk list and print the sheet, rather than building a mail merge around a font.

Check digits

UPC, EAN and ITF-14 Check Digits

Retail and carton numbers end in a GS1 mod 10 check digit. Type the number without it and the tool appends it; type all of it and the tool verifies it.

sum = digits × 3, 1, 3, 1 … from the right check = (10 − sum mod 10) mod 10

For UPC-A 61414100001: sum = 48, so the check digit is 2 and the full number is 614141000012.

Symbol	Number without check	Weighted sum	Check digit
UPC-A	`61414100001`	48	2
EAN-13	`590123412345`	83	7
EAN-8	`9638507`	86	4
ITF-14	`1061414100041`	55	5

Building GS1-128, SSCC or pallet labels? Those need Application Identifiers and FNC1 characters that plain Code 128 does not add. Use the GS1 barcode generator instead.

Avoid reprints

Six Barcode Mistakes That Fail at the Scanner

Stretching the image

Resizing in one direction changes the ratio between bars. Change X in the tool and download again instead.

Cutting the quiet zone

The blank margin is part of the symbol. Every width on this page includes it, so plan the label around the full width.

Forcing set B on numbers

100045678912 is 61.7 mm in set B against 39.9 mm in auto. Leave the set on Auto unless a system needs one set.

Lower case in Code 39

Code 39 has no lower case. The tool converts to upper case and says so, but your database still holds the original.

Odd digit counts in ITF

Interleaved 2 of 5 encodes pairs. An odd-length number needs a leading zero, which then becomes part of the scanned value.

Inventing a UPC

A made-up retail number can match another brand's product. Use the GS1 prefix issued to your business.

Next step

Related Labelling and Warehouse Tools

GS1 barcode generatorGS1-128 with SSCC, batch and expiry, plus UPC, EAN and ITF-14 for GS1 numbers.SKU generatorBuild consistent SKU codes before you turn them into barcodes.Shipping label generatorLay out a shipping label with addresses and package details.Pallet calculatorWork out cartons per pallet before you label the cases.

See all free logistics tools, or read how Locad runs warehousing and ecommerce fulfillment.

FAQ

Barcode Generator Questions

Pick a symbology, type the value and the barcode draws as you type. SKU-88421 in Code 128 comes out 47.2 mm wide at a 0.33 mm bar. Download it as SVG or PNG, or open a print sheet. Use Code 128 for your own SKUs and bins, and a GS1-issued number for retail UPC or EAN.

There is no 128-bit barcode. The name you want is Code 128, a linear symbology that can encode all 128 ASCII characters. Choose Code 128 above and type your value. The tool picks set A, B or C, adds the modulo 103 check character, and adds start and stop codes.

Generate the barcode here, download it as SVG or PNG, then use Insert, Pictures in Word. Keep the aspect ratio when you resize it. Typing a value in a Code 128 font is not enough on its own, because the start code, check character and stop code must be calculated first.

You do not need a font to get a scannable Code 128 barcode. A font only draws bars for characters you give it, so something still has to calculate the check character and add start and stop codes. This tool does that and gives you an image file instead.

Switch to Bulk list and paste one value per line, straight from a spreadsheet column. Add a caption after a vertical bar. For numbered runs such as bins, use the sequence builder: prefix, start number, count and zero padding. Up to 250 barcodes render at once.

Code 128 covers upper and lower case and packs digits in pairs, so it is narrower. A12-R04-B01 is 68.5 mm wide in Code 39 against 58.1 mm in Code 128 at the same bar width. Code 39 survives where older scanners or systems require it.

No. GS1-128, once called EAN-128, is Code 128 with an FNC1 character after the start code and data written as GS1 Application Identifiers, such as SSCC or batch. Use our GS1 barcode generator for those labels. Plain Code 128 suits internal SKUs, bins and carton IDs.

Only with a number that is legitimately yours. Retail UPC and EAN numbers come from a GS1 company prefix issued to your business. This tool draws the symbol and checks the check digit. It does not issue numbers, and an invented UPC can clash with another product.

Size is set by the narrowest bar, the X dimension. Every bar scales with it. SKU-88421 in Code 128 is 35.8 mm wide at 0.25 mm and 71.5 mm at 0.5 mm, quiet zones included. Choose your label width in the tool and it shows the largest X that fits.

The usual causes are bars printed too narrow for the scanner, quiet zones cut off by the label edge, low contrast, and stretching the image in one direction. Download at true size, keep the margins, print dark bars on a light background, and test with the scanners on your floor.

Want the Scanning Done for You?

Talk to Locad about receiving, storage and fulfillment for your inventory.

Talk to Locad