A barcode is a machine-readable version of a value. Choosing the right value comes before generating the image. Learn when to enter an assigned identifier and when to generate an internal or test code.
Do I just enter any number?
For retail products, use the identifier properly assigned to that product. For your own internal tracking, you can assign a unique code that your system understands. Random values are for testing the design and scanner only.
01 / THE VALUE AND THE IMAGE
The bars carry a code. Your system gives it meaning.
The value is the text or number encoded in the barcode. The format (such as EAN-13 or Code 128) is the set of rules used to turn that value into bars and spaces. A scanner reads those bars and returns the value.
Assigned value→Barcode image→Scanner reads value→Your product record
For retail products, a GTIN (Global Trade Item Number) identifies a particular product and pack configuration. EAN-13, EAN-8 and UPC-A carry GTINs. The number does not automatically contain the product name, price, ingredients or expiry date. A shop’s till or inventory software needs a product record linking that number to the product and price.
If your GTIN-13 is allocated from a GS1 Company Prefix, it combines that prefix, an item reference for your product, and a final check digit. Prefix lengths vary, so follow your GS1 allocation instructions rather than splitting the number into fixed blocks. Do not build the number by joining your phone number, product size or price.
Amoliza Barcode Studio creates and checks barcode images. It does not issue GS1 identifiers, register products, check ownership or add products to a retailer’s catalogue.
Ask your retailer or marketplace which identifier and barcode format it accepts.
If you own the brand, contact GS1 through its local member organisation to obtain an appropriate GTIN allocation or company prefix. Follow its assignment process for each product.
Keep a record of which GTIN belongs to each product, size, flavour and pack. If the product already has an assigned GTIN, get the exact number from the brand owner or your authorised product records.
Enter that value here and generate the label. Give your retailer the product information needed to list it.
If the barcode is only for a system you control, choose Code 128 and use your existing SKU or another unique internal identifier, for example AMO-TAM-350.
Record that code against the correct item in your stock system. Avoid assigning the same code to different items. Check that your scanner and software accept the chosen format and characters.
This internal code does not become a registered retail GTIN. Code 39 is another option if your system requires it.
TRYING THE EDITOR OR A PRINT SAMPLE
Use a clearly marked test value.
The studio’s Generate test value button creates a value the selected format can encode. For EAN/UPC it includes a calculated check digit.
You can also enter a product name and choose Generate as → EAN-13 · date-based test value. Manufacturing date, expiry date and time determine a repeatable sample number. It does not encode readable dates or establish a retail product identifier. Keep the assigned retail GTIN unchanged across batches.
It does not reserve the number, check whether another business uses it or assign it to your product. Keep test codes off production retail labels.
03 / AUTOMATIC VALUE GENERATION
Generate from a product name, with optional dates.
The Generate as selector offers two different workflows. Choose the one that matches your purpose; choosing EAN-13 does not turn a generated number into an assigned retail GTIN.
INTERNAL PRODUCT TRACKING
Code 128: a readable code from the name.
Enter Product name, leave Generate as → Code 128 · internal product code selected, and keep Auto-generate internal code enabled. For example, Amoliza Tamarind Drink 350 ml becomes AMOLIZA-TAMARIND-DRINK-350-ML.
The studio converts the name to uppercase, normalizes accents and replaces separators with hyphens. Check your records for duplicate codes: different names can normalize to the same value. Longer names may need a wider printed barcode; follow the narrow-bar warning and test a physical label.
EAN-13 PRINT AND SCANNER TESTING
EAN-13: a number from name, dates and time.
Enter Product name, for example Amoliza Tamarind Drink 350 ml.
Choose Generate as → EAN-13 · date-based test value. The barcode format changes to EAN-13.
Set Manufacturing date and Expiry date. Expiry must be on or after manufacture. Enter the actual intended dates; the studio does not calculate a shelf life.
Set Manufacturing time (Accra / UTC), including seconds when needed. Use current date & time fills the manufacturing date and time once. It does not change the expiry date or run a ticking clock.
Keep Auto-generate EAN-13 test value enabled. Once the fields are valid, the 13-digit value and preview update automatically. Review the test-only notice before downloading.
WHAT THE GENERATED NUMBER MEANS
Repeatable does not mean registered or unique.
The normalized name, both dates and time are mixed into 12 digits, and the studio calculates a final check digit. The same inputs reproduce the same value. Changing an input generally changes the value, but different inputs can produce the same number.
The number does not store readable manufacturing or expiry dates. A scanner returns the 13 digits; it cannot recover the name, dates or time. Keep that information in your own product or batch records.
These are unregistered test numbers. The studio does not reserve them or check whether they are already in use. Do not replace an assigned retail GTIN with a date-based value, or change the retail GTIN for every production batch.
EAN-13 EXAMPLE · TEST ONLY · NOT ASSIGNED TO AMOLIZA
Product: Amoliza Tamarind Drink 350 ml Manufactured: 2026-11-08 Expires: 2027-11-08 Time: 14:30:05, Accra / UTC
9901221315816
The underlined final digit is the check digit. The dates above are demonstration inputs, not a recommended shelf life or a claim about the reference product.
Manual edits and validation.
Editing Barcode value or Barcode format, or using Generate test value, pauses automatic generation. That test button creates a random sample for the selected format; it does not use your date fields. Re-enable the appropriate auto-generate checkbox to use the current name and dates again. Changing Generate as also re-enables automatic generation.
Missing or invalid dates, an expiry before manufacture, invalid time, or an unusable product name stop generation and disable barcode export. New project clears the product name and expiry date and returns generation to Code 128. Product names, dates and generated values remain in browser session memory and are lost on reload.
For a real retail label, get the GTIN assigned to that exact product, select the required Barcode format and type the assigned number into Barcode value. Manual entry pauses automatic generation so date changes will not overwrite that value.
04 / WHAT YOU CAN ENTER
Match the format to the identifier you have.
Format
Accepted in this studio
Where the value comes from
EAN-13
13 digits, or 12 for the studio to calculate the last digit.
An assigned GTIN-13 for retail. The date-based generator produces unregistered test values only; see the automatic generation section.
EAN-8
8 digits, or 7 to calculate the last digit.
An assigned GTIN-8. Do not shorten an EAN-13 to make one.
UPC-A
12 digits, or 11 to calculate the last digit.
A GTIN-12 assigned to the product; confirm your retailer’s requirements.
Code 128
Printable ASCII text, such as AMO-TAM-350. Up to 80 characters in this studio.
An internal SKU, asset ID or other code agreed with your receiving system.
Code 39
Uppercase A–Z, digits, spaces and - . $ / + %. Up to 80 characters. Do not enter start/stop asterisks.
An internal code when your scanner/software requires Code 39.
Keep leading zeros and enter EAN/UPC values without spaces or hyphens. Do not invent a GS1 company prefix or use a country prefix as a substitute for obtaining an allocation.
This studio’s Code 128 option is ordinary Code 128. It does not implement GS1-128 Application Identifiers for structured batch, expiry or shipping data. Confirm those requirements with your trading partner before choosing a format.
For Amoliza Tamarind Drink 350 ml, first find out whether that exact product already has an assigned GTIN. Get it from your GS1 records or the brand owner’s product master. If you are only replacing the barcode artwork, keep the correct existing value.
Multiple bottles of the same 350 ml product normally share the same product GTIN. It is not a unique serial number for every bottle.
A 500 ml version, another flavour or a different pack configuration generally needs its own GTIN under GS1 allocation rules.
Batch number, manufacturing date and expiry date are separate information. Do not change the retail GTIN each time a new batch is made.
The bundled reference artwork and the studio’s starting number are examples. Loading the artwork does not extract or verify its barcode, and does not assign the starting number to Amoliza.
The last digit of an EAN/UPC value is calculated from the preceding digits. It helps detect input or reading errors. The studio can add this digit when you enter one digit fewer than the full length, or verify it when you enter the complete number.
EXAMPLE ONLY · NOT ASSIGNED TO YOUR PRODUCT590123412345 → 5901234123457
The final 7 is the calculated check digit. Use your assigned product number instead of this example.
“Valid EAN-13 value” means the length, digits and check digit pass validation. It does not mean the number is registered, unique, owned by you, approved by a retailer or suitable for your product. This studio does not perform a GS1 registry lookup.
For Code 128, the encoding library handles the symbol checksum. Do not append an EAN/UPC check digit to an internal alphanumeric code.