There is no single font size that is automatically safe for every label. A clean sans-serif with open letterforms can remain readable at a size where a thin decorative font becomes difficult. Material, contrast, printing and viewing distance also influence the result.
Instead of chasing the smallest possible number, design around legibility and any applicable regulatory requirements for your product category. Then prove the decision with an actual-size printout.
Font design matters as much as point size
Two fonts set at the same nominal size can have very different x-heights, stroke weights and internal spacing. Thin strokes and compressed letters lose clarity sooner than open, sturdy forms.
Use decorative typography for larger brand elements and reserve simpler faces for dense supporting information.
Contrast is part of readability
Small white text over a complex photograph or transparent bottle may be harder to read than slightly smaller black text on a clean white field. The background should support the text instead of competing with it.
On clear labels, white underprint can stabilize a reading area. On metallic stock, avoid relying on subtle tonal differences for critical information.
Line spacing and width affect comfort
Tiny text becomes especially tiring when lines are long or tightly packed. Narrow columns, sensible leading and clear paragraph breaks can improve usability without increasing the label size.
Do not fill every gap simply because the space exists. Empty space can make the information easier to navigate.
Print the label at 100 percent
A design viewed at 300 percent zoom gives a false sense of comfort. Print the label at final size, place it on the container and read it under ordinary lighting.
Check the file against the Artwork Guide and leave enough safe area around small text so it is not visually crowded by the cut.
Turn the guide into a real specification.
Choose your material, size, shape, finish and quantity, then see the price before checkout.