Reference caliper values for common packaging stocks, and a converter between mil, mm, inches, PostScript points and microns. Use it to cross-check specs on a supplier data sheet or a print file.

Folding carton and paperboard stocks

Typical industry medians. Actual caliper varies by mill, furnish and calendering: verify with your supplier’s data sheet for structural or fit-critical applications.

Stock	Basis weight	Caliper (mil)	Caliper (mm)	Typical use
SBS (solid bleached sulfate)	60 lb / 16 pt	16	0.41	Cosmetics, pharma, food cartons
SBS	80 lb / 18 pt	18	0.46	Retail folding cartons, premium packaging
SBS	90 lb / 20 pt	20	0.51	Candles, health supplements
SBS	100 lb / 24 pt	24	0.61	Heavier cartons, luxury retail
CRB (coated recycled board)	70 lb / 18 pt	18	0.46	Mid-range cartons, food service
CRB	80 lb / 22 pt	22	0.56	Retail cartons, eco-positioned brands
CNK (coated natural kraft)	60 lb / 18 pt	18	0.46	Kraft-look cartons, natural brands

Chipboard and grayboard

Board grade	Thickness (mm)	Thickness (mil)	Typical use
Grayboard 700 gsm	1.0	39	Rigid boxes, thin-lid construction
Grayboard 1,000 gsm	1.5	59	Standard rigid box walls
Grayboard 1,350 gsm	2.0	79	Premium rigid boxes, heavier lids
Grayboard 1,700 gsm	2.5	98	Extra-heavy rigid boxes, keepsake packaging
Chipboard (standard)	1.0–1.6	39–63	Inserts, partitions, backing cards

Corrugated liner and fluting

Component	Basis weight (lb/MSF)	Caliper (mil)	Caliper (mm)
Kraft liner (35 lb)	35	9–10	0.23–0.25
Kraft liner (42 lb)	42	11–12	0.28–0.30
Kraft liner (69 lb)	69	17–18	0.43–0.46
E-flute (assembled, single wall)	—	59–71	1.5–1.8
B-flute (assembled, single wall)	—	97–118	2.4–3.0
C-flute (assembled, single wall)	—	142–157	3.6–4.0
BC double wall	—	236–276	6.0–7.0

Label and film stocks

Material	Caliper (mil)	Caliper (µm)	Typical use
BOPP clear	2.0	51	Product labels, clear labels
White BOPP	3.0	76	Opaque product labels
PETG film	2.0–3.5	51–89	Shrink sleeve labels
Thermal transfer paper	3.3–4.0	84–102	Shipping labels, barcode labels
Chrome coat label paper	4.0–5.5	102–140	High-gloss pressure-sensitive labels

Unit reference

Unit	Abbrev.	Definition	Common in
Mil (thou)	mil	1/1,000 of an inch (0.001″)	US board specs: “16 pt board” = 16 mil
Millimeter	mm	1/1,000 of a meter (0.0394″)	Metric specs, grayboard, EU suppliers
Inch	in	25.4 mm exactly	Dieline templates, US print specs
PostScript point	pt	1/72 of an inch (0.3528 mm)	Illustrator, InDesign, PDF files, not the same as board “pt”
Micron	µm	1/1,000,000 of a meter (0.001 mm)	Film thickness, label stocks

Why board “pt” and PostScript “pt” are different numbers

In the US board trade, “pt” means thousandths of an inch: the same as mil. A 16 pt board is 0.016″ thick. In Adobe Illustrator or InDesign, “pt” means PostScript points (1/72″ = 0.01389″). This converter uses the PostScript definition. When a US supplier writes “16 pt,” they mean 16 mil (0.016″), not 16 PostScript points (0.222″).

How caliper affects packaging design

Board caliper adds directly to finished box size. A folding carton with 16 mil walls is 0.032″ narrower inside than its dieline blank width (two walls). For tight-tolerance inserts or nested boxes, build caliper into every panel calculation. Thicker board also requires deeper scores, and affects print registration on offset presses. For the relationship between caliper and stacking strength in corrugated, see the box compression calculator.

Cite this reference

Tria Packaging. Paper and board thickness chart: caliper, mil, mm, pt converter. Retrieved from triapackaging.com/tools/paper-thickness-chart/. Caliper ranges compiled from TAPPI standard test conditions and North American board supplier specifications.

Paper and board thickness chart