Core ID / OD / wall thickness chart
The spec-anchor chart for paper cores: common inside diameters, wall thicknesses, and resulting outside diameters, plus how to measure each one correctly.
Three numbers define a core: ID (inside diameter — what your chuck or shaft sees), wall (the paper thickness), and OD (outside diameter — ID plus twice the wall). Measure ID with a caliper across the opening at two angles; measure wall on a cut edge; never trust OD alone, because two very different cores can share it.
| ID | Common walls | Resulting OD | Typical use |
|---|---|---|---|
| 1″ | .060″–.083″ | 1.12″–1.17″ | Tape, ribbon, small rolls |
| 1.5″ | .060″–.090″ | 1.62″–1.68″ | Label stock, films |
| 2″ | .060″–.100″ | 2.12″–2.20″ | Mailing tubes, light rolls |
| 3″ | .080″–.125″ | 3.16″–3.25″ | Converter standard, mill rolls |
| 4″ | .090″–.125″ | 4.18″–4.25″ | Heavy rolls, shipping |
| 6″ | .100″–.125″+ | 6.20″–6.25″+ | Wide-web, high-speed unwinds |
| 8″ | .115″–.125″+ | 8.23″–8.25″+ | Jumbo and specialty |
NHPT winds every ID from 1″ to 8″ with walls from .030″ to .125″ and beyond, cut 1″ to 120″. If your size is not on the chart, that is what custom mandrels are for.
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FAQ
How do I measure core ID correctly?
Caliper across the inside opening at two perpendicular angles and average — a single measurement can hide out-of-round.
How is OD calculated?
OD = ID + (2 × wall). A 3" ID core with a .100" wall has a 3.200" OD.
What wall thickness do I need?
It depends on roll weight, tension, and handling — see our crush strength guide, or send specs for a same-day recommendation.