Enter Paper Details
Formula Used
When GSM is known:
Thickness in microns = GSM × bulk × adjustment factor
When basis pounds are known:
GSM = pounds × 453.59237 ÷ basis area in square meters
Density conversions:
Bulk = 1000 ÷ density in kg/m³
Bulk = 1 ÷ density in g/cm³
Stack height:
Stack height = single sheet thickness × number of sheets
How to Use This Calculator
- Enter paper weight as GSM or select pounds by basis size.
- Choose the correct basis type when using pound weight.
- Use custom width, height, and sheet count for special stocks.
- Select bulk mode when the supplier gives bulk.
- Select density mode when the supplier gives density.
- Add a positive or negative adjustment for finish changes.
- Enter sheet count to estimate total stack height.
- Press calculate, then export the result if needed.
Example Data Table
| Paper Type | Weight | Bulk | Estimated Thickness | Common Use |
|---|---|---|---|---|
| Copy Paper | 80 GSM | 1.20 | 96 microns | Office printing |
| Text Stock | 100 GSM | 1.25 | 125 microns | Brochures |
| Cover Stock | 250 GSM | 0.90 | 225 microns | Cards and covers |
| Bulky Book Paper | 70 GSM | 1.80 | 126 microns | Books |
Paper Thickness Matters
Paper weight alone does not tell the full story. Two sheets can share the same GSM and still feel different. The missing value is bulk. Bulk describes how much volume one gram of paper occupies. A fluffy uncoated sheet has high bulk. A dense coated sheet has low bulk. This calculator combines weight and bulk to estimate caliper. Always request a sample when the project needs strict folding, binding, mailing, or luxury presentation tolerances.
Weight, Bulk, and Caliper
GSM means grams per square meter. It measures mass over area. Caliper is the measured sheet thickness. It is commonly shown in microns, millimeters, mils, or points. A common rule is simple. Thickness in microns equals GSM multiplied by bulk. For example, 100 GSM paper with 1.2 bulk is about 120 microns.
Basis Weight Support
Many print quotes still use pounds. The pound value depends on the basis size. Text, bond, cover, index, and bristol stocks use different parent sheet sizes. This page converts the selected pound basis to GSM first. Then it estimates thickness from the chosen bulk or density. Custom basis dimensions help when a mill uses another parent size.
Better Planning
Use the stack height result when planning binders, mailers, cartons, catalogs, menus, or packaging inserts. Enter the number of sheets in the job. The tool multiplies single sheet caliper by that count. This gives a quick height estimate before ordering material. Add a small allowance for air, folds, glue, coatings, and production variation.
Practical Accuracy
The result is an estimate, not a certified mill reading. Real paper thickness changes with moisture, coating, fiber mix, pressure, and measurement method. Use the density mode when a supplier gives density. Use bulk mode when a datasheet lists bulk directly. For final specifications, compare this estimate with a caliper gauge or the supplier sheet.
Common Print Uses
Designers use thickness to judge feel and stiffness. Printers use it to check folding limits and machine clearance. Mail teams use it to estimate envelope fit and postage class. Packaging teams use it to predict insert height. Buyers use it to compare stocks that have similar weight but different hand feel.
FAQs
What is paper thickness?
Paper thickness is the caliper of one sheet. It is usually measured in microns, millimeters, mils, or points. It affects stiffness, folding, mailing thickness, and product feel.
Can GSM directly convert to thickness?
GSM needs bulk or density for a useful thickness estimate. The same GSM can produce different calipers because paper structure, coating, and compression can change sheet thickness.
What is paper bulk?
Bulk is volume per gram of paper. It is often shown as cm³/g. Higher bulk means a thicker sheet for the same GSM. Lower bulk means a denser sheet.
Are mils and points the same here?
For paper caliper, one mil equals 0.001 inch. Many print buyers also call this one point. This calculator treats caliper points and mils as equal.
Why does basis weight need a paper type?
Pound basis weight depends on parent sheet size. Bond, text, cover, index, and bristol use different basis dimensions. The calculator converts each type to GSM first.
How accurate is the result?
The result is an estimate for planning. Actual paper thickness can change with moisture, coating, pressure, fiber mix, and mill tolerance. Use supplier data for final buying decisions.
When should I use density mode?
Use density mode when a datasheet gives paper density instead of bulk. The calculator converts density into bulk, then estimates sheet thickness from the converted GSM.
Can I calculate stack height?
Yes. Enter the number of sheets in the stack field. The calculator multiplies single sheet thickness by that count and shows the stack height in millimeters and inches.