GSM stands for grams per square meter. It is the ISO standard for measuring paper weight and is the most straightforward system: one square meter of the paper is weighed in grams. Higher GSM means heavier, thicker paper.

Why are there so many lb systems (Bond, Cover, Text, Index)?

US paper weights are based on the weight of 500 sheets (a ream) at a "basic size" that differs by paper grade. Bond paper uses a 17×22 in basic size, Text uses 25×38 in, Cover uses 20×26 in, and Index uses 25.5×30.5 in. Because the basic sizes differ, the same physical paper gets a different lb number in each system.

How accurate are the conversions?

The tool uses the standard industry multiplication factors published by paper manufacturers. Small rounding differences of ±1–2 units are normal and reflect the fact that real paper batches have slight tolerances from the nominal GSM.

What is "ream weight"?

A ream is traditionally 500 sheets. Ream weight is the total mass of 500 sheets cut to the sheet size you selected. It is useful for estimating shipping costs and storage load.

Which weight system should I use for business cards?

Business cards typically use Cover stock. A 14 pt card is roughly 260 GSM (about 100 lb Cover). For a premium feel, 16–18 pt (280–350 GSM / 110–130 lb Cover) is common.

Is 20 lb Bond the same as 75 GSM?

Yes, 20 lb Bond converts to approximately 75 GSM. Standard office copy paper is 20 lb Bond (75 GSM) or 24 lb Bond (90 GSM).

Paper Weight Calculator

Name: Paper Weight Calculator
Availability: InStock
Author: Nham Vu

Enter a paper weight in any system (GSM, lb Bond, lb Cover, lb Text, lb Index) and instantly see all equivalent weights plus ream and sheet weight estimates.

Paper Weight Input

Weight System

Weight Value (GSM)

Sheet Size (for ream & sheet weight)

Common Paper Weights

Use	GSM	lb Bond	lb Cover
Copy paper	75	20	28
Premium letter	90	24	33
Brochure text	130	—	50
Business card	260	—	100
Heavy card	350	—	130

Enter a weight value and click Convert

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Summary

Enter a paper weight in any system (GSM, lb Bond, lb Cover, lb Text, lb Index) and instantly see all equivalent weights plus ream and sheet weight estimates.

How it works

Select the weight system you already know (e.g., GSM or lb Bond).
Enter the numeric weight value in the input field.
Optionally, choose a sheet size (Letter, A4, Legal, Tabloid, etc.) to get per-sheet weight.
The tool instantly converts to all other weight systems.
Ream weight (500 sheets) and single-sheet weight are shown for the chosen size.

Use cases

Compare paper from international suppliers who quote GSM vs. US lb grades.
Estimate shipping weight for a print job before ordering.
Verify that a paper stock labeled in lb Bond matches a GSM spec from a spec sheet.
Choose the right paper weight for business cards, letterheads, or brochures.
Calculate how much a ream of cover stock will weigh for freight planning.
Cross-check printer paper specifications between European and North American vendors.
Educate designers on the difference between Text weight and Cover weight.
Determine the per-sheet weight when costing custom stationery.

Frequently Asked Questions

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Last updated: 2026-05-23 · Reviewed by Nham Vu