What is Paper Weight Converter?
Paper suppliers describe stock in different ways depending on the region and product: GSM (grams per square meter) is the metric standard used almost everywhere outside North America, while the US paper industry still quotes basis weight in pounds and card thickness in points or thousandths of an inch (caliper). This converter switches between them.
Enter a value in any of the four units — GSM, lb, pt, or caliper — and see the equivalent in the other three instantly, using this tool's fixed relative scale (GSM as the baseline).
The paper weight converter supports 4 units — GSM, lb, pts, and caliper. Enter a value, pick the source and target units, and the result updates instantly alongside a chart comparing it across every unit.
When to Use This Calculator
- Sourcing paper or cardstock from a supplier that quotes weight in a different unit than you're used to.
- Reviewing a print or packaging spec sheet that mixes GSM, lb, and caliper values.
- Designing packaging where board thickness (caliper) needs to match existing tooling.
- Comparing paper options for a print run when quotes come from both US and international vendors.
- Teaching or learning the units used in the printing and packaging industry.
- Quickly estimating an equivalent unit before confirming exact figures with a paper mill or supplier.
Steps:
- Enter the paper weight or thickness value you want to convert in the input field.
- Select the source unit from the dropdown (e.g., GSM).
- Select the target unit from the second dropdown (e.g., lb).
- The converted result appears instantly with full precision.
- Use the swap button to reverse the conversion direction.
- Click "Copy" to copy the result to clipboard.
- View the bar chart below to compare the value across every supported unit.
Formula
Values convert through a fixed relative scale using GSM as the base (1 GSM = 1 base unit): 1 lb ≈ 1.6275 base units, 1 point (pt) ≈ 0.352 base units, and 1 caliper unit (thousandths of an inch) ≈ 352 base units. To convert between any two units, multiply by the source unit's base factor, then divide by the target unit's base factor — for example, 20 lb × 1.6275 ÷ 1 ≈ 32.55 GSM.
Use Cases
- Comparing a US supplier's "lb" paper weight against a GSM specification from an international print shop.
- Checking whether a cardstock's caliper thickness will fit existing packaging or die-cut equipment.
- Converting a printing spec sheet's units to match what your local supplier quotes.
- Estimating the GSM equivalent of a familiar US paper weight when ordering from abroad.
Key Benefits
- Instant conversion between 4 paper measurement units: GSM, lb, pts, and caliper.
- Useful when comparing paper stock specs from US and international suppliers side by side.
- Bar chart compares the entered value across every supported unit at a glance.
- No manual lookup tables needed when reviewing print or packaging specifications.
- Full-precision toggle for print production work that needs exact figures.
- Free, no registration required, works offline after the first load.
Pro Tips
- When comparing quotes from suppliers using different units, convert everything to GSM first, since it's the most universal reference.
- Remember that "lb" paper weight in the US industry depends on the paper category (bond, text, cover) — for critical print jobs, confirm the exact category with your supplier rather than relying on a single conversion factor.
- Points and caliper describe thickness, not weight — don't assume a higher point value always means heavier paper.
- Use the bar chart to sanity-check a converted value against the other three units at once.
- For packaging and cardstock, caliper (thousandths of an inch) is often the spec that determines whether the material fits existing die-cut tooling.
- Keep a note of your most-used paper stock's GSM value for quick reference across projects.
Common Mistakes to Avoid
- Assuming "lb" paper weight means the same thing across bond, text, and cover categories — the reference sheet size differs, so the same lb number can represent different actual weights.
- Confusing weight (GSM, lb) with thickness (points, caliper) — a heavier paper is not automatically thicker.
- Using a single fixed conversion factor for critical print production without confirming the exact figures with your paper supplier.
- Forgetting that GSM is an area-based measurement (per square meter), so it doesn't change if you cut the sheet smaller.
- Mixing up points (paper thickness) with font points (a typography unit) — they share a name but measure different things.
- Assuming international and US paper sizes (A4 vs Letter) don't affect how basis weight is reported — they do, since basis weight is defined relative to a reference sheet size.
Key Terms Explained
- GSM (Grams per Square Meter) — The metric standard for paper weight, used almost everywhere outside North America.
- Basis Weight (lb) — The US paper industry's traditional weight measurement, tied to a reference sheet size that varies by paper category.
- Point (pt) — A thickness unit for paper and card stock, common in the printing industry for items like business cards.
- Caliper — Paper or board thickness measured in thousandths of an inch, important for packaging and die-cutting.
- Bond, Text, and Cover Paper — US paper categories, each with a different reference sheet size, which is why "lb" values aren't directly comparable across categories.
- Stock — A general term for the specific type and weight of paper or card used for a print job.
- Opacity — How much printing shows through from the other side of the sheet, related to but distinct from weight and thickness.
- Coated vs Uncoated Paper — A finish distinction that affects print quality independently of paper weight or thickness.
Related Concepts
- Basis Weight — The paper industry term for weight-per-reference-sheet-area, the basis for the US "lb" system.
- GSM (Grams per Square Meter) — The area-based metric standard used internationally.
- Paper Caliper — Thickness measurement critical for packaging, die-cutting, and folding specifications.
- Print Substrate — The general term for the material (paper, card, film) printed on.
- Cardstock vs Text Weight — Common categories describing how paper is used (covers vs body pages) and their typical weight ranges.
- Paper Grain Direction — How paper fibers align, affecting fold quality and strength independently of weight or thickness.
Example
Example: Convert 100 GSM to pounds. Result: 100 GSM ≈ 61.44 lb.
