Paper weight converter

What the paper weight converter returns and which stocks it understands

A paper weight conversion answers a narrow question: given a magnitude in gsm or US basis pounds for a named stock family, what is the equivalent magnitude in the other unit. This calculator accepts a numeric value, a source unit, a target unit, and a stock, then returns the converted result rounded to a stable precision, the canonical from and to identifiers, human-readable unit and stock labels, the intermediate value in grams per square meter, the lb-to-gsm factor for that basis size, the basis sheet dimensions in inches, the basis area in square inches, and a short formula reminder. Canonical stocks are text for book and offset, bond for writing papers, cover for cover stocks, and index for index and bristol boards. Everyday aliases such as writing, book, offset, bristol, and cover_stock normalize to those ids so forms, query strings, and spreadsheets can reuse the same contract without inventing private enums. Units are gsm for grams per square meter and lb for US basis pounds, with aliases like g/m2, grams_per_square_meter, pounds, and basis_lb. There is no approximate feel-of-paper path and no brand-specific caliper table: the engine either multiplies and divides by fixed basis-size factors inside the supported magnitude range or rejects the input with invalid_input. Rejected cases include missing value, from, to, or stock; non-finite numbers; magnitudes above the documented ceiling; unknown unit strings; and any stock string that is not on the supported list.

How basis sizes define the factor and how results stay reproducible

Optional scientific notation on the value string is allowed when it parses as a finite decimal; embedded spaces, hex prefixes, and non-numeric tokens are rejected with a clear message so a bad cell does not become a wrong ream weight. Zero is a valid value and simply yields zero in the target unit. The lb-to-gsm factor equals four hundred fifty-three point five nine two three seven grams per pound times square inches per square meter, divided by five hundred sheets times the basis area in square inches. Converting from pounds multiplies by that factor; converting from gsm divides by it; same-unit requests echo the value after validating stock. The preferred fields are value for the weight magnitude, from for the source unit, to for the target unit, and stock for the paper family, with aliases amount, weight, n, and quantity for the value, unit, from_unit, source, and input_unit for from, target, to_unit, output_unit, and into for to, and type, grade, basis, paper_type, and stock_type for stock so heterogeneous clients can share one contract. An optional precision field, with aliases decimals and dp, chooses how many decimal places to expose for numeric fields, defaulting to ten and capped at fifteen so JSON goldens stay stable. Computation bridges through gsm using the industry basis sheet for each stock: bond uses seventeen by twenty-two inches, text uses twenty-five by thirty-eight inches, cover uses twenty by twenty-six inches, and index uses twenty-five point five by thirty point five inches. Pair the free browser run on this page with the priced API when you need the identical mathematical result inside an automated pipeline without re-implementing basis tables yourself.

Where gsm and basis pounds fit in print, publishing, and software

On this page the work runs entirely in your browser; through the API each successful lookup costs $0.002, failed validation is not charged, and nothing is stored after the response returns. That split — free interactive exploration and a priced, identical API — matches the rest of the KIT tier-A catalog and lets you move from a shop-floor demo to an automated pipeline without changing the mathematical result.