About SpecBase

What this is

A weight table is not data, it is arithmetic. Cross-sectional area comes from the shape’s own formula, density comes from the material’s specification, and the two multiplied give the answer. Every page here does that multiplication for one material and one shape across a full size series, and shows the working — so a figure can be checked rather than trusted.

That approach has one consequence worth stating: because nothing is read from a lookup table, a non-standard size is exactly as accurate as a standard one. A 43 mm bar is computed, not interpolated between the 40 mm and 50 mm rows.

The same identity covers pipe. A pipe is an annulus, so the same code path returns mass, bore, internal volume and external surface — which is why this site can give you the two quantities a printed pipe chart omits, the ones that actually decide a hydrostatic test charge and a coating order.

How it is built

Static, with no backend

Generated ahead of time and served as files. There is no database, no API to rate-limit and nothing to keep running, which also means nothing to go down at the moment you need a number.

Calculators that degrade

The interactive tools are progressive enhancement over server-rendered tables. With JavaScript disabled you still get the table, the formula, the worked derivation and the FAQ — you lose the ability to type your own dimensions, not the data.

One calculation path

The calculators, the tables, the CSV downloads and the test suite all call the same functions. There is no second implementation to drift out of step, and a correction lands everywhere at once.

Tested on every build

52 assertions run before the pages are generated, and an output guard runs after. Either failing fails the build, which leaves the previous deployment serving. Details on methodology .

No tracking

No cookies, no analytics, no third-party requests of any kind. See privacy .

What this is not

The site is more useful for being explicit about its boundaries than it would be by quietly covering them:

• Not a substitute for the standards. We publish dimensional facts and computed values. We do not reproduce any standard’s text, notes, tolerances or commentary, and where a standard is the authority we say so and link to it.
• Not a strength or pressure rating. Weight is a mass property. Nothing here tells you whether a part is safe, and no weight figure can.
• Not a mill certificate. Densities are nominal engineering values. Real material varies, and cast and formulated materials vary a lot.
• Not a section-property table. Second moment of area, section modulus and radius of gyration belong to the mill’s own table for a named shape — UPN, IPE, HEA, AISC W/C/MC. Our parametric size series is round-numbered geometry for estimating.
• Not a place to guess. Where a calculation needs inputs we cannot supply honestly — a friction coefficient for bolt torque, live material prices, a piping code’s design case — the tool is not published, and the reason is written down on the calculators page instead of the page being shipped thin.

Who it is for

Fabricators pricing a job, estimators doing a take-off, designers checking a section, students learning why a 2-inch pipe is not 2 inches, and buyers sanity-checking a supplier’s figure. The common thread is someone who needs a defensible number quickly and wants to see where it came from.

Corrections and requests are genuinely welcome — a reference is only as good as its error reporting. See report a data error .