SpecBase

Calculators

Two tools, both computing from closed-form geometry rather than interpolating a table — so a non-standard size gets the same accuracy as a standard one. Neither is a text box and a number: each carries the extra quantities that decide how a figure is actually used.

Metal weight calculator

Pick a shape, enter dimensions, choose a material. 16 materials across 10 section types.

  • Multi-line bill of materials — one row per section, totalled
  • Reverse lookup — target mass in, required length out
  • Dual units — metric and imperial, converting the value rather than snapping to a stock size
  • Formula and derivation shown for every result, so the number can be checked

10 shapes · 16 materials · BOM · reverse lookup

Pipe weight calculator

Choose a nominal size and schedule, or enter a custom outside diameter and wall. Mass, bore and the quantities a printed chart omits.

  • {sizes} nominal sizes with every tabulated estimate wall
  • Water capacity — the figure that sizes a hydrostatic test
  • Coating area — external surface per metre
  • Material-aware — 304 pipe is 1.9 % heavier than carbon steel for the same geometry

31 sizes · 17 schedules · custom OD/wall

What makes these different from a text box

Any weight calculator returns a number. These three properties are what makes the number usable — and they are the reason each tool is a page rather than a widget.

Computed, not interpolated

The area comes from the shape’s own formula, evaluated for whatever numbers you enter. There is no lookup table behind it and no rounding between rows, so a 43 mm bar is computed exactly rather than estimated from the 40 mm and 50 mm rows.

Density is a choice, not a constant

Most calculators assume 7,850 kg/m³ for everything. That is right for carbon steel and wrong for the other fifteen materials here — aluminium is a third of it, lead is 1.44 times it. The material selector changes the answer.

The arithmetic is shown

Every result comes with the formula and the substitution behind it. A weight you cannot check is a weight you have to trust; a weight with the working shown is one you can verify in ten seconds, which matters when the number goes on an order.

Not built yet, and why

A shorter list than it could be, because a thin tool is worse than an absent one. These are the gaps, and the reason each is not here:

Pressure rating calculator
Wall thickness for pressure is governed by a piping code (ASME B31.3 for process, B31.1 for power, B31.9 for building services) and depends on the design pressure and temperature, a corrosion allowance, the manufacturing tolerance, a weld joint factor and the material’s allowable stress at temperature. A simplified version would produce a number that looks authoritative and is wrong for the case being checked. Use the code.
Section properties (I, Z, r)
Second moment of area, section modulus and radius of gyration depend on the exact nominal shape, including root radii and flange taper — which is why the standards that publish them publish the whole geometry, not a formula. Our parametric size series is round-numbered geometry for estimating, and putting plausible section properties next to it would be worse than the gap.
Bolt torque and preload
Torque tables are only meaningful with a friction coefficient, and friction depends on coating, lubricant, thread condition and the number of re-uses. A table without those assumptions is a number people will use anyway. The standards give the method; the joint gives the inputs.
Material cost calculator
It would need live prices for sixteen materials in several product forms, and a stale price is actively misleading in a way a stale density is not — density does not move 20 % in a quarter, steel does. Cost belongs wherever the reader actually buys, with the reader’s own price.
Flange, fitting and valve dimensions
A genuinely useful next cluster, and a real project rather than a calculator: ASME B16.5 flanges alone are a dimensional standard with pressure classes, facing types and a hundred tabulated sizes. It is on the roadmap as its own dataset, not as a tab on an existing tool.
General unit converter
Already solved everywhere, including by the browser address bar, and a version here would be a page with no data behind it. The unit constants this site does use are documented on the cross-reference page for anyone who wants to check a figure by hand.
If one of these would be useful to you

Tell us via the correction and request form. A tool that needs data we would have to publish accurately (pressure ratings, section properties) is a much bigger job than a calculator, which is why they are deferred rather than simply absent.

Prefer the tables?

Every calculator has a static reference table underneath it for the same reason: a table can be scanned, compared and printed, and a calculator cannot. The two are complements.

The same data as CSV

Generated at build time from the same source modules the calculators and tables use.

Metal weight (CSV · long format) Pipe dimensions (CSV · 367 rows) Densities (CSV · 16 materials)

All downloads, with column definitions, are on the downloads page.

Frequently asked questions

Do the calculators work without JavaScript?

The pages do, the interactivity does not. Every calculator page server-renders a full reference table of the same data at standard sizes, so with scripts disabled you still get the static table, the formula, the worked derivation and the FAQ — which is most of the value. What you lose is entering your own dimensions. The interactive layer is progressive enhancement layered on top, not the page itself.

Why are there only two calculators?

Because there are only two calculations in this subject. Metal weight is area × length × density, and a pipe is a special case of the same thing where the area happens to be an annulus. A third tool that re-labelled one of those would be a page built for keywords rather than for use. The tools that are genuinely missing — a pressure rating calculator, a section-property lookup, a bolt and flange reference — need data we do not publish, so they are listed below as not-yet rather than shipped thin.

Can I calculate a whole bill of materials?

Yes, in the metal weight calculator. Add a line per section, each with its own shape and dimensions, and the material selector applies to the whole list — which is how a take-off actually works: one material call-out, many sections. The list exports as CSV.

What does the reverse lookup do?

It inverts the calculation. Instead of asking what a given length weighs, it asks what length reaches a given mass — the constraint that governs a lot of real fabrication work: crane capacity, shipping weight bands, axle limits, a pallet limit. A printed table cannot answer it at all, because the question is about your limit rather than about a standard size.

Reference data

The tables these calculators are built on.

Data source and method

Both calculators evaluate the same functions used to build the static tables on this site — there is one calculation path, so a calculator result and the table row beside it cannot disagree. Pipe dimensions come from ASME B36.10M / B36.19M; densities from material specifications.

  • Elementary plane geometry. The circle, polygon and hollow-section area formulas.
  • ASTM material specifications for each grade named in the material entry (A36, A240/A276, B209/B211/B221, B152/B16/B505, B265/B348, A48, B29, D1784, D3350).
  • ASME B36.10M — Welded and Seamless Wrought Steel Pipe (dimensional tables).
  • BIPM / NIST definitional constants: international inch = 25.4 mm, foot = 0.3048 m, pound = 0.45359237 kg.

Dataset version 2026.09.1 · dimensions last verified against source 2026-09-21. Found an error? Report it — corrections are issued with a version bump.