SpecBase

Report a data error

8,063 computed values and 57 dimensional tables is enough surface that something will eventually be wrong. A precise report is the most valuable contribution anyone can make to a reference like this.

What to send

The five facts below turn a report into a fix. Without them most reports become an exchange of four emails to establish which figure was being looked at.

Page URL:
Value on the page:
What it should be:
Dimensions used (mm or in):
Material and density used (kg/m³ or lb/in³):
Source for the correction:

The last two are the important ones. Density assumptions account for most disagreements of about 0.1 %, so knowing which density you used resolves them immediately; and a source — the standard, a mill data sheet, or your own working — lets the correction be verified rather than applied on trust.

Open a pre-filled email → Read the method first

Or write to semseoueo@gmail.com.

What happens next

  1. The figure is checked against the source cited on methodology, and against the test suite’s published-reference values where one exists.
  2. If it is wrong, it is corrected in the data module — one place, which is why a single fix moves every page, every calculator and every CSV at once.
  3. The dataset version is bumped, currently 2026.09.1 (reviewed 2026-09-21). The version drives the sitemap’s lastmod, so a correction is visible to crawlers as a genuine change.
  4. The build runs its baseline assertions and the output guard before deploying. If a correction breaks either, the deployment stops rather than shipping.
If the disagreement is in the last digit

Check the density first. Printed weight charts are commonly calculated at 0.2833 or 0.2836 lb/in³ — about 7,844 or 7,850 kg/m³ — and rounded. This site computes from the material specification density, so a carbon-steel figure can legitimately differ in the fourth significant figure, and a 304 stainless figure runs about 1.9 % heavier than the same geometry in steel. That is not an error to report; it is the difference being made explicit.

Other reasons to get in touch

Requesting a material or a size
Adding a material or a section shape is a data change rather than a rebuild — the page matrix expands on its own. Genuinely useful suggestions are welcome; tell us what you would use it for, since a material that appears in no take-off adds a hundred pages of noise.
Requesting a tool
See the calculators page first — the tools that are missing are listed with the reason they are missing, and that reason may already be the answer.
Using the data somewhere
Always interesting to hear, and it helps prioritise. The data is free to use with attribution; see disclaimer for what is ours to license and what is the standards’.
Something on the site not working
Broken layout, a table that will not scroll on a phone, a calculator that stopped responding. A screenshot and the page URL is enough.

What this page will not do

There is no contact form, because there is no backend and a form that posts nowhere is worse than an email address. Nothing you send is stored anywhere beyond the ordinary mailbox, and no part of the site sets a cookie or runs an analytics script — see privacy.

Reference data and tools

In case what you were looking for is already here.