About Alphaflat

One colour calculation, clearly bounded.

Alphaflat helps a designer or web author turn a specified foreground opacity over a known flat background into a fixed opaque colour token. The useful output is a hex or RGB value you can copy, with enough arithmetic to inspect how it was obtained.

What this page does

It uses normal source-over with one opaque background, directly on encoded sRGB numbers. Decimal opacity and channel results are preserved as exact fractions. The separate 8-bit export rounds to nearest integer, with an exact half rounded upward. A solid swatch shows that exported result without trying to reproduce a transparent-layer scene.

Where the model stops

This is not a layer-stack editor or a colour-management application. It does not accept transparent backgrounds, alpha-bearing hex, colour profiles, blend modes, images or uploads. It does not sample pixels, recover an unknown foreground, predict print or paint, or give a contrast or accessibility verdict. Linear-light computation is outside this version.

Your browser or editing application may use different colour spaces, rounding, display conversion or rendering rules. The numeric result here is an explicitly chosen model rather than a promise about those systems. Test a token in its actual context when visual matching matters.

Free to use

The calculator and guides are available without an account, subscription or payment. Advertising may support the site later if it is configured and approved, but this prepared release has no active advertising, analytics beacon or consent-management loader. No visitor, approval or income result is claimed by the source.

Feedback

Alphaflat belongs to the owner's free-tool portfolio. The contact page uses an existing shared forwarding alias, not a new separate mailbox. If a calculation seems wrong, a small nonsensitive input example and the result you expected are more useful than a screenshot alone.