Stain Treatment Guide Calculator

Tannin stains (coffee, wine) normally call for warm water, but the calculator drops that to cold specifically when the fabric is wool or silk. Heat can permanently set a tannin stain and can also damage delicate protein fibers like wool and silk, so the calculator avoids both risks at once by recommending cold water for that specific combination.

Soak time starts from a stain-specific baseline and is then multiplied by an age factor: fresh stains use a factor of 1, set stains double it, and old stains quadruple it. That age multiplier is also multiplied by your entered severity level, so an old, heavy stain can require many times the soak time of a fresh, light one of the same type.

Treatment method is assigned per stain type based on how each stain class actually breaks down chemically: protein stains get enzyme treatment, tannin and dye stains get oxidizing agents, oil and grease get solvent treatment, and rust gets acid-based treatment. Fabric type and stain age don't change which method is recommended — only water temperature and soak time.

Removal probability starts at a stain-specific base rate and is reduced by three separate factors: stain age (older stains subtract more), severity above the lightest level, and an additional penalty if the fabric is delicate wool or silk. All three reductions stack, so an old, severe stain on a delicate fabric can end up well below that stain type's base removal rate.

It's a rough derivation from the estimated removal probability, not a guarantee of how many washes will clear the stain. Real-world results depend heavily on the specific stain-removal product used and on prior laundering history — especially whether the garment has already been through a hot dryer cycle, which can set a stain in a way this calculator has no way to detect.