White is a color category, not a fabric
A white cotton towel, a white polyester shirt and a white lace garment can need different temperatures. Sort whites by fabric and care instructions before choosing a setting. Do not use color alone as permission for hot water or bleach.
Warm is a useful starting point for many ordinary whites
For normally soiled durable white garments, warm water is a practical general starting point. Heavier durable cotton items may allow hotter water, while delicate whites or items with elastic and trim may require cool settings. The care label is the upper limit.
Treat stains before raising temperature
Stain chemistry matters. Protein stains can need a different first response than oily or tannin stains. Pretreat with a compatible product and then use the warmest wash allowed by the item and treatment directions.
Use the finder with a label cap
The Wash Temperature Finder can provide a reviewed starting point in Celsius and Fahrenheit. Enter a lower care-label maximum when one is printed so the result is capped instead of overriding the garment.
Garment care labels, appliance manuals and laundry-product directions can be more specific than a general guide. Use them when they set a tighter limit.