Is washing soda and washing powder the same thing?

No, they are not the same. Washing soda is a single, well-defined chemical: sodium carbonate decahydrate (Na₂CO₃·10H₂O). It is a strong alkali used to raise pH and soften hard water by precipitating calcium and magnesium ions. Because it is highly basic, it helps saponify fats and cut grease, which is why it appears as a “builder” in many cleaning formulations. However, used alone on delicate fabrics, it can be harsh and may fade dyes or weaken fibres if overdosed.

Washing powder, by contrast, is a formulated detergent a blend of surfactants (to lift soils), builders (often including sodium carbonate), enzymes (for proteins and starches), optical brighteners, oxygen-based bleaches, anti-redeposition agents, and fragrances. This multi-component design targets a wide spectrum of stains at typical wash temperatures while protecting textiles and machine parts. The builder portion conditions the water; the surfactants emulsify oils; enzymes digest stain molecules; and stabilizers keep soils suspended until rinsed.

For household laundry, washing powder is the complete solution; washing soda is best used as an additive for very hard water or stubborn grease, or for pretreating heavily soiled items (always follow garment care labels and dose guidelines). In summary: washing soda is a single alkaline chemical; washing powder is a balanced, fabric-safe cleaning system that may contain washing soda among other actives.

Quick differences:

• Chemistry: Single compound vs. formulated blend.
• Function: Builder/softener vs. full detergent action.
• Fabric care: Potentially harsh alone vs. optimized for textiles.