How to read detergent information (UK)

Many members are unsure how much detergent to use for their nappy washing and general laundry. Laundry detergent is essential for cleaning heavily soiled items such as nappies. It is important to choose an effective detergent, preferably with enzymes, and use enough of it to ensure clean laundry.

Our UK detergent guide will help you understand how much detergent to use.

Select a detergent

The full UK index contains 43 different detergents and is available exclusively to our patrons and website members with a current quarterly or annual subscription. Not all detergents perform at the same level, there can be large variations between different products. The different raw materials included in the detergent as well as the amount of detergent used will determine its effectiveness.

Don’t have time to read the entire index? We have collated our favourite UK detergents together, find one that suits your family.

Figuring out an initial dose

Dosing accurately relies on three things:

1. Amount of soiling (light, medium or heavy)
2. Water hardness (soft, moderate or hard)
3. Drum size

To calculate how much detergent is needed for both pre-wash and main wash first work out the total amount required for the main wash.

Calculate your main wash dose

Start with the suggested heavily soiled dose for your machine size and water hardness. Remember, this is a starting point, you might need to use more detergent depending on your water hardness and the soiling level of your items.

Note: the dosages in the graphics below are specific to the detergent used in this example. Please check your detergent label carefully.

Turn to the dose instructions on the side/back of the detergent label (both powders and liquids).

1. Establish the water hardness

Water hardness varies all over the United Kingdom. Most people know their water hardness, especially if they live in a hard water area. If unsure, visit your local water authority’s website or search online for your area + water hardness.

2. Always treat nappies as heavily soiled laundry.

Nappies are very dirty laundry, for this reason, always refer to the appropriate dosing for heavy soiling.

3. Find the appropriate amount for heavy soiling in relation to water hardness.

Follow the guide for the heavily soiling column for the appropriate water hardness, see the corresponding dose.

In this example, the amount needed to wash nappies in hard water is 190 mL

4. Add the additional amount specified for larger machines.

All mainstream detergents will recommend adding extra detergent for machines larger than 5kg. This will be specified somewhere on the pack.

In this example, if you are washing nappies in an 8 kg machine in a hard water area, you would add an additional 40mL to the 190mL specified. This means a total of 230mL will be used for the main wash.

If the machine is 10kg or bigger, add twice the additional amount.

Calculate your first wash (prewash) dose

Use one-third (1/3) of the suggested main wash dose if you run a first wash daily or half (1/2) of the dose if you run it every second day.

Measuring detergent

UK detergent is dosed using metric volume, millilitres (mL), and instructions often also include a conversion for mL to grams.

You can use any container with mL measurements to measure detergent. Many members use measuring jugs or unused baby bottles. Unilever and Proctor & Gamble send out free dosing devices on request.

Adjusting your detergent dose

More detergent is needed if the load has more soiling, or if you are relying more on detergent to do the cleaning. Examples where you likely need more detergent include having multiple children in cloth, older children, hard water, or using a larger machine. Increase detergent until there are sufficient suds in the wash phase of the cycle.

If nappies and general laundry do not appear to be cleaning well consider increasing the amount of detergent. Increase this in 30-40 mL increments.

Each wash cycle is different, the level of soiling is never identical. You might have the same cycle length and water temperature but the the soiling and staining of each load is different. This means you need to be mindful of when to adjust the detergent dose (and chemical factors).

~ Anastasia, Environmental Scientist and founding Facebook group admin