Concentrated Laundry Detergent: How to Calculate the Cost per Wash, Not per Bottle

2026-07-04 3 min. skaitymo

Concentrated laundry detergent often looks more expensive because its price on the shelf or product page may be higher. But detergent isn't bought simply as a litre of liquid — it's bought as a certain number of washes. So the right question isn't "how much does the bottle cost?", but how much one full wash costs at the correct dose.

Why is the bottle price misleading?

Two different detergents may have the same volume, but one will be more concentrated. If one wash needs 30 ml of one product and 70 ml of another, the cheaper bottle may run out twice as fast. That's why the real price only becomes clear once you work out the dose per wash.

If you're still unsure about dosing, first read our guide to dosing laundry detergent correctly. It's one of the most important articles, because overdosing directly increases the cost and can leave residue in fabrics.

How to calculate the cost per wash

The formula is very simple: the bottle price divided by the number of washes. You get the number of washes by dividing the bottle volume by the recommended dose.

Example	Calculation
1 l bottle, 50 ml dose	1000 ml / 50 ml = 20 washes
1 l bottle, 30 ml dose	1000 ml / 30 ml = approx. 33 washes
Bottle costs 14,90 €	14,90 € / 33 = approx. 0,45 € per wash

So when assessing a laundry detergent, it's worth looking not only at the price but also at how many real washes you get from one bottle.

The most common mistakes with concentrated detergent

Pouring it in "by eye". This is the most common reason detergent runs out too quickly.
Not increasing the dose only when needed. A large load, very dirty clothes or hard water may call for a little more product, but this shouldn't become the norm for every wash.
Confusing scent with cleanliness. A strongly scented fabric isn't necessarily better washed.
Using too large a dose on a short programme. A short cycle may not have time to rinse out the excess.

Why is concentrated liquid detergent convenient for everyday use?

Liquid detergent disperses faster in water, so it is often more convenient at 30–40 °C and on shorter programmes. You can read more about the benefits of liquid detergent in the article Washing Powder vs Liquid Detergent.

With Ecozyme, the practical principle is simple: start with the recommended dose, and for tougher stains use pre-treatment or apply the product directly to the stain and leave it to work. That way the detergent works where it's needed, rather than simply being poured in at double the amount for every wash.