Concentrated Laundry Detergent: How to Calculate the Cost per Wash, Not per Bottle
Concentrated laundry detergent often looks more expensive, because its price on the shelf or on the product page can be higher. But you are not really buying a litre of liquid — you are buying a certain number of washes. So the right question is not “how much does the bottle cost?” but how much one full wash costs at the correct dose. In this article, we show you how to work that out in a minute and how to compare different detergents fairly.
Why the bottle price is misleading
Two detergents can come in the same size bottle, yet one of them is more concentrated. If one needs 30 ml per wash and the other 70 ml, the cheaper bottle may run out twice as fast. That is why the real price only becomes clear once you work out the dose per wash.
If you are not yet sure about dosing, start with our guide on how to dose laundry detergent correctly. It is one of the most important articles, because overdosing pushes up the cost directly 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 = about 33 washes |
| Bottle costs €14.90 | €14.90 / 33 = about €0.45 per wash |
In practice, calculate it like this:
- Find the dose for a normal wash on the label (moderately soiled laundry, a full but not overloaded drum).
- Check which water hardness that dose is given for, and pick the one that matches your water.
- Divide the bottle volume in millilitres by that dose — this gives you the real number of washes.
- Divide the bottle price by the number of washes.
Pay attention to the words “up to”. A label saying “up to 33 washes” refers to the number you get with the basic dose. If you regularly pour in more, the real number of washes will be lower.
Comparison example: three detergents
The figures below are illustrative, just to show the logic:
| Detergent | Price and volume | Dose | Washes | Cost per wash |
|---|---|---|---|---|
| A (not concentrated) | €8.90 / 1 l | 70 ml | about 14 | about €0.64 |
| B | €12.90 / 1.5 l | 50 ml | 30 | about €0.43 |
| C (concentrated) | €14.90 / 1 l | 30 ml | about 33 | about €0.45 |
| C, but dosed at 60 ml | €14.90 / 1 l | 60 ml | about 16 | about €0.93 |
Here the cheapest bottle gives the most expensive wash, and the concentrated detergent loses its whole advantage if you eyeball the dose and pour in twice as much.
That is why, when you assess a laundry detergent, it is worth looking not just at the price but at how many real washes you get from one bottle.
How to compare liquid detergent with powder and pods
- Powder. Calculate in grams: the pack weight divided by the dose in grams. For example, a 3 kg pack and a 75 g dose give 40 washes.
- Pods. The cost per wash equals the price of one pod. But you cannot reduce the dose, so when you wash a half load, part of the product is simply wasted.
- Liquid detergent. The easiest to adjust: for a smaller load or soft water you can use less.
You can read more about the differences in our article Washing powder vs liquid detergent.
What changes the real dose?
| Situation | Dose |
|---|---|
| Soft water, half load, lightly soiled clothes | Less than usual |
| Medium water hardness, full drum | Normal dose |
| Hard water or very dirty clothes | Slightly more |
| One obvious stain | Normal dose plus pre-treating the stain |
If your water is hard, it is worth knowing how it affects the result — we cover this in the article Laundry detergent in hard water.
The most common mistakes with concentrated detergent
- Pouring by eye. This is the most common reason detergent runs out too quickly.
- Increasing the dose when it is not needed. A large load, very dirty clothes or hard water may call for a little more detergent, but that should not become the norm for every wash.
- Confusing fragrance with cleanliness. A strongly scented fabric is not necessarily better washed.
- Using a short programme with too much detergent. A short cycle may not have time to rinse out the excess.
- Comparing different things. One detergent’s cost is calculated with the minimum dose, another’s with the maximum. Compare under the same conditions.
How to lower your cost per wash
- Always measure with the cap or a measuring cup.
- Wash a full but not overloaded drum — a half-empty drum makes every item more expensive to wash.
- Pre-treat stains instead of raising the dose for the whole load.
- Choose 30–40 °C for everyday clothes: a lower temperature also means lower electricity use.
- Clean your washing machine regularly so that residue and odours do not force you to rewash.
Why concentrated liquid detergent is practical for everyday use
Liquid detergent disperses in water faster, so it is often more convenient at 30–40 °C and in shorter programmes. It is also easy to measure accurately, which directly determines the cost per wash.
With Ecozyme, the practical principle is simple: start with the recommended dose, and for tougher stains use pre-treatment or let the detergent sit on the stain. One litre of Ecozyme enzyme detergent lasts up to 33 washes, and it works from 30 °C. That way the detergent works where it is needed instead of being poured in at double the amount for every wash.
Related Ecozyme guides
- How to dose laundry detergent correctly
- Washing powder vs liquid detergent
- Washing at low temperatures
- Liquid laundry detergent for everyday washing
Frequently asked questions
Is concentrated detergent really cheaper?
Not always, but often — as long as you dose it as recommended. What matters is not the bottle price but the number of washes. If you overdose, any detergent loses its advantage.
How do I calculate the cost per wash of Ecozyme detergent?
One litre of Ecozyme detergent lasts up to 33 washes, so divide the bottle price by 33. If you often wash half loads and use less, each wash will cost even less.
Can I use less than the recommended dose?
Yes, if the drum is not full, the clothes have only been worn briefly or your water is soft. If an odour or a greyish tinge remains after washing, increase the dose slightly.
Why does my detergent run out faster than promised?
Usually because it is poured without measuring, the dose is chosen for hard water when your water is medium, or the dose is increased every time “just in case”.
Is a bigger pack always better value?
Not necessarily. A bigger pack sometimes has a lower price per litre, but if the product is less concentrated, the cost per wash may be higher. Always recalculate based on the dose.
Summary
Cost per wash = bottle price / (volume / dose). Compare detergents under the same conditions, measure the dose, adjust it to your water hardness and load size, and pre-treat stains. That is when a concentrated detergent really pays off.
To judge the real price, count washes, not litres. You will find the Ecozyme range here: laundry detergent for clothes.
