Laundry Detergent Dose
Work out the right detergent dose for your load and water hardness.
About Laundry Detergent Dose
Detergent dose scales with load size on a per-kilogram basis, then rises with water hardness because hard water consumes more surfactant. Using the right dose saves money and prevents residue buildup, especially in hard-water areas where guessing leads to overuse.
Formula
Laundry Detergent Dose
Dose = load weight x dose per kg x hardness multiplier
- hardness
- Hard water needs more detergent to lather
Worked example
With the default values below, Laundry Detergent Dose returns Dose per Load of 69.0. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Load weightminimum 0 kg
- 6 kg
- Dose per kgminimum 0 ml/kg
- 10 ml/kg
- Water hardnessone of Soft, Medium, Hard
- Medium
- Loads per weekminimum 1
- 5
Results
- Dose per Load
- 69.0 ml
- Hardness Multiplier
- 1.15
- Weekly Detergent
- 345.0 ml
- Monthly Detergent
- 1.50 litres
Step by step
- 1Values used
- 2Laundry Detergent Dose
- 3Dose per Load= 69.0 ml
- 4Hardness Multiplier= 1.15
- 5Weekly Detergent= 345.0 ml
- 6Monthly Detergent= 1.50 litres
Assumptions and limits
- The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax or compounding frequency into account.
- Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is Laundry Detergent Dose calculated?
Dose = load weight x dose per kg x hardness multiplier Detergent dose scales with load size on a per-kilogram basis, then rises with water hardness because hard water consumes more surfactant.
Why does Laundry Detergent Dose matter?
Using the right dose saves money and prevents residue buildup, especially in hard-water areas where guessing leads to overuse.
What values do I need to enter?
This calculator takes 4 inputs: Load weight, Dose per kg, Water hardness, Loads per week. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.