Dilution Ratios Explained — Module 1

Free Taster Micro-Course. This module gives you a practical introduction to dilution ratios for cleaners. For full professional training with CPD certification, explore our paid courses.

What you'll learn in this module

  • What a dilution ratio is and how to read one
  • Why correct dilution matters for safety, effectiveness, and cost
  • The difference between dilution ratio and concentration

What is a Dilution Ratio?

A dilution ratio tells you how many parts water to add to one part chemical concentrate. It is written as 1:10, 1:20, 1:100, and so on. The first number is always the chemical, the second is always the water.

So a ratio of 1:10 means one part chemical to ten parts water. A ratio of 1:100 means one part chemical to one hundred parts water — a much weaker solution.

Key point: The higher the second number, the more diluted the solution. 1:100 is weaker than 1:10.

Why It Matters

Getting the dilution ratio wrong has real consequences in three areas:

  • Safety: Using a chemical at too high a concentration can cause skin burns, respiratory irritation, and surface damage. This is a COSHH risk.
  • Effectiveness: Over-diluting a chemical means it may not kill bacteria, remove soiling, or perform as intended.
  • Cost: Over-concentrating wastes expensive chemical. Over-diluting means you use more product to get the same result. Both cost you money.

How to Read a Dilution Ratio

Dilution ratios are printed on the product label and in Section 7 of the Safety Data Sheet. They are sometimes shown as a ratio (1:20), sometimes as a percentage (5%), and sometimes as a volume per litre (50ml per litre). These all mean the same thing — Module 2 shows you how to calculate each one.

Remember: Always follow the manufacturer's stated dilution ratio. Do not guess. The ratio is set for a reason — safety, efficacy, and compliance.
Disclaimer: This micro-course provides a general introduction to dilution ratios for cleaning chemicals. It is not a substitute for full professional training. Always follow manufacturer guidance and refer to current HSE guidance for your specific workplace.