Serial Dilution Calculator
Several small dilutions are more accurate than one large one. Ten-fold three times gives a thousand-fold, and because the factors multiply, one extra step moves the concentration by a whole order of magnitude.
Your numbers
Target %
0.1%
Total dilution
1,000×
ppm
1,000
Formula
Total dilution = Dilution factor ^ Count
Each transfer has to be measured carefully. Errors multiply along with the factors, so a small slip compounds across three steps.
What to enter
| Input | Default | Accepted range |
|---|---|---|
| Dilution factor (×)How many times the concentrate was expanded — 1 part to how many. | 10 | 0 and up |
| CountA plain count of items; it often ends up as the denominator. | 3 | 0 ~ 20 |
| Concentration (%)How much of the whole is solute. | 100 | 0 and up |
Step by step
Quick reference table
Results when only Dilution factor (×) changes and everything else stays put.
| Dilution factor (×) | Target % (%) | Total dilution (×) | ppm |
|---|---|---|---|
| 5 | 0.8 | 125 | 8,000 |
| 7.5 | 0.237037 | 422 | 2,370.37 |
| 10 | 0.1 | 1,000 | 1,000 |
| 15 | 0.02963 | 3,375 | 296.3 |
| 20 | 0.0125 | 8,000 | 125 |
What each result means
| Result | At default values |
|---|---|
| Target % (%)The concentration you want; lower means add water, higher means add solute. | 0.1 |
| Total dilution (×)Every step’s factor multiplied together. | 1,000 |
| ppmParts per million; 1 ppm is 0.0001%. | 1,000 |
Common mistakes
Each transfer has to be measured carefully. Errors multiply along with the factors, so a small slip compounds across three steps.
Glossary
- Dilution factor
- How many times the concentrate was expanded — 1 part to how many.
- Count
- A plain count of items; it often ends up as the denominator.
- Concentration
- How much of the whole is solute.
- Target %
- The concentration you want; lower means add water, higher means add solute.
- Total dilution
- Every step’s factor multiplied together.
- ppm
- Parts per million; 1 ppm is 0.0001%.
Frequently asked questions
Q. How is Serial Dilution Calculator calculated?
Total dilution = Dilution factor ^ Count — Several small dilutions are more accurate than one large one. Ten-fold three times gives a thousand-fold, and because the factors multiply, one extra step moves the concentration by a whole order of magnitude.
Q. Can you walk through an example?
With Dilution factor 10×, Count 3, Concentration 100%, the answer is Target % 0.1%.
Q. What do I need to enter?
Enter Dilution factor, Count, Concentration. The result recalculates as you type, and an empty box counts as zero.
Q. How much does the answer move if I change a number?
Changing only Dilution factor (×) moves the answer to Dilution factor (×) 5 → Target % (%) 0.8 and Dilution factor (×) 20 → Target % (%) 0.0125. The table below lays out five steps.
Q. How are the numbers rounded?
Money is shown to the nearest whole unit, percentages to one decimal place and everything else to two. What you see is rounded; the calculation itself carries the unrounded value forward.
Q. Anything to watch out for?
Each transfer has to be measured carefully. Errors multiply along with the factors, so a small slip compounds across three steps.
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