To convert microsiemens to millisiemens, multiply by 0.001. That factor is the whole relationship: both units measure how readily current passes — the reciprocal of resistance, so the conversion is a proportion with no offset and no substance-specific constant.
One milli siemens is one thousandth of a siemens (1e-3 siemens). Microsiemens per centimetre is how water conductivity is reported, so µS is the unit on every aquarium and hydroponics meter.
Two tables follow: rounded steps for quick lookup, and a set of real reference quantities converted into millisiemens, which is usually more useful than the bare number.
The formula
microsiemens- The amount you are converting, in microsiemens
0.001- The exact number of millisiemens in one microsiemens
millisiemens- The converted result
How it works, step by step
- Enter the value in microsiemens.
- It is multiplied by 0.001, the exact factor between the two units.
- The answer is shown in millisiemens, with the reverse conversion beneath it.
- Check the reference table if you want a figure of comparable size.
Worked examples
Hydroponic nutrient solution, per cm: 2000 µS in millisiemens
At 2000 µS (hydroponic nutrient solution, per cm), the same quantity in millisiemens is 2000 × 0.001 = 2 mS. One microsiemens is 0.001 millisiemens, so the numbers shrink as expected.
Distilled water, per cm: 0.055 µS in millisiemens
At 0.055 µS (distilled water, per cm), the same quantity in millisiemens is 0.055 × 0.001 = 5.5e-05 mS. One microsiemens is 0.001 millisiemens, so the numbers shrink as expected.
How to read your score
Frequently asked questions
How many millisiemens are in one microsiemens?
Exactly 0.001. Every figure on this page is that one number multiplied by your input, so the only rounding is at the display step.
What is the formula to convert microsiemens to millisiemens?
millisiemens = microsiemens × 0.001. Reversed, microsiemens = millisiemens ÷ 0.001, which is the same as multiplying by 1000.
Which is the bigger unit, the microsiemens or the millisiemens?
The millisiemens. One microsiemens is only 0.001 of a millisiemens, so it takes 1000 microsiemens to make one millisiemens.
What does this quantity actually measure?
Both units measure how readily current passes — the reciprocal of resistance. That is why a single factor is enough: there is no temperature offset and no material property involved, unlike conversions that cross between different quantities.
What is a microsiemens?
Microsiemens per centimetre is how water conductivity is reported, so µS is the unit on every aquarium and hydroponics meter.
What is a millisiemens?
One milli siemens is one thousandth of a siemens (1e-3 siemens).
Why does my answer differ from another converter?
Almost always because the other tool rounded the factor before multiplying. This page keeps full double precision through the calculation and rounds only for display, and it prints the factor it used so you can see where any difference came from.
Microsiemens to millisiemens reference tables
| Microsiemens | Millisiemens |
|---|---|
| 0.5 µS | 0.0005 mS |
| 1 µS | 0.001 mS |
| 2 µS | 0.002 mS |
| 3 µS | 0.003 mS |
| 5 µS | 0.005 mS |
| 10 µS | 0.01 mS |
| 20 µS | 0.02 mS |
| 25 µS | 0.025 mS |
| 50 µS | 0.05 mS |
| 75 µS | 0.075 mS |
| 100 µS | 0.1 mS |
| 250 µS | 0.25 mS |
| 500 µS | 0.5 mS |
| 1000 µS | 1 mS |
| 5000 µS | 5 mS |
Exact factor: 1 microsiemens = 0.001 millisiemens.
| Quantity | µS | mS |
|---|---|---|
| Distilled water, per cm | 0.055 µS | 5.5e-05 mS |
| Drinking water, per cm | 500 µS | 0.5 mS |
| Hydroponic nutrient solution, per cm | 2000 µS | 2 mS |
| Sea water, per cm | 5e+06 µS | 5000 mS |
| 1 kohm resistor | 1000 µS | 1 mS |
| 10 ohm resistor | 1e+05 µS | 100 mS |
Published reference values, converted with the same factor this page uses.