One millisiemens is exactly 0.001 siemens, so converting millisiemens to siemens is a single multiplication. Enter any figure and the result appears as you type — the arithmetic runs in your browser, so nothing is sent anywhere.
The siemens is the reciprocal of the ohm: one siemens is one amp per volt. One milli siemens is one thousandth of a siemens (1e-3 siemens).
Two tables follow: rounded steps for quick lookup, and a set of real reference quantities converted into siemens, which is usually more useful than the bare number.
The formula
millisiemens- The amount you are converting, in millisiemens
0.001- The exact number of siemens in one millisiemens
siemens- The converted result
How it works, step by step
- Enter the value in millisiemens.
- It is multiplied by 0.001, the exact factor between the two units.
- The answer is shown in siemens, 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: 2 mS in siemens
At 2 mS (hydroponic nutrient solution, per cm), the same quantity in siemens is 2 × 0.001 = 0.002 S. One millisiemens is 0.001 siemens, so the numbers shrink as expected.
Drinking water, per cm: 0.5 mS in siemens
Drinking water, per cm comes to about 0.5 mS. Multiplying by the factor: 0.5 × 0.001 = 0.0005 S. Dividing the answer back by 0.001 returns the figure you started with, which is the quickest way to check you have the factor the right way up.
How to read your score
Frequently asked questions
How many siemens are in one millisiemens?
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 millisiemens to siemens?
siemens = millisiemens × 0.001. Reversed, millisiemens = siemens ÷ 0.001, which is the same as multiplying by 1000.
Which is the bigger unit, the millisiemens or the siemens?
The siemens. One millisiemens is only 0.001 of a siemens, so it takes 1000 millisiemens to make one siemens.
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 millisiemens?
One milli siemens is one thousandth of a siemens (1e-3 siemens).
What is a siemens?
The siemens is the reciprocal of the ohm: one siemens is one amp per volt.
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.
Millisiemens to siemens reference tables
| Millisiemens | Siemens |
|---|---|
| 0.5 mS | 0.0005 S |
| 1 mS | 0.001 S |
| 2 mS | 0.002 S |
| 3 mS | 0.003 S |
| 5 mS | 0.005 S |
| 10 mS | 0.01 S |
| 20 mS | 0.02 S |
| 25 mS | 0.025 S |
| 50 mS | 0.05 S |
| 75 mS | 0.075 S |
| 100 mS | 0.1 S |
| 250 mS | 0.25 S |
| 500 mS | 0.5 S |
| 1000 mS | 1 S |
| 5000 mS | 5 S |
Exact factor: 1 millisiemens = 0.001 siemens.
| Quantity | mS | S |
|---|---|---|
| Distilled water, per cm | 5.5e-05 mS | 5.5e-08 S |
| Drinking water, per cm | 0.5 mS | 0.0005 S |
| Hydroponic nutrient solution, per cm | 2 mS | 0.002 S |
| Sea water, per cm | 5000 mS | 5 S |
| 1 kohm resistor | 1 mS | 0.001 S |
| 10 ohm resistor | 100 mS | 0.1 S |
Published reference values, converted with the same factor this page uses.