The difference between uF and mFD occurs just because of what they stand for. Technically ‘mFD’ represents ‘milli-Farad’ while ‘uF’ stands for ‘microFarad’ which is an order of magnitude smaller.
They are equivalent units of measurement in theory. But uF is far less. The value of a microfarad is 10˄-6 farads. Some older capacitor manufacturers labeled their products with “mF” instead of “uF.”

Key Differences Between uF and MFD Capacitors
Technically, mFD and uF are equivalent. However, one is more compact than the other. A microfarad is equivalent to 0.001mF, while a millifarad is 1000 uF. It is simpler to indicate the order of magnitude, to avoid having to write the value with a lot of zeroes in front of the Farad value.
Many manufacturers in the past have used mFD. However, the most popular unit today is the uF. Some people continue to use mFd because they are unable to locate the Greek symbol ‘µ’, which resembles the letter “u” on their keyboards.
What are mFD and uF in Capacitor
“uF” is a typographic substitute for µF, microfarad. “mF” is also a substitute for ‘milli-Farad’. “uF” is the marking used by manufacturers when they couldn’t print the Greek symbol to make the correct µF marking for microfarads.
Actually, uF (microfarads) is one-millionth of a farad whereas mF (milliFarads) is one-thousandths of a Farad. There’s a difference of 1000! A millifarad is 1000 microfarads.
What is the Meaning of MFD in Capacitor
MFD in the capacitor means microfarads which is a technical terminology used to describe the level of capacity in a capacitor. As the prefix suggests, one microfarad is equivalent to 1×10^-6 Farads. A standard capacitor may have an MFD ranging from 5 to 80 MFD.
Older capacitors were frequently designated as MFD due to equipment difficulties in printing the symbol ‘µ’ on the shell or other manufacturer-specific factors.
Again sometimes they made their capacitors with mF rather than uF. There is some ambiguity in this situation since mF can be mistaken for milliFarads rather than microfarad. That’s why it is way better to use MFD for indicating microfarads’ range of capacitance.
Are Capacitors Marked mFD or MFD Different than µF Caps
Many capacitors have the MFD or mFd label following the capacitance value. The most common marking on capacitors corresponds to the letter “µF”. Microfarad is indicated by the µF.
It was common practice for older capacitors to be marked as MFD or mFD either for machinery difficulty to produce the µ symbol print on the casing or for other manufacturer-specific reasons. An example of a capacitor that is still functional is given below-

Here the product label 250 MFD is for indicating the actual value of 250 microfarads or 250 µF, not millifarad.
How many uF are in an MFD
It is assumed that you are converting between microfarads, as MFD stands for microfarads which is expressed in the Greek symbol µF. So the term MFD ratings are similar to uF.
The farad is the capacitance unit derived from the SI. 1000000 uF, often known as 1000000 microfarads, is one farad.
How much uF is in an MFD Capacitor
As we know, mFD stands for “milli-Farad,” whereas µF stands for “micro-Farad”, according to conversion convention, One millifarad contains 1000 microfarads. By this, you may convert between millifarads and microfarads.
You can convert uF to mFD to decide whether or not the gadget is suitable for you if you are familiar with the relationship between millifarads and microfarads. Let’s see some calculations to convert mFD to uF!
mFD | uF |
10 | 10,000 |
100 | 100,000 |
500 | 500,000 |
What does a higher MFD capacitor mean?
The electrical current goes more quickly the higher the voltage rating of your capacitor. The microfarad (MFD) rating is the second rating. The capacity of a capacitor is measured in microfarads. According to the amount of electrical current a device can store depends on its microfarad rating.
Conclusion
Both the terms “uF” and “mFD” may be used for similar measurement scales where uF stands for micro-Farad (MFD) which is expressed mainly by the Greek symbol ‘µF’. Again for mFd, it indicates milli-Farad ranges. A difference of a factor of 1000.
I am fully satisfied to your answer..Thank you.
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So if the original installed capacitor states 135-162MFD and the replacement states 135-162 mFD (mew) that means they are the same…?
“mFD” is an unconventional way of representing microfarads. Both “MFD” and “mFD” would indicate microfarads, which is a common unit for specifying capacitance values. So, yes, it’s reasonable to assume that they are the same.
So many knowledge has gained. Lot of thanks.
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