How to Read Capacitor Value? . Understanding capacitor values is a fundamental skill for anyone working with electronics. Capacitors, a vital component in electronic circuits, store and release electrical energy, ensuring devices function smoothly. Accurately reading their values is essential for repairs, designs, and troubleshooting. This guide will take you through every step to confidently read capacitor values, from markings to measurement techniques.
Unlike resistors, capacitors use a wide variety of codes to describe their characteristics. Physically small capacitors are especially difficult to read, due to the limited space available for printing. The information in this article should help you read almost all modern consumer capacitors. Don’t be surprised if your information is printed in a different order than the one described here, or if voltage and tolerance info is missing from your capacitor. For many low-voltage DIY circuits, the only information you need is the capacitance.
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What is a Capacitor?
A capacitor is an electrical component that stores and releases energy in a circuit. It consists of two conductive plates separated by an insulating material (dielectric). Capacitors come in various types, including:
- Ceramic Capacitors: Small, inexpensive, used in high-frequency applications.
- Electrolytic Capacitors: Higher capacitance, polarized, ideal for power supply circuits.
- Film Capacitors: Non-polarized, reliable in AC applications.
- Tantalum Capacitors: Compact, stable, often used in military and medical electronics.
Capacitors are measured in farads (F), with common units being microfarads (µF), nanofarads (nF), and picofarads (pF).
Capacitor Standard Codes
Generally, the values of capacitance, voltage rating, tolerance and even the polarity (in case of polarized capacitor) are printed on the large size capacitor. On the other hand, for small capacitors like mica and ceramic capacitors, color codes are used to indicate their values (generally) in pF (picofarad).
The value of ceramic disk capacitors lower than 1000pf is printed on it in the form of digits and numbers. For example, the only number “300” is printed on a capacitor of 300pf.
Those capacitors having capacitance of 1000pf or more, their values can be read by the 3 digits numbers (e.g. 102. 103, 105 etc.) printed on it. These 3 digits color coding can be read as follows.
- 102 = 10 x 102 = 1000 pF (picofarad)
- 103 = 10 x 103 = 10,000 pF (picofarad)
- 105 = 10 x 105 = 1,000,000. pF (picofarad) = 1 μF (microfarad)
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How to Read Capacitor Value?
STEP 1
Understand the units of measurement used for capacitors. The base unit of capacitance is the Farad (F). This value is too large to be of use in a circuit. Smaller denominations of capacitance are used by electronic circuits.
- Read uF as microFarad. 1 microFarad is 1 times 10 to the -6 power Farad.
- Read pF as picoFarad. 1 picoFarad is 1 times 10 to the -12 power Farad.
STEP 2
Read the value directly on larger bodied capacitors. If the surface of the body is large enough, the value will be printed directly on the capacitor. For example, 47 uF indicates 47 microFarads.
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STEP 3
Read the capacitance of smaller bodied capacitors as two or three numbers. The designators uF or pF will not appear due to the small size of the capacitor body.
- Read two digit numbers as being in picoFarads (pF). For example, 47 would be read as 47 pF.
- Read three digit numbers as a base capacitance value in picoFarads and a multiplier. The first two digits will indicate the base capacitor value in picoFarads. The third digit will indicate a multiplier to be used on the base number to find the actual value of the capacitor.
- Use a third digit of 0 through 5 to place the corresponding number of 0s behind the base value. A third digit of 8 means multiply the base value by .01. A third digit of 9 means to multiply the base value by 0.1. For example, 472 would indicate a 4700 pF capacitor and 479 would indicate a 4.7 pF capacitor.
- Digit-Character-Digit. Some small capacitors are marked with codes like 1n0. The digits are the values before and after the decimal point and the the character tells you the dimension; so the example given is 1.0 nF (nano-Farad).
STEP 4
Look for a letter code. Some capacitors are defined by a three number code followed by a letter. This letter represents the tolerance of the capacitor, meaning how close the actual value of the capacitor can be expected to be to the indicated value of the capacitor. The tolerances are indicated as follows.
- Read B as 0.10 percent.
- Read C as 0.25 percent.
- Read D as 0.5 percent.
- Read E as 0.5 percent. This is a duplication of a D code.
- Read F as 1 percent.
- Read G as 2 percent.
- Read H as 3 percent.
- Read J as 5 percent.
- Read K as 10 percent.
- Read M as 20 percent.
- Read N as 0.05 percent.
- Read P as plus 100 percent to minus 0 percent.
- Read Z as plus 80 percent to minus 20 percent.
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ELECTROLYTIC CAPACITOR
An electrolytic capacitor is a polarized capacitor which uses an electrolyte to achieve a larger capacitance than other capacitor types.
In the case of through-hole capacitors, the capacitance value as well as the maximum rated voltage is printed on the enclosure. A capacitor that has “4.7μF 25V“ printed on it has a nominal capacitance value of 4.7μF and a maximum voltage rating of 25 volts, which is never to be exceeded.
In the case of SMD (surface mounted) electrolytic capacitors, there are two basic marking types. The first one clearly states the value in microfarads and the operating voltage. For example, using this approach, a 4.7 μF capacitor with an operating voltage of 25 volts would bear the marking “4.7 25V”. In the other marking system, a letter is followed by three numbers. The letter represents the voltage rating according to the table below. The first two numbers represent the value in picofarads, while the third number is the number of zeroes to be added to the first two. For example, a 4.7 μF capacitor with a voltage rating of 25 volts would bear the marking E476. This translates to 47000000 pF = 47000 nF = 47 μF.
| Letter | Voltage |
| e | 2.5 |
| G | 4 |
| J | 6.3 |
| A | 10 |
| C | 16 |
| D | 20 |
| E | 25 |
| V | 35 |
| H | 50 |
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Value of Standard Capacitor Codes
The following table shows the standard value of standard capacitor codes and letters markings printed on it.
| Code | Microfarad “μF” | Nanofarad “nF” | Picofarad “pF” | Code | Microfarad “μF” | Nanofarad “nF” | Picofarad “pF” |
| 100 | 0.00001 | 0.01 | 10 | 225 | 2.2 | 2200 | 2200000 |
| 101 | 0.0001 | 0.1 | 100 | 254 | 0.2 | 200 | 200000 |
| 102 | 0.001 | 1.0 | 1000 | 330 | 0.000033 | 0.033 | 33 |
| 103 | 0.01 | 10 | 10000 | 331 | 0.00033 | 0.33 | 330 |
| 104 | 0.1 | 100 | 100000 | 332 | 0.0033 | 3.3 | 3300 |
| 105 | 1.0 | 1000 | 1000000 | 333 | 0.033 | 33 | 33000 |
| 121 | 0.00012 | 0.12 | 120 | 334 | 0.33 | 330 | 330000 |
| 131 | 0.00013 | 0.13 | 130 | 335 | 3.3 | 3300 | 3300000 |
| 150 | 0.000015 | 0.015 | 15 | 470 | 0.000047 | 0.047 | 47 |
| 151 | 0.00015 | 0.15 | 150 | 471 | 0.00047 | 0.47 | 470 |
| 152 | 0.0015 | 1.5 | 1500 | 472 | 0.0047 | 4.7 | 4700 |
| 153 | 0.015 | 15 | 15000 | 473 | 0.047 | 47 | 47000 |
| 154 | 0.15 | 150 | 150000 | 474 | 0.47 | 470 | 470000 |
| 155 | 1.5 | 1500 | 1500000 | 502 | 0.005 | 5.0 | 5000 |
| 181 | 0.00018 | 0.18 | 180 | 561 | 0.00056 | 0.56 | 560 |
| 202 | 0.002 | 2.0 | 2000 | 562 | 0.0056 | 5.6 | 5600 |
| 205 | 2.0 | 2000 | 2000000 | 681 | 0.00068 | 0.68 | 680 |
| 220 | 0.000022 | 0.022 | 22 | 682 | 0.0068 | 6.8 | 6800 |
| 221 | 0.00022 | 0.22 | 220 | 683 | 0.068 | 68 | 68000 |
| 222 | 0.0022 | 2.2 | 2200 | 684 | 0.68 | 680 | 680000 |
| 223 | 0.022 | 22 | 22000 | 751 | 0.00075 | 0.75 | 750 |
| 224 | 0.22 | 220 | 220000 | 821 | 0.00082 | 0.82 | 820 |
Reading Large Capacitors
Know the units of measurement. The base unit of capacitance is the farad (F). This value is much too large for ordinary circuits, so household capacitors are labeled with one of the following units:
- 1 µF, uF, or mF = 1 microfarad = 10-6 farads. (Careful — in other contexts, mF is the official abbreviation for millifarads, or 10-3 farads.)
- 1 nF = 1 nanofarad = 10-9 farads.
- 1 pF, mmF, or uuF = 1 picofarad = 1 micromicrofarad = 10-12 farads.
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Read the capacitance value. Most large capacitors have a capacitance value written on the side. Slight variations are common, so look for the value that most closely matches the units above. You may need to adjust for the following:
- Ignore capital letters in the units. For example, “MF” is just a variation on “mf.” (It is definitely not a megafarad, even though this is the official SI abbreviation.)
- Don’t get thrown by “fd.” This is just another abbreviation for farad. For example, “mmfd” is the same as “mmf.”
- Beware single-letter markings such as “475m,” usually found on smaller capacitors. See below for instructions.
Look for a tolerance value. Some capacitors list a tolerance, or the maximum expected range in capacitance compared to its listed value. This isn’t important in all circuits, but you may need to pay attention to this if you require a precise capacitor value. For example, a capacitor labeled “6000uF +50%/-70%” could actually have a capacitance as high as 6000uF + (6000 * 0.5) = 9000uF, or as low as 6000 uF – (6000uF * 0.7) = 1800uF.
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Check the voltage rating. If there is room on the body of the capacitor, the manufacturer usually lists voltage as a number followed by a V, VDC, VDCW, or WV (for “Working Voltage”). This is the maximum voltage the capacitor is designed to handle.
- 1 kV = 1,000 volts.
- See below if you suspect your capacitor uses a code for voltage (a single letter or one digit and one letter). If there is no symbol at all, reserve the cap for low-voltage circuits only.
- If you are building an AC circuit, look for a capacitor rated specifically for VAC. Do not use a DC capacitor unless you have an in-depth knowledge of how to convert the voltage rating, and how to use that type of capacitor safely in AC applications.
Look for a + or – sign. If you see one of these next to a terminal, the capacitor is polarized. Make sure to connect the capacitor’s + end to the positive side of the circuit, or the capacitor could eventually cause a short or even explode. If there is no + or -, you can orient the capacitor either way.
- Some capacitors use a colored bar or a ring-shaped depression to show polarity. Traditionally, this mark designates the – end on an aluminum electrolytic capacitor (which are usually shaped like tin cans). On tantalum electrolytic capacitors (which are very small), this mark designates the + end. (Disregard the bar if it contradicts a + or – sign, or if it is on a non-electrolytic capacitor.)
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How to Read Capacitor Color Codes?
Except marking and alphanumeric codes, different color codes are also used to identify the value of a capacitor. These colored bands (on ceramic tubular capacitors) or dots ( on Mica capacitors) are printed on the outer surface of the capacitor.
Capacitance of Capacitor Color Code
The value of a capacitor having five color bands (or 5 dots) can be read using the following table.
In the following tables, the first three color bands show the value of capacitance, the fourth band as tolerance in percentage and the fifth band shows the temperature coefficient. For example:
- 1st Color Band = First Number of Value of Capacitor.
- 2nd Color Band = Second Number of value of Capacitor.
- 33rd Color Band = The number of Zeros (as multiplier) with the first two digits of capacitor (In numbers).
- 4th Color Band = Tolerance in percentage.
- 5th Color Band = Temperature coefficient.
Table for 5 bands color codes for ceramic capacitors
| Band Color | 1st Digit | 2nd Digit | Multiplier | Tolerance (%) | Temperature Coefficient | |
| Above 10pf | Below 10pf | |||||
| BLACK | 0 | 0 | 1 | ± 20% | ± 2.0pF | 0 |
| BROWN | 1 | 1 | 10 | ± 1% | ± 0.1pF | -30 |
| RED | 2 | 2 | 100 | ± 2% | ± 0.25pF | -80 |
| ORANGE | 3 | 3 | 1,000 | ± 3% | – | -150 |
| YELLOW | 4 | 4 | 10,000 | ± 4% | – | -220 |
| GREEN | 5 | 5 | 100,000 | ± 5% | ± 0.5pF | -330 |
| BLUE | 6 | 6 | 1,000,000 | ± 6% | – | -470 |
| VIOLET | 7 | 7 | – | ± 7% | – | -750 |
| GREY | 8 | 8 | 0.01 | +80%,-20% | ± 0.25pF | +30 |
| WHITE | 9 | 9 | 0.1 | ± 10% | ± 1.0pF | +120-750 |
| GOLD | – | – | 0.1 | ± 5% | – | – |
| SILVER | – | – | 0.01 | ± 10% | – | – |
Table for 4 bands color codes for ceramic & tubular paper capacitors with voltage rating (especially for dot color code for mica and molded paper capacitors).
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| Band Color | Significant Figure | Decimal Multiplier | Tolerances (%) | Voltage Rating |
| BLACK | 0 | 1 | – | – |
| BROWN | 1 | 10 | 1 | 100 |
| RED | 2 | 100 | 2 | 200 |
| ORANGE | 3 | 1,000 | 3* | 300 |
| YELLOW | 4 | 10,000 | 4* | 400 |
| GREEN | 5 | 100,000 | 5 | 500 |
| BLUE | 6 | 1,000,000 | 6 | 600 |
| VIOLET | 7 | 10,000,000 | 7 | 700 |
| GREY | 8 | 100,000,000 | 8 | 800 |
| WHITE | 9 | 1000,000,000 | 9 | 900 |
| GOLD | – | 0.1 | 5 | 1000 |
| SILVER | – | 0.01 | 10 | 2000 |
| No Color | – | – | 20 | 500 |
* Voltage Rating for K type Capacitors
** Multiply by 10 for tubular paper capacitors.
Voltage of Capacitor Color Code
| Band Color | Type “J” | Type “K” | Type “L” | Type “M” | Type “N” |
| BLACK | 4 | 100 | – | 10 | 10 |
| BROWN | 6 | 200 | 100 | 1.6 | – |
| RED | 10 | 300 | 250 | 4 | 35 |
| ORANGE | 15 | 400 | – | 40 | – |
| YELLOW | 20 | 500 | 400 | 6.3 | 6 |
| GREEN | 25 | 600 | 16 | 15 | |
| BLUE | 35 | 700 | 630 | – | 20 |
| VIOLET | 50 | 800 | – | – | – |
| GREY | – | 900 | – | 25 | 25 |
| WHITE | 3 | 1000 | – | 2.5 | 3 |
| GOLD | – | 2000 | – | – | – |
| SILVER | – | – | – | – | – |
Note: The letters of “J”, “K”, “L”, “M” & “N” shows the following types of capacitors
- Type “J” = Dipped Tantalum Capacitors
- Type “K” = Mica Capacitors
- Type “L” = Polyester & Polystyrene Capacitors
- Type “M” = Electrolytic Four-Bands Capacitors
- Type “N” = Electrolytic Three-Bands Capacitors
The following fig shows how to read the bumblebee capacigor color codes with a solved example of 0.047µF (equivalent to 47000 pF or 47 nF).
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FAQs about Reading Capacitor Values
1. How do I read a capacitor with no markings?
Use a multimeter in capacitance mode to measure its value.
2. What does the letter “K” mean on a capacitor?
It indicates tolerance, with “K” representing ±10%.
3. How do I convert pF to µF?
Divide the value in pF by 1,000,000. Example: 1,000,000 pF = 1 µF.
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