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SMD Capacitor Code Calculator
SMD Capacitor Code Calculator
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Decoding surface-mount device (SMD) capacitor markings can be challenging, as different manufacturers utilize diverse coding systems across multi-layer ceramic (MLCC), tantalum, and aluminum electrolytic capacitors. This interactive SMD capacitor code calculator instantly translates 3- / 4-digit code, alphabetical code and EIA-198 code into precise capacitance values and tolerance percentages.
Whether you are reverse-engineering a high-density PCB, reworking an RF amplifier board, or sorting component reels for an SMT pick-and-place machine, automated code verification eliminates manual diagnostic errors.
Understanding SMD Capacitor Marking Systems
Unlike standard resistors, SMD capacitors vary significantly in how their values are displayed depending on their case size and dielectric material:
- The 3-Digit Code System: The most common layout. The first two digits represent the significant figures of the capacitance value in picofarads (pF), and the third digit is the multiplier — the number of zeros (ex.: code "103" indicates 10000 pF). Note: in most cases the third digit (multiplier) indicates the number of zeros, but some manufacturers use "8" for 0.01 and "9" for 0.1 multiplier. Please refer to manufacturer specifications. For capacitance <10 pF the capital letter "R" is used to indicate the position of a decimal point (ex.: codes "R50" or "0R5" indicate 0.5 pF). If 3- / 4-digit code starts with a capital letter (except "R"), it represents the maximum voltage. A capital letter at the end of the code represents capacitor tolerance. The most common industry codes are J (±5%), K (±10%), and M (±20%). For example, a capacitor marked 104K means it has a nominal capacitance of 100 nF with an allowable factory variance of ±10%, meaning its true in-circuit capacitance can safely rest between 90 nF and 110 nF.
- The 2-Digit / EIA-198 System: Typically found on ultra-small ceramic chip capacitors. It features a letter representing a specific two-digit value base, followed by a single number acting as the multiplier. For example, the letter "A" stands for 1.0, "N" stands for 3.3, and "S" stands for 4.7. If you see an SMD capacitor marked S2, it means 4.7 multiplied by 10² (100), resulting in a value of 470pF. This calculator automatically decodes these alphanumeric EIA strings.
- Electrolytic and Tantalum Banding: These components often include a direct voltage rating (e.g., 16V or 35V) alongside a 3-digit capacitance code and a visible stripe indicating the positive terminal (anode).
Quick Value Conversion Guide
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SMD Code
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Value in Picofarads (pF)
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Value in Nanofarads (nF)
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Value in Microfarads (μF)
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Common Application
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101
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100 pF
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0.1 nF
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0.0001 μF
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High-Frequency RF Filtering
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102
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1,000 pF
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1 nF
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0.001 μF
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Signal Decoupling
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103
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10,000 pF
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10 nF
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0.01 μF
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Timing Circuits / Op-Amps
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104
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100,000 pF
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100 nF
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0.1 μF
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Standard Power Rail Bypass
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105
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1,000,000 pF
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1,000 nF
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1 μF
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Bulk Low-Frequency Filtering
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To determine values of other SMD components use our SMD Resistor Code Calculator and SMD Inductor Code Calculator.
Frequently Asked Questions
How do I read a 3 digit SMD capacitor code?
To read a standard 3-digit SMD capacitor code, interpret the first two numbers as the base value in picofarads (pF) and the third number as the multiplier (10x). For instance, if the capacitor reads 223, you take 22 and multiply it by 10³ (or add three zeros), which equals 22,000pF. Converting this value yields 22 nF or 0.022 μF. If a lowercase "R" is present, it acts as a decimal point (e.g., 4R7 equals 4.7 pF).
Why are most ceramic SMD capacitors (MLCC) completely blank with no markings?
Multi-Layer Ceramic Capacitors (MLCCs) in standard case sizes like 0402, 0603, and 0805 are mass-produced without any surface markings due to physical space constraints and cost optimization. Because the ceramic manufacturing baking process alters the surface profile, printing legible ink or laser codes on millions of tiny components is impractical. To identify a blank SMD capacitor's value, you must desolder the component and measure it out-of-circuit using an LCR meter or a digital multimeter with a capacitance setting.
How do you identify the polarity of SMD tantalum vs electrolytic capacitors?
Unlike non-polarized MLCC ceramic chips, tantalum and aluminum electrolytic SMD capacitors are highly polarized and will fail catastrophically if installed backward.
- SMD Tantalum Capacitors: Feature a rectangular body where a solid colored stripe (often dark or white) marks the Positive (Anode) terminal.
- SMD Aluminum Electrolytic Capacitors: Feature a cylindrical metallic tin with a flat base, where a black filled-in wedge or stripe marks the Negative (Cathode) terminal.
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