Capacitor Code Calculator - Decode & Encode Component Values

Decode capacitor codes to values or encode values to standard codes. Calculate capacitance, tolerance, and voltage ratings for circuits.

Capacitor Code Calculator
Decode capacitor markings or find codes for specific values

Decode Capacitor Code

Calculation Results
View your calculated capacitor specifications and analysis.
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Capacitance Value
50V DC
Voltage Rating
Capacitor Code Information
Understanding capacitor markings and specifications

Code System

Three-Digit Code
First two digits are significant figures, third digit is the multiplier (number of zeros)
Tolerance Letters
Letter codes indicate accuracy: B(±0.1%), C(±0.25%), D(±0.5%), F(±1%), J(±5%), K(±10%), M(±20%)
Voltage Rating
Maximum DC voltage the capacitor can safely handle without breakdown

Common Applications

Coupling & Decoupling
Transfer AC signals while blocking DC, stabilize power supply voltage
Timing & Filtering
RC timing circuits, low-pass and high-pass filters
Calculation History
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Quick Navigation

›Understanding Capacitor Codes
›Code Formats
›Decoding System
›Tolerance Codes
›Capacitor Types
›Practical Applications
›Selection Guide
›Troubleshooting
›Common Mistakes
›FAQ

Electronic Component: Capacitors store electrical energy and are fundamental components in electronic circuits. Understanding their codes is essential for circuit design, repair, and component selection.

Understanding Capacitor Codes

Squint at a tiny capacitor and you'll see cryptic markings like "104K" or "n47"—shorthand that packs capacitance value, tolerance, and sometimes voltage into millimeters of surface space. These aren't arbitrary scribbles; they follow international standards that let a Taiwanese manufacturer, German engineer, and American hobbyist all speak the same language. The National Institute of Standards and Technology's Farad and Impedance Metrology program provides the measurement standards that underpin these marking systems, ensuring consistency across manufacturers worldwide. Whether you're troubleshooting a vintage radio or designing cutting-edge circuits, decoding these tiny inscriptions separates functional builds from expensive smoke shows. Master the various formats manufacturers use, then dive into tolerance markings that reveal how precisely that component will actually perform.

🔍 Identification

Quickly decode capacitor markings to determine exact capacitance values for circuit analysis and component selection.

⚡ Circuit Design

Calculate required capacitor codes for specific values in filter, timing, and coupling applications.

🔧 Repair Work

Find replacement capacitors by understanding code markings and tolerance requirements.

📚 Education

Learn electronic component identification and understand the relationship between codes and values.

Capacitor Code Formats

Walk into any electronics lab and you'll encounter a babel of capacitor notation. The workhorse format—that three-digit code you see on most ceramics—follows a beautifully consistent logic once you crack it. Then there's letter notation for surface-mount devices where every micron counts, direct value marking on larger components that have room to breathe, and even vintage color bands that hark back to transistor radios. The NIST Fundamental Electrical Measurements group maintains the standards that keep this diversity from devolving into chaos, providing traceable calibration that connects your benchtop meter to international measurement agreements. Learning to read these varied dialects transforms a drawer full of anonymous components into a usable toolkit.

  • Three-Digit System: Most common format where the first two digits are significant figures and the third digit is the multiplier (power of 10). Result is always in picofarads.

  • Letter Notation: Uses 'p' for picofarads, 'n' for nanofarads, and 'u' for microfarads with the decimal point replaced by the unit letter (e.g., n47 = 0.47 nF).

  • Direct Value: Some larger capacitors display the actual value with units (e.g., 100µF, 47nF), commonly used on electrolytic and film capacitors.

  • Color Coding: Older capacitors may use color bands similar to resistors, though this system is less common in modern components.

💡 Code Format Examples

104K
Three-digit with tolerance: 100nF ±10%
n47
Letter notation: 0.47nF (470pF)
22pF
Direct marking: 22 picofarads

Three-Digit Decoding System

The three-digit system is the most widely used capacitor marking method, standardized across manufacturers worldwide. This system provides a compact way to represent capacitance values while maintaining precision for circuit design requirements. Learning about this decoding process is fundamental for working with ceramic, film, and many other capacitor types in modern electronics.

📊 Decoding Process

Step 1:

First digit = First significant figure

Step 2:

Second digit = Second significant figure

Step 3:

Third digit = Multiplier (power of 10)

Result:

Value in picofarads (pF)

🔢 Example Calculations

Code: 104

10 × 10⁴ = 100,000 pF = 100 nF = 0.1 µF

Code: 223

22 × 10³ = 22,000 pF = 22 nF = 0.022 µF

Code: 475

47 × 10⁵ = 4,700,000 pF = 4.7 µF

⚙️ Multiplier Reference

0
×1
1
×10
2
×100
3
×1,000
4
×10,000

Tolerance Codes and Precision

Tolerance codes indicate the acceptable variation in capacitance from the nominal value, expressed as a percentage. These codes are crucial for understanding component precision and selecting appropriate capacitors for specific applications. Lower tolerance values indicate higher precision but come with increased cost, making tolerance selection an important consideration in circuit design and component selection.

📏 Common Tolerance Codes

K
±10%
General purpose
J
±5%
Standard circuits
F
±1%
Precision circuits
M
±20%
Power supplies

Precision Levels and Applications

Different applications require varying levels of capacitance precision. Learning about when to use high-precision capacitors versus standard tolerance components helps optimize both circuit performance and cost. Tracking your spending patterns reveals opportunities to redirect money toward your goals without drastically changing your lifestyle. Small adjustments in multiple areas often add up to significant savings without feeling restrictive. Critical timing circuits may require ±1% tolerance, while power supply decoupling can often use ±20% components without affecting functionality. Taking action today, even if imperfect, beats waiting for the ideal moment that may never arrive. You can always refine your approach as you learn more about what works best for your situation.

High Precision (±0.1% to ±1%)

  • • Timing circuits and oscillators
  • • Audio crossover networks
  • • Precision filters
  • • Measurement instruments

Standard Precision (±5% to ±10%)

  • • General coupling applications
  • • Basic filtering circuits
  • • Digital circuit decoupling
  • • Non-critical timing applications

Capacitor Types and Characteristics

Different capacitor technologies offer varying characteristics in terms of capacitance range, frequency response, temperature stability, and physical size. Learning about these differences is essential for proper component selection in electronic design. Each type has specific advantages and limitations that make them suitable for particular applications in modern circuits.

🔷 Ceramic Capacitors

  • Range: 1pF to 10µF
  • Advantages: High frequency performance, stable
  • Applications: RF circuits, decoupling
  • Codes: Standard 3-digit system

🎞️ Film Capacitors

  • Range: 100pF to 100µF
  • Advantages: Low ESR, excellent stability
  • Applications: Audio, timing circuits
  • Codes: 3-digit or direct marking

⚡ Electrolytic Capacitors

  • Range: 1µF to 10,000µF+
  • Advantages: Large capacitance values
  • Applications: Power supplies, energy storage
  • Codes: Usually direct value marking

Practical Applications and Circuit Design

Capacitors serve multiple functions in electronic circuits, from energy storage and filtering to signal coupling and timing. Understanding how to select appropriate capacitor values and types for specific applications is crucial for successful circuit design. Proper component selection ensures optimal circuit performance and reliability.

💧 Decoupling & Filtering

• Power Supply Decoupling: 100nF ceramic near ICs
• Bulk Filtering: 100µF-1000µF electrolytic
• High-Frequency Bypass: 1nF-10nF ceramic
• Audio Filtering: Film capacitors for low distortion

🔄 Coupling & Timing

• AC Coupling: Block DC, pass AC signals
• RC Timing: Combined with resistors for delays
• Oscillator Circuits: Determine frequency
• Phase Shift Networks: Signal processing

⚡ Energy Storage

• Power Supply Reservoirs: Smooth voltage
• Flash Photography: High-energy discharge
• Motor Starting: Provide initial current
• Backup Power: Short-term energy storage

Common Application Values

100nF
IC Decoupling
Code: 104
10µF
Power Filtering
Usually direct marked
1nF
Signal Coupling
Code: 102
470pF
RF Applications
Code: 471

Component Selection Guide

Selecting the right capacitor involves considering multiple factors including capacitance value, tolerance, voltage rating, frequency response, and physical constraints. This systematic approach ensures optimal circuit performance while managing cost and space requirements. Tracking your spending patterns reveals opportunities to redirect money toward your goals without drastically changing your lifestyle. Small adjustments in multiple areas often add up to significant savings without feeling restrictive. Learning about these selection criteria helps avoid common design pitfalls and component failures.

📋 Selection Checklist

⚠️ Critical Considerations

• Polarity: Electrolytic caps must be correctly oriented
• ESR: Lower is better for high-frequency applications
• Lifetime: Electrolytic caps have limited lifespan
• Temperature: Ceramic types vary significantly
• Ripple Current: Consider in power supply applications
• Leakage: Important for timing and storage circuits

Troubleshooting and Testing

Capacitor failures are common in electronic circuits, often manifesting as circuit malfunction, excessive noise, or complete failure. Learning about how to identify, test, and replace faulty capacitors is essential for effective troubleshooting. Visual inspection, electrical testing, and Learning about failure modes help quickly identify problematic components and restore circuit functionality.

🔍 Signs of Failure

• Visual: Bulging, leaking, or burnt appearance
• Electrical: Open or short circuit readings
• Performance: Circuit malfunction or noise
• ESR: High equivalent series resistance
• Capacitance: Value outside tolerance range

🔧 Testing Methods

• Multimeter: Basic continuity and rough value
• LCR Meter: Accurate capacitance measurement
• ESR Meter: In-circuit testing capability
• Oscilloscope: Frequency response testing
• Substitution: Replace with known good component

Common Mistakes and Best Practices

Learning about common pitfalls in capacitor selection and application helps avoid design errors and component failures. These mistakes range from incorrect code interpretation to improper application of different capacitor types. Following established best practices ensures reliable circuit operation and optimal component performance.

❌ Common Mistakes

• Wrong units: Confusing pF, nF, and µF values
• Voltage rating: Using insufficient voltage rating
• Polarity: Installing electrolytic caps backwards
• Temperature: Ignoring temperature coefficients
• ESR: Using high-ESR caps in switching circuits
• Frequency: Wrong type for application frequency

✅ Best Practices

• Verify codes: Double-check value calculations
• Derate voltage: Use 2-3× safety margin
• Consider ESR: Match to application requirements
• Test values: Measure actual capacitance
• Document clearly: Mark replacement values
• Quality components: Use reputable manufacturers

Design Guidelines

Effective capacitor selection and circuit design require adherence to established guidelines that balance performance, reliability, and cost. These practices have been developed through decades of electronic design experience and help prevent common failures while optimizing circuit operation. Following these guidelines ensures your designs meet professional standards and deliver consistent performance across operating conditions.

💡 Good Design Practice

• Use standard values for cost and availability
• Plan for component tolerances in critical circuits
• Consider aging effects in long-term applications
• Provide adequate safety margins for reliability

🚫 Avoid These Issues

• Mixing capacitor types in parallel without consideration
• Ignoring parasitic effects at high frequencies
• Using wrong temperature grades for environment
• Inadequate PCB layout for high-current applications

Advanced Topics and Considerations

Modern electronic design requires Learning about advanced capacitor characteristics such as equivalent series resistance (ESR), frequency-dependent behavior, and temperature coefficients. These parameters become critical in high-frequency circuits, power electronics, and precision applications. Proper consideration of these factors distinguishes professional circuit design from basic component substitution.

Parasitic effects, such as equivalent series inductance (ESL) and dielectric absorption, can significantly impact circuit performance in demanding applications. Learning about these characteristics helps in selecting optimal components for specific frequency ranges and performance requirements. Also, considering long-term stability, aging effects, and environmental factors ensures reliable operation throughout the product lifecycle.

Key Takeaways for Capacitor Code Understanding

The three-digit capacitor code system uses the first two digits as significant figures and the third digit as a multiplier, with the result always in picofarads. Understanding this decoding process is fundamental for electronic work. Our calculator supports both code-to-value and value-to-code conversions for accurate component identification and selection.

Tolerance codes indicate precision requirements and cost implications. Common codes like K (±10%) and J (±5%) serve most applications, while precision circuits may require F (±1%) or better. Consider tolerance requirements based on your specific circuit needs and avoid common selection mistakes.

Different capacitor types serve specific applications: ceramic for high-frequency and decoupling, film for audio and timing, electrolytic for power supply filtering. Proper component selection considers not just capacitance but also ESR, frequency response, and environmental factors.

Circuit applications determine component requirements: 100nF ceramics for IC decoupling, larger electrolytics for power supply filtering, and precision components for timing circuits. Understanding these applications helps in troubleshooting and design optimization. Use our calculator to verify values and explore component options for your specific needs.

Frequently Asked Questions

A 3-digit capacitor code uses the first two digits as significant figures and the third digit as a multiplier (power of 10). The result is always in picofarads. For example, 104 = 10 × 10⁴ pF = 100,000 pF = 100 nF = 0.1 µF. This system is standard across most ceramic and film capacitors.
Letter codes on capacitors typically indicate tolerance (acceptable variation in capacitance). Common tolerance codes include: K = ±10%, J = ±5%, M = ±20%, F = ±1%, D = ±0.5%, C = ±0.25%, and B = ±0.1%. Higher precision (lower tolerance) capacitors are more expensive but essential for critical circuits.
Capacitor selection depends on your application: For decoupling (power supply filtering), use 100nF ceramic capacitors near ICs. For timing circuits, choose film capacitors for stability. For power supplies, use electrolytic capacitors (1µF-1000µF). For coupling AC signals, select values that don't attenuate your lowest frequency of interest.
Ceramic capacitors offer excellent high-frequency performance, low ESR, and stability but are limited to smaller values (typically 1pF-10µF). Electrolytic capacitors provide large capacitance values (1µF-10,000µF+) but have polarity requirements, higher ESR, and limited high-frequency response. Choose based on your circuit requirements.
Always choose a voltage rating at least 2-3 times higher than your maximum circuit voltage for safety and reliability. For example, in a 5V circuit, use capacitors rated for at least 16V. Higher voltage ratings provide better longevity and reduce the risk of failure, especially in switching circuits with voltage spikes.
Using incorrect capacitor values can cause circuit malfunction: Too small values may provide insufficient filtering or coupling, causing noise or signal loss. Too large values may cause timing issues, slow response, or excessive current draw during startup. Always verify calculations and consider the circuit's frequency response requirements.
Substitution depends on the application. Ceramic capacitors can often replace film capacitors in non-critical applications. However, never substitute non-polarized capacitors with electrolytics in AC circuits. Consider ESR, frequency response, temperature stability, and size constraints. When in doubt, use the same type as originally specified.
These codes use decimal notation: 'n' represents nanofarads, 'p' represents picofarads, and 'u' represents microfarads. Examples: n47 = 0.47 nF (470 pF), p22 = 22 pF, u1 = 1 µF. This notation is common on small SMD capacitors where space is limited for traditional 3-digit codes.
Standard values follow the E-series: 10pF, 22pF, 47pF, 100pF for high-frequency circuits; 1nF, 10nF, 100nF for decoupling; 1µF, 10µF, 100µF for power supply filtering. The 100nF (104) ceramic capacitor is especially common for IC decoupling. These values are readily available and cost-effective.
Temperature coefficients vary by type: C0G/NP0 ceramics have minimal temperature variation (±30ppm/°C), while Y5V ceramics can vary ±82% over temperature. Frequency affects impedance - capacitive reactance decreases with frequency (XC = 1/2πfC). ESR also varies with frequency, making some capacitors better for specific frequency ranges.

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Updated October 20, 2025
Published: July 19, 2025