Capacitor Code Calculator

Decode ceramic, SMD, tantalum, and electrolytic capacitor markings. Includes 3‑digit/4‑digit EIA codes, tolerance letters, voltage codes, temperature coefficients, package size impact, and manufacturer-specific references. Trusted by professional engineers and educators.

? 104 (100nF)
? 472K (4.7nF ±10%)
⚡ 225 (2.2µF)
?️ 1002 (10nF)
? 4R7J + 2A (4.7pF ±5% / 100V)
? 105M + 1H (1µF ±20% / 50V)
? 1R2B (1.2pF ±0.1pF)
Local computation only Supports 3/4-digit codes, 'R' decimal notation (4R7 = 4.7pF) – All decoding happens in your browser. No data is uploaded or stored.

Understanding Capacitor Codes: Professional Reference

Capacitors often use abbreviated alphanumeric codes to indicate capacitance, tolerance, and voltage rating. The EIA‑198 standard defines the widely adopted 3‑digit and 4‑digit code system. This calculator decodes these markings instantly, converting them into practical engineering units (picofarads, nanofarads, microfarads) and providing tolerance/voltage interpretation. All algorithms follow strict multiplier rules (multiplier range 0–8). Codes with multiplier 9 are invalid per EIA‑198 and will trigger a warning.

How 3-Digit Codes Work

For a 3‑digit code: AB C → Capacitance (pF) = (AB) × 10C
Example: 104 → 10 × 104 = 100,000 pF = 100 nF = 0.1 µF.

For values below 10 pF, the letter 'R' indicates a decimal point: 4R7 = 4.7 pF. 4‑digit codes use three significant digits: 2202 → 220 × 102 = 22,000 pF = 22 nF. Multiplier restriction: Only multipliers 0 through 8 are allowed. A code like 109 (multiplier 9) is non‑standard and will be rejected.

Professional Decoding Examples

Marking Decoded Capacitance Alternative Units Special Note
1R2 1.2 pF 0.0012 nF Decimal R notation
680 68 pF 0.068 nF Multiplier 0
229 ⚠️ Invalid (multiplier 9) — Not EIA‑198 compliant
1003 100,000 pF = 0.1 µF 100 nF 4-digit code (100 × 10³)
0R5 0.5 pF 0.0005 nF Sub-picofarad

Temperature Coefficients & Their Impact on Circuit Design

Capacitor dielectrics drastically affect capacitance stability over temperature. The EIA Class I (C0G/NP0) and Class II (X7R, X5R, Y5V) define how capacitance changes. Using the wrong dielectric can cause timing drift, filter detuning, or power supply instability.

Common Dielectrics & Temp. Stability
Code ΔC over temp range Typical application
C0G / NP0 ±30 ppm/°C (near-zero) Oscillators, RF, timing circuits
X7R ±15% (-55°C to +125°C) Decoupling, general purpose
X5R ±15% (-55°C to +85°C) Consumer electronics, battery-powered
Y5V +22% / -82% (-30°C to +85°C) Low-cost, non-critical filtering
Design Guidelines
  • For precision RC oscillators, always use C0G/NP0 – X7R can shift frequency by >10% over temperature.
  • In SMPS output filters, X7R or X5R is acceptable; Y5V causes severe capacitance drop at high temp (up to 80% loss).
  • DC bias effect: Class II capacitors lose capacitance under applied DC voltage. A 10V X7R rated 1µF may drop to 0.3µF at 10V. Derate by 50% voltage margin.

Package Size vs. Voltage & Capacitance Rating

For surface-mount ceramic capacitors (MLCC), the physical size (EIA case code) directly limits maximum voltage and capacitance. The table below shows typical relationships.

Case Size (inch/mm) Typical max capacitance @ 50V Typical max voltage @ 1µF Common applications
0402 (1.0×0.5mm) 0.1µF 50V Mobile devices, dense PCBs
0603 (1.6×0.8mm) 1µF 50V General purpose, decoupling
0805 (2.0×1.25mm) 4.7µF 100V Power supplies, industrial
1206 (3.2×1.6mm) 22µF 200V High voltage, bulk filtering
1210 (3.2×2.5mm) 47µF 100V High capacitance needs

Pro tip: Higher voltage ratings in the same package size usually reduce maximum capacitance. Always check manufacturer derating curves.

Manufacturer-Specific Codes & Tantalum Capacitor Encoding

Beyond standard EIA codes, many vendors add proprietary markings for series, date codes, or special characteristics. Below is a quick reference for common manufacturer-specific codes.

Manufacturer Code example Meaning Notes
Murata GRM / GCM series Ceramic general / automotive Often printed with capacitance code only
KEMET C0402C104K5R Case, capacitance, tolerance, voltage, dielectric Systematic ordering code
AVX TAJA104K025 Series, case, value, tolerance, voltage Tantalum specific
TDK CGA (automotive) / C series Flexible termination Markings may include lot traceability
Panasonic ECJ / ECE General / electrolytic Voltage often marked separately

Tantalum Capacitor Special Encoding

Solid tantalum capacitors (SMD) use a different marking scheme: typically a colored band or alphanumeric code indicating capacitance, voltage, and polarity. Common format: case size + capacitance code + voltage code. Example: A104K → Case A (3216), 0.1µF, K=±10%. Voltage often given by a separate letter: G=4V, J=6.3V, A=10V, C=16V, D=20V, E=25V, V=35V, T=50V (AVX/KEMET standard). Polarity is marked with a stripe or bevel. Our calculator decodes the numeric part; use the voltage code table for tantalum as well.

Tantalum Caution: Reverse polarity or excessive ripple current can cause catastrophic failure. Always observe polarity marking (stripe = positive for tantalum, opposite of aluminum electrolytic). Voltage derating to 50% of rating is recommended for high-reliability designs.

Real‑World Applications & Engineering Relevance

Case Study: Power Supply Filter Capacitor Failure

A switching power supply repair reveals a bulged capacitor marked "225M 2E". Using the calculator: 225 → 2.2 µF, tolerance M = ±20%, voltage code 2E = 250V. The replacement must meet at least 250V rating and 2.2 µF. This quick decode prevents incorrect substitution and ensures circuit safety.

Field Failure Analysis Example

In an automotive ECU, a ceramic capacitor marked "104Z" was found cracked. Decoding: 104 = 100 nF, tolerance Z = +80%/-20% (general purpose). Replacement with a 100 nF X7R (tighter tolerance) resolved intermittent signal glitches. The calculator helped identify the original loose tolerance, guiding a better upgrade.

Beyond Basic Codes: Temperature Coefficients & Dielectrics

High-reliability circuits also use EIA Class II dielectrics (X7R, X5R, Y5V, C0G/NP0). While not directly decoded here, the capacitance code often appears alongside such markings. For example, "104 X7R" indicates 100 nF with X7R dielectric (±15% over -55°C to +125°C). X7R is preferred for decoupling, while C0G (NP0) offers near-zero drift for timing circuits. Our calculator provides the first critical step; always verify dielectric class from the full marking.

Pro Tip: When you see a code like "473 X7R 1H", the calculator gives 47 nF, tolerance (if any), and voltage 50V. The X7R tells you the temperature stability – essential for automotive or industrial designs.

Step‑by‑Step Guide to Using This Tool

  1. Enter the capacitor marking (e.g., "104", "472K", "1002") into the Capacitor Code field. Optionally select a tolerance or voltage code if not included in the marking.
  2. Click "Decode" – the tool immediately calculates capacitance in pF, nF, and µF.
  3. View the tolerance percentage and voltage rating (if provided). The explanation field shows the mathematical decoding.
  4. Use example buttons to explore typical values, or clear the form for a new entry.

Limitations & Advanced Markings

This calculator focuses on standard EIA‑198 numeric codes. It does not decode:

  • Two‑digit codes with ambiguous meaning (e.g., "10" could be 10 pF or a date code). Always verify with a multimeter if uncertain.
  • Military standard markings (MIL‑PRF‑39014) that use color bands or different letter codes.
  • Direct markings like "10n" or "2.2µ" – those are self‑explanatory but not parsed; use the numeric code equivalent (e.g., 103 for 10 nF).
  • Non‑EIA voltage codes from Japanese manufacturers (e.g., "0J" is included, but some use "A" for 10V, which is already covered).

If your capacitor marking does not match the expected format, consult the manufacturer's datasheet.

Verification Table: Sample Code Conversions

Marking Decoded Capacitance Alternative Units Tolerance (if any)
101 100 pF 0.1 nF —
222 2200 pF 2.2 nF —
473K 47000 pF 47 nF / 0.047 µF ±10%
105 1,000,000 pF 1 µF —
1004 1,000,000 pF 1 µF (4‑digit) —
3R3 3.3 pF 0.0033 nF —
225M 2,200,000 pF 2.2 µF ±20%
Pro Tips: Avoiding Common Misinterpretations
  • Never confuse a capacitor code like “104” (100nF) with “1004” (1µF). The extra digit changes magnitude.
  • Codes starting with '0' (e.g., "010") decode as 1 pF (01 × 10⁰ = 1 pF), not 10 pF. Our parser follows EIA rules correctly.
  • Some capacitors omit tolerance letters – always verify with a datasheet if precision is critical.
  • Multiplier 9 is invalid. If you see "109", it likely means 1.0 pF with a misprint or non‑standard marking. Use a multimeter to confirm.
  • For SMD tantalum capacitors, the voltage code may be followed by a polarity indicator; our voltage table covers standard EIA codes used for tantalum as well.

Frequently Asked Questions (Advanced)

'R' indicates a decimal point for values below 10 pF. Example: 4R7 = 4.7 pF; 0R5 = 0.5 pF.

Yes. Most SMD ceramic capacitors use the same 3‑digit/4‑digit EIA code. Our calculator handles them perfectly. For tantalum capacitors, additional voltage codes are also supported via the voltage dropdown.

Engineers use pF, nF, and µF depending on scale. The tool provides all three to eliminate conversion errors during design or repair.

Very small value capacitors sometimes use two digits (e.g., "10" = 10 pF). Our decoder interprets 2‑digit codes as direct picofarads, though most industry codes are 3+ digits. Be cautious: some 2-digit codes may be date codes.

Per EIA‑198, the multiplier digit can only be 0 through 8. A multiplier of 9 is reserved for special test conditions or is invalid. The calculator will show a warning if you enter a code like "109" or "1009".

Mostly yes. The EIA voltage code (e.g., 1H = 50V) is standard across both types. However, some tantalum manufacturers use additional codes for surge voltage. Our table includes the most common ratings.

Tantalum SMD capacitors typically have a colored (yellow, black, or orange) rectangular body with a stripe indicating positive terminal. Aluminum electrolytic SMD capacitors have a silver can with a black stripe marking negative. Tantalum codes often include case size letter (A, B, C, D, E) followed by capacitance and voltage. Aluminum electrolytics usually have printed voltage and capacitance directly (e.g., 100µF 16V).

For high-reliability applications (aerospace, medical, automotive), derate tantalum capacitors to 50% of the rated voltage. For general commercial use, 70-80% derating is common. Never exceed rated voltage – tantalums are sensitive to overvoltage and can catch fire. Always use series resistance to limit inrush current.
Based on EIA‑198‑1‑F (2020), IEC 60062, and manufacturer application notes from KEMET, AVX, Murata, TDK, and Vishay. Temperature coefficient data derived from EIA RS-198. Updated April 2026 by GetZenQuery Tech team.
Further reading: Electronics Tutorials - Capacitor Code | Vishay Capacitor Marking Guide | Murata Capacitor Guide | KEMET Tantalum Handbook