A capacitor sizes chart maps physical package dimensions to the maximum achievable capacitance and voltage ratings for a given dielectric material. For surface-mount devices (SMD), the Electronic Industries Alliance (EIA) standardizes these packages (e.g., 0805, 1206), while through-hole radial capacitors follow metric diameter and lead-pitch standards. If you need a 10µF bypass capacitor, this chart tells you whether it will fit in a compact 0805 footprint or if you must step up to a 1210 package, switch dielectrics, or use a radial electrolytic.
This reference provides the exact dimensional limits, standard capacitance ceilings, and the critical derating rules that dictate real-world performance on your workbench.
How to Read the Capacitor Sizes Chart
Before selecting a footprint, you must understand the columns in the chart below. The physical size of a capacitor is strictly limited by the dielectric material inside it.
- EIA Package Code: The standard imperial 4-digit code (e.g., 0805 means 0.08 by 0.05 inches). We also include the metric equivalent (e.g., 2012 means 2.0 by 1.2 mm) to prevent procurement errors, as a 0603 imperial is a 1608 metric.
- Dimensions (L x W x H): Maximum physical footprint in millimeters. Height (H) is often variable but critical for low-profile enclosures.
- Max Cap (X7R, 16V-50V): The ceiling for Class II temperature-stable ceramics at moderate voltages. Use this column for general decoupling and filtering.
- Max Cap (X5R, 6.3V-10V): The ceiling for lower-voltage, higher-density ceramics. Use this column for 3.3V and 5V logic rail bulk decoupling.
- Radial Equivalent: The standard through-hole aluminum electrolytic or film can size that provides the same or higher capacitance when SMD limits are reached.
The Master Capacitor Sizes Chart (EIA & Radial Standards)
Data sourced from EIA RS-384 standard for SMD chip dimensions and manufacturer datasheets from Kemet and Murata for dielectric limits at 25°C ambient.
| EIA Code (Imp.) | Metric Code | Dimensions (L x W mm) | Max Cap X7R (16-50V) | Max Cap X5R (6.3-10V) | Radial / Polymer Equivalent |
|---|---|---|---|---|---|
| 0201 | 0603 | 0.60 x 0.30 | 0.01µF | 0.1µF | N/A (Too small) |
| 0402 | 1005 | 1.00 x 0.50 | 0.1µF | 1.0µF | N/A |
| 0603 | 1608 | 1.60 x 0.80 | 0.47µF | 4.7µF | 4x5mm Radial |
| 0805 | 2012 | 2.00 x 1.25 | 2.2µF | 10µF | 5x7mm Radial |
| 1206 | 3216 | 3.20 x 1.60 | 10µF | 47µF | 6.3x7mm Radial |
| 1210 | 3225 | 3.20 x 2.50 | 22µF | 100µF | 8x10mm Radial |
| 1812 | 4532 | 4.50 x 3.20 | 47µF | N/A (Rare in X5R) | 10x12mm Radial |
| 2220 | 5650 | 5.60 x 5.00 | 100µF | N/A | 12.5x16mm Radial |
For authoritative standard references on capacitor package sizing and dielectric classifications, consult the Kemet Technical Guides or the SparkFun Capacitor Tutorial.
Derating Rules: How DC Bias Modifies Base Values
The chart above lists nominal, zero-bias capacitance. In practice, Class II ceramic dielectrics (X5R, X7R, Y5V) suffer from severe DC bias derating. As you apply DC voltage across the capacitor, the dielectric's permittivity drops, effectively shrinking the capacitance.
Worked Example: You need a 10µF bypass capacitor for a 5V buck converter output. You select a 10µF, 6.3V, X5R 0805 capacitor because it fits your board space. However, at 5V DC bias (roughly 80% of its rated voltage), that 10µF capacitor will derate to approximately 3.5µF to 4.5µF effective capacitance.
How to apply derating rows to your pick:
- Rule of Thumb: Expect a 40% to 70% loss in capacitance for X5R/X7R parts operated near their rated voltage.
- The Fix: Always double the voltage rating. If your rail is 5V, use a 10V or 16V rated capacitor. A 10µF, 16V 0805 will retain roughly 8.5µF at 5V bias.
- Size Penalty: If a higher voltage rating pushes you out of the 0805 footprint (e.g., 22µF at 16V requires a 1210), you must either increase the PCB footprint or place two 10µF 0805 capacitors in parallel.
Decision Tree: Picking Your Exact Package
Use this decision path to terminate your selection process with a concrete BOM pick. Assume standard FR4 PCB, 25°C ambient, and automated pick-and-place assembly.
| Your Requirement | Decision Path | Concrete Pick (Default Recommendation) |
|---|---|---|
| Need < 1µF for high-frequency IC decoupling (100MHz+) | Keep footprint minimal to reduce parasitic inductance (ESL). | 0402 (1005) X7R, 16V. (e.g., 0.1µF) |
| Need 1µF to 4.7µF for general 3.3V/5V rail bulk decoupling | Balance board space with DC bias headroom. Use 10V rating. | 0603 (1608) X5R, 10V. |
| Need 10µF to 22µF for power supply input filtering (12V rail) | Requires high voltage rating to avoid DC bias collapse. 25V or 50V rating needed. | 1206 (3216) or 1210 (3225) X7R, 25V. |
| Need > 47µF for low-frequency energy storage or audio coupling | MLCC ceramics become cost-prohibitive and mechanically fragile at this size. | Solid Polymer SMD (e.g., Panasonic SP-Cap) or 8x10mm Radial Electrolytic. |
| Need high voltage (> 100V) for snubber or AC line coupling | SMD ceramics above 100V require massive creepage distances. | 1812/2220 C0G/NP0 (if < 10nF) or Radial Film Capacitor (e.g., WIMA MKP). |
What the Chart Cannot Tell You (Edge Cases & Parasitics)
Physical dimensions and nominal capacitance only solve half the design equation. The chart cannot account for these critical real-world parasitics:
- Equivalent Series Resistance (ESR): Two 10µF 0805 capacitors in parallel will have half the ESR of a single 22µF 1210 capacitor. For switching regulator output filtering, lower ESR often matters more than raw capacitance.
- Piezoelectric Ringing (Microphonics): Large Class II SMD capacitors (1206 and larger, X5R/X7R) are piezoelectric. They can act as microphones, picking up acoustic noise, or act as buzzers, emitting audible whine under AC ripple. If your circuit is in an audio signal path, you must switch to C0G/NP0 dielectrics or film capacitors, regardless of the size chart.
- Mechanical Flex Cracking: Capacitors 1206 and larger are highly susceptible to cracking if the PCB bends during depanelization or connector insertion. If placing a 1210 or 1812 near a board edge or mounting hole, you must use a 'flex-termination' (soft-termination) variant from manufacturers like Kemet or Vishay, which adds a conductive epoxy layer to absorb mechanical stress.
By combining the EIA dimensional limits with DC bias derating curves and parasitic awareness, you can confidently lock in your capacitor footprint on the first schematic pass, avoiding costly PCB respins and BOM shortages.
