A capacitor package size code describes the part’s footprint, not its capacitance. An 0805 MLCC is 2.0 × 1.25 mm; a tantalum “B” case is 3.5 × 2.8 mm; an aluminum “6.3 × 5.8” can is 6.3 mm across. This guide maps the common capacitor package sizes across the MLCC, tantalum, and aluminum electrolytic families to real dimensions, then covers the electrical and assembly consequences the plain size charts leave out.
Key takeaways
- MLCC (and resistor) codes are imperial EIA: 0402 means 0.04 × 0.02 in = 1.0 × 0.5 mm. The metric name for that same body is 1005 — a frequent BOM/CAD mismatch.
- Tantalum uses letter codes (A, B, C, D, E/X) mapped to EIA metric codes; “A” = 3216 = 3.2 × 1.6 mm.
- SMD aluminum electrolytics are named by can diameter × height in mm, e.g. 6.3 × 5.8.
- Package height is never in the code. It follows layer count (MLCC) or can length, so read it from the datasheet.
- Smaller isn’t free: a 4.7 µF 0603 MLCC can behave like ≈1.3 µF once biased (the DC bias effect).
How capacitor size codes actually work
The four-digit number on a chip capacitor is a dimension, not a value. In the EIA (imperial) system standard across North America, the two digit-pairs are body length and width in hundredths of an inch. So 0603 = 0.06 × 0.03 in = 1.6 × 0.8 mm.
The trap: the same digits mean different sizes in the two systems. Imperial 0201 (0.6 × 0.3 mm) is written 0603 in the metric (IEC) system — identical characters to the imperial 0603 code, but one-fifth the area. A CAD library set to the wrong convention will silently swap a 1.6 mm part for a 0.6 mm one, which wrecks SMT assembly. Always confirm whether a code is EIA-inch or IEC-metric before you lock a footprint.
What is a capacitor package size? It is the physical length and width of the component body, encoded as a four-digit number. In the imperial EIA system each pair is a dimension in hundredths of an inch, so an 0805 capacitor measures 0.08 × 0.05 in (2.0 × 1.25 mm). The code says nothing about capacitance or voltage rating.
[IMAGE 1: MLCCs from 01005 to 1206 on a fingertip for scale | alt: “capacitor package sizes compared from 01005 to 1206”]
MLCC (ceramic) package sizes
Multilayer ceramic capacitors are the workhorse surface-mount capacitor and run from 01005 to 2220 on the EIA scale.
| Imperial (EIA) | Metric (IEC) | L × W (mm) | L × W (in) | Typical use |
| 01005 | 0402 | 0.4 × 0.2 | 0.016 × 0.008 | Phones, wearables, HDI |
| 0201 | 0603 | 0.6 × 0.3 | 0.02 × 0.01 | Dense mobile, RF nodes |
| 0402 | 1005 | 1.0 × 0.5 | 0.04 × 0.02 | General decoupling |
| 0603 | 1608 | 1.6 × 0.8 | 0.06 × 0.03 | General purpose, hand-solderable |
| 0805 | 2012 | 2.0 × 1.25 | 0.08 × 0.05 | Bulk decoupling, bypass |
| 1206 | 3216 | 3.2 × 1.6 | 0.12 × 0.06 | Higher voltage/capacitance |
| 1210 | 3225 | 3.2 × 2.5 | 0.12 × 0.10 | High-cap bulk |
| 1812 | 4532 | 4.5 × 3.2 | 0.18 × 0.13 | High voltage, safety |
| 2220 | 5750 | 5.7 × 5.0 | 0.22 × 0.20 | High-cap / high-voltage |
Height is deliberately absent from the code: it grows with layer count, so a 10 µF X7R and a 100 pF C0G in the same 0805 case have different thicknesses. Volumetric limits bite at the small end — a 100 nF C0G fits comfortably in 0402, but 10 µF in 0402 pushes process capability (per Samsung’s CL-series data via PCBSync). High-cap MLCCs now reach 100 µF in 0805 and up to 220 µF in larger cases (Yageo HC series) — but, as below, that capacitance is heavily conditional.
Tantalum capacitor case sizes
Polarized tantalum chips use a letter code standardized to EIA metric case codes under EIA-535BAAC. These are the KEMET/EIA mappings from the T491/T493 datasheets.
| Code (KEMET) | EIA code | L × W × H (mm) | Max power dissipation @ 25 °C |
| A | 3216-18 | 3.2 × 1.6 × 1.6 | 75 mW |
| B | 3528-21 | 3.5 × 2.8 × 1.9 | 85 mW |
| C | 6032-28 | 6.0 × 3.2 × 2.5 | 110 mW |
| D | 7343-31 | 7.3 × 4.3 × 2.8 | 150 mW |
| X (E) | 7343-43 | 7.3 × 4.3 × 4.1 | 165 mW |
The power-dissipation column is what the generic size charts drop, and it matters: it caps ripple current per case through I(max) = √(Pmax / ESR) (KEMET T493 datasheet). Low-profile variants exist under separate letters — R (2012-12), S (3216-12), T (3528-12), U (6032-15), V (7343-20) — the same footprints as A–D but with capped heights of 1.2–2.0 mm for thin designs. Tape-and-reel follows EIA-481.
[IMAGE 2: tantalum chip showing polarity band and case letter | alt: “SMD tantalum capacitor A B C D case sizes with polarity band”]
SMD aluminum electrolytic (V-chip) case sizes
Cylindrical SMD aluminum electrolytics — “V-chips” — are named by can diameter × height in millimeters, seated on a square plastic base for pick-and-place.
| Case (D × L, mm) | Position in range | Typical capacitance seen |
| 4 × 5.4 | smallest common V-chip | up to ≈10 µF |
| 5 × 5.4 | small | ≈1–47 µF |
| 6.3 × 5.8 | mid | ≈10–100 µF |
| 8 × 10.2 | large | ≈47–470 µF |
| 10 × 10.5 | largest common | ≈100–1000 µF |
Across series, values span roughly 0.1 µF to 1500 µF, 4 V to 100 V, at −40 to +105 °C (up to +125 °C on high-temperature series), per Nichicon and Panasonic SMD listings. Capacitance available in a given can depends heavily on voltage and series — always confirm on the datasheet. Polymer and hybrid V-chips use the same case system with far lower ESR.
The size trade-off the chart won’t print: DC bias
This is where package size stops being cosmetic. Class 2 ceramic dielectrics (X5R, X7R) lose capacitance as DC voltage is applied, and the loss is worse in smaller cases because the dielectric layers are thinner. From Murata’s own model: a 4.7 µF 25 V X5R 0603 (GRM188R61E475KE15) measures about 1.3 µF at 10 V bias and barely 500 nF at its rated 25 V — close to a 90 % loss (StarFish Medical, using Murata data). Infineon’s side-by-side is blunter: at 3 V bias a 0603 holds ≈40 % of nominal while a 1206 of the same value holds ≈80 %.
Decision rule: for a Class 2 MLCC on a power rail, never design to the nominal value. Read the manufacturer’s DC-bias curve at your operating voltage, then upsize the case, raise the voltage rating, move to a more stable dielectric (X7R → X7S), or switch to tantalum/polymer, whose bias curves are effectively flat.
[IMAGE 3: capacitance-vs-DC-bias curve, 0603 vs 1206 | alt: “MLCC DC bias capacitance loss by package size”]
How to choose a capacitor package size
- Start from value and voltage, not footprint. Confirm the value exists in your target case at your rated voltage — 22 µF above 6.3 V rarely fits 0402.
- Derate for DC bias if it’s a Class 2 MLCC on a rail, and size up if the biased value falls short of what the circuit needs.
- Match the assembly process. 0805 and 1206 hand-solder and rework easily; 0603 is workable with practice; 0402 and 0201 need stencil, magnification, and machine placement.
- Account for board flex. Larger MLCCs (1206, 1210) crack more readily when the board bends because they span a longer distance; near edges and connectors, prefer smaller cases or flexible-termination parts.
- Default to stocked sizes. 0402/0603/0805 carry the deepest multi-vendor inventory; exotic cases invite lead-time and second-source pain.
Frequently asked questions
Are 0402 imperial and 1005 metric the same size?
Yes. Both name a body of 1.0 × 0.5 mm. “0402” is the imperial EIA code (0.04 × 0.02 in); “1005” is the metric code for the identical part. The mismatch to watch is imperial 0201 versus metric 0603, which share characters but not size.
Can I replace an 0603 capacitor with an 0402 of the same value?
Electrically often yes, if the voltage rating is adequate — but not on the same footprint. The 0603 land pattern is too wide for an 0402 to bridge both pads, so you must edit the PCB. Also check DC bias: the smaller part loses more effective capacitance under load.
Why does my 10 µF capacitor measure far less in circuit?
The DC bias effect. Class 2 MLCCs (X5R, X7R) shed capacitance as applied voltage rises, and smaller cases lose the most. A “10 µF” 6.3 V part on a 5 V rail can behave like a few microfarads. Use the datasheet’s bias curve, not the printed value.
What size is a tantalum “B” case?
EIA 3528-21: 3.5 × 2.8 × 1.9 mm, rated for about 85 mW dissipation at 25 °C. The letter maps to a standardized metric code, so a “B” is the same footprint across KEMET, AVX/Kyocera, and Vishay.
Which capacitor package size is easiest to hand-solder?
0805 and 1206. They are large enough for a standard iron and tweezers and tolerate rework; 0603 is manageable with practice and a fine tip; 0402 and smaller realistically need a stencil, microscope, and hot air.
The bottom line
Pick the package after the electrical answer, not before. Fix value, voltage, and dielectric first; for any Class 2 ceramic on a power rail, size the case from the biased capacitance you actually need, not the number on the reel. Then drop to the smallest stocked case your assembly process and board-flex margin allow. If the biased value or ripple rating forces a large MLCC, price a tantalum or polymer part in a B or C case before you commit — it is often smaller and far more predictable.
Suggested internal links: ceramic dielectric classes C0G/X7R/X5R → MLCC dielectric guide · capacitor voltage & DC-bias derating → derating guide · SMD land-pattern design → IPC-7351 footprint guide · tantalum vs polymer vs ceramic → capacitor technology comparison
External sources: content.kemet.com (T493) · starfishmedical.com (DC bias) · community.infineon.com (MLCC DC bias) · blog.knowlescapacitors.com (EIA case sizes) · forum.digikey.com (package sizing)
