SMT Package Sizes: 01005 to 1206 Compared

An SMT package size is a four-digit code that tells you the length and width of a chip resistor, capacitor, or inductor — in hundredths of an inch. A 0402 is 0.04 in × 0.02 in (1.0 mm × 0.5 mm); a 1206 is 0.12 in × 0.06 in (3.2 mm × 1.6 mm). The code is purely physical: it says nothing about value, voltage, or power on its own. Pick too small and you fight tombstoning and starved power ratings; pick too big and you waste board area and routing channels.

This guide compares every common chip package from 01005 up to 1206 — exact dimensions, power ratings, hand-solder difficulty, and the metric-versus-imperial trap that ships wrong parts — so you can choose the right footprint once and move on. The codes 0402, 0603, 0805, and 1206 cover roughly 70–80% of general-purpose passive designs, so most of your decisions live right here.

SMT Package Sizes at a Glance

• 0402, 0603, 0805, 1206 are the workhorse “jellybean” sizes; 0603 is the modern default, 0805 the easiest production-relevant size to hand-solder.
• The size code is imperial (hundredths of an inch). The metric code (mm × 10) shares numbers with other imperial sizes — metric 1005 = imperial 0402, and metric 0402 = imperial 01005. This collision ships wrong parts.
• Power rating scales with body size: roughly 1/16 W (0402) → 1/10 W (0603) → 1/8 W (0805) → 1/4 W (1206) for standard thick-film resistors.
• Below 0402, hand soldering and visual rework become impractical; 0201 and 01005 need fine-pitch pick-and-place and 3D AOI.
• Shrinking a part isn’t free — it cuts power headroom and raises tombstoning and cracking risk, often costing more in yield than the board area saves.

What Is an SMT Package Size and How the Code Works

The package code is a shorthand for the component’s footprint. Read the four digits as two pairs: the first pair is length, the second is width, both in hundredths of an inch. So 0805 means 0.08 in long by 0.05 in wide. These rectangular two-terminal packages — the chip family — are used for the overwhelming majority of resistors and multilayer ceramic capacitors (MLCCs), and for many small inductors too.

Two things the code does not tell you: height and electrical rating. Height is a separate dimension that varies within one footprint — a high-capacitance or high-voltage MLCC in an 0805 body can be far taller than a thin-profile 0805, which matters for low-clearance enclosures. And two parts with identical 0603 footprints can carry wildly different power or voltage ratings depending on construction. The code fixes the land pattern; the datasheet fixes everything else.

These chip packages are one half of the surface-mount world. If you’re still deciding whether to use surface-mount parts at all versus leaded ones, the broader case is covered in our guide on SMD vs THT; this article assumes you’ve chosen SMT and now need to size the passives.

SMT Package Size Chart: Dimensions, Metric Code, and Power

Here’s the master reference. Dimensions are nominal body size for chip resistors and MLCCs; power ratings are typical maximums for standard thick-film resistors at 70°C ambient and will vary by series, so always confirm against the datasheet.

Imperial	Metric (mm)	Size (mm)	Resistor Power	Typical Use
01005	0402	0.4 × 0.2	1/32 W	Phones, hearing aids, ultra-dense wearables
0201	0603	0.6 × 0.3	1/20 W	Smartphones, earbuds, dense consumer boards
0402	1005	1.0 × 0.5	1/16 W	Mainstream high-density; RF decoupling
0603	1608	1.6 × 0.8	1/10 W	General-purpose default; IoT, MCU boards
0805	2012	2.0 × 1.25	1/8 W	Prototyping sweet spot, moderate power
1206	3216	3.2 × 1.6	1/4 W	Power, current sense, high-voltage, LED strips

Notice the metric column. The metric name is the body size in tenths of a millimeter, so the imperial 0603 (1.6 × 0.8 mm) is metric 1608. That’s harmless until the numbers overlap with a different imperial size — which is exactly the next problem.

Metric vs Imperial SMT Codes: The Trap That Ships Wrong Parts

US and many East-Asian datasheets default to imperial (0402, 0603); European manufacturers and modern CAD libraries lean metric (1005, 1608). Both name the same physical parts — until the digits collide. Here’s the truth: the metric name of one part can be identical to the imperial name of a much smaller part.

The two collisions that bite:

• Metric 1005 = imperial 0402 (1.0 × 0.5 mm). If a Chinese fab quotes “1005,” they almost certainly mean your 0402 — not the imperial 1005 (a giant 2.5 × 2.0 mm part).
• Metric 0402 = imperial 01005 (0.4 × 0.2 mm). A line item that says “0402 metric” is the tiniest mainstream chip there is, ten times smaller in area than the 0402 you probably intended.

Counterintuitive insight #1: the same string — “0402” — refers to two real, orderable parts whose areas differ by roughly 10×. The naming systems were never reconciled, so the code alone is ambiguous. A buyer who copies “0402” from a metric datasheet into an imperial-expecting purchase order can receive 01005 parts that won’t even register on the intended pads.

There’s also a standards angle. EIA imperial codes and IEC/metric codes describe the same chips, and IPC’s footprint naming (RESC for chip resistors, CAPC for chip capacitors) is built on the metric body size — so an IPC “RESC1608” land pattern is your imperial 0603. Mixing the two naming worlds in one library is how footprints end up subtly wrong.

Do this to kill the ambiguity for good:

1. List both codes in every BOM line — e.g. “0603 (1608 metric)” — and state the system explicitly.
2. Put the physical mm dimensions in the BOM and the CAD library part name, not just the code.
3. When a supplier quotes a bare metric number, confirm the mm size before you release the PO.

How Package Size Affects Power, Heat, and Reliability

Body size is thermal mass and surface area. A bigger package has more ceramic volume, thicker terminations, and more contact area to sink heat into the copper — which is why power rating climbs with size. Push a 0402 past its ~1/16 W limit and it heats fast: resistance drifts, the part ages, and in the worst case the element cracks. Most chip resistors also derate above 70°C, and the smaller the body, the steeper the derating curve.

Counterintuitive insight #2: going smaller can hurt signal integrity less but reliability more. A smaller body genuinely lowers parasitic inductance and capacitance, which helps RF decoupling and high-speed matching — that’s a real reason to choose 0402 on those nets. But the same low mass and short pad span make the part far more prone to tombstoning during reflow and to cracking when the board flexes. On a long board, an LED strip, or anything that sees vibration or bending, the larger 0805 or 1206 is the more reliable choice even though it “looks” less advanced.

Mechanical cracking is the quiet failure mode. Ceramic chip caps are brittle; board flex during depaneling, connector insertion, or mounting can fracture an MLCC and produce an intermittent or shorted part weeks later in the field. Larger bodies tolerate more strain, and orientation relative to the flex axis matters. This is also where land-pattern discipline pays off — symmetric pads and balanced copper, per IPC-7351, reduce both tombstoning and stress concentration.

Real-world case: a wearables startup shrank every passive from 0603 to 0402 late in layout to claw back board area, then shipped about 5,000 units. Field returns climbed over the next two months — intermittent resets traced to tombstoned and microcracked 0402 parts on a board that flexed slightly in its strap-mounted enclosure. The fix was selective: 0402 stayed on the dense RF section where parasitics mattered, but the flex-prone power and reset nets went back to 0603 with balanced thermal-relief pads. Returns on the reworked revision dropped to near zero. The lesson: size per-net to the stress and power it actually sees, not one global rule for the whole board.

How to Choose the Right SMT Package Size

Work through these in order — space is rarely the first constraint that should decide it.

• Power first. Calculate worst-case dissipation (P = I²R or V²/R) and pick a package rated 20–30% above it. If you need 0.1 W, an 0603 (1/10 W) is marginal — step to 0805 (1/8 W) for headroom.
• Voltage and creepage. Higher voltage needs more terminal-to-terminal spacing; 1206 tolerates up to ~200 V where a tiny chip will not. High-voltage MLCCs also force a bigger body for dielectric thickness.
• Assembly reality. Hand-built prototype or frequent rework? Stay at 0805 or 0603. Going to 0201/01005 means your assembler needs fine-pitch placement and 3D AOI — confirm capability before you commit.
• Mechanical stress. Flexing, vibration, long boards, automotive? Prefer 0805/1206 and mind orientation to the bend axis.
• Then density. Only after the above, shrink to 0402 (or smaller) where board area genuinely demands it — typically the dense, low-power signal regions.

For the resistor-specific deep dive — power tables, parasitics, and a package-by-package selection walkthrough — see our breakdown of SMD resistor sizes, which expands on the trade-offs summarized here.

Common SMT Package Size Mistakes (DFM Checklist)

Hand this list to anyone selecting parts or building a CAD library:

• Treating the code as metric when it’s imperial (or vice versa) — the 0402/01005 collision. Always state the system and the mm size.
• Shrinking a package purely to save board space, ignoring the power and thermal-derating hit.
• Comparing only length and width and forgetting height — a tall MLCC in a short enclosure fails mechanical fit.
• Over-speccing voltage so the part jumps to a bigger body that no longer fits the intended footprint.
• Choosing sub-0402 parts without confirming the assembler has fine-pitch placement and AOI.
• Unbalanced pads or one pad tied to a copper plane and the other to a thin trace — uneven heating causes tombstoning. Use thermal reliefs to balance it.
• Hand-drawing footprints instead of using IPC-7351 land patterns from your CAD library — wrong pads cause more field failures than wrong values.
• Using 0402 on mechanically stressed or flexing boards where 0805/1206 would survive.

Five Things to Do Monday

• Audit your CAD library: confirm each chip footprint is tagged imperial or metric, and add the mm size to the part name.
• Add both code systems plus mm dimensions to every passive line in your BOM template.
• Re-check any net dissipating real power — bump marginal 0603 power resistors to 0805/1206.
• Verify your assembly partner’s minimum component size and AOI capability before locking sub-0402 parts.
• Replace any hand-built chip footprints with IPC-7351 Nominal (Level B) land patterns from a validated library.

Frequently Asked Questions About SMT Package Sizes

What is the most common SMT package size?

0603 (1.6 × 0.8 mm) is the most common general-purpose size for resistors and capacitors, balancing density and manufacturability. 0402 dominates space-constrained consumer devices like phones, while 0805 and 1206 remain popular for prototyping and power applications. The four together cover most passive designs.

Is 0402 metric the same as 0402 imperial?

No — and this confusion ships wrong parts. Imperial 0402 is 1.0 × 0.5 mm. Metric 0402 is 0.4 × 0.2 mm, which equals imperial 01005, about ten times smaller in area. Always confirm which system a datasheet or supplier uses, and list the mm dimensions.

What is the smallest SMT package size?

01005 (imperial), measuring 0.4 × 0.2 mm, is the smallest mainstream chip package, used in phones, hearing aids, and medical implants. It requires high-precision pick-and-place and 3D AOI; hand soldering is effectively impossible. Smaller experimental sizes exist but are rare in production.

What size SMD can you hand solder?

0805 is comfortable for most people; 0603 is doable with a fine tip, flux, and magnification; 0402 is possible but frustrating without a microscope and steady hands. Stick to 0603 or larger for hand-built prototypes and rework. Below 0402, use automated assembly.

Can I put a 0402 component on 0603 pads?

Not reliably. The 0603 pads sit farther apart than a 0402’s terminals, so the part may not bridge both pads, producing weak joints or tombstoning. Substituting sizes requires a matching footprint. Resistance or capacitance value can stay the same, but the land pattern must fit the body.

How does package size affect power rating?

Larger bodies dissipate more heat, so power rating rises with size: roughly 1/16 W for 0402, 1/10 W for 0603, 1/8 W for 0805, and 1/4 W for 1206 in standard thick-film resistors. Most parts also derate above 70°C, with smaller packages derating more aggressively.

Do capacitors use the same package sizes as resistors?

Chip MLCCs share the same length-and-width codes (0402, 0603, 0805) as resistors, so the footprints align. But capacitor height varies widely within one code, and higher voltage or capacitance often forces a larger body. Tantalum capacitors use separate molded case codes (A, B, C, D, E) instead.

Picking the Right SMT Package for Your Board

Sizing SMT packages comes down to a clear order of priorities: power and voltage first, assembly and mechanical reality next, board density last — and labeling every part with both its imperial and metric code plus its millimeter dimensions so the right component actually shows up. Treat 0603 as your default, reach for 0805 or 1206 when power or stress demands it, and drop to 0402 or smaller only where space truly forces the issue and your assembler is equipped for it.

Not sure a size choice will survive your reflow profile or board flex? Send us your Gerber and BOM and we’ll run a free DFM review, flagging any package, footprint, or metric/imperial mismatch before the parts are ordered.