How to Read MLCC Part Numbers — Samsung Electro-Mechanics (CL) · Walsin part numbers field by field

Picture: An electronic parts shop. A customer in a tie holds an MLCC reel, peers at the long part number on the label and tilts his head, saying, “This long part number — I can’t tell what’s what…” The staff member in a red apron raises a finger and answers with a smile, “Each position has a meaning.”

MLCCs (multilayer ceramic capacitors) are the most numerous components on a board. Their bodies are so small that they carry no markings at all; the information is only in the part number on the reel label.

Each position in the part number has a fixed meaning, so once you know how to read it you can tell the size · capacitance · voltage · temperature characteristic without opening the datasheet. Using part numbers from Samsung Electro-Mechanics (CL series) and Walsin (Walsin Technology), the most widely used in Korea, we break them down field by field.

1. Common rules to know first

① Capacitance is 3 digits. Add as many zeros after the first two digits as the third digit says; the unit is pF (picofarads). 104 = 10 followed by four zeros = 100,000pF = 100nF = 0.1µF. Small values below 10pF use R as the decimal point (1R5 = 1.5pF).

② Temperature characteristic (dielectric) is written like X7R · X5R · C0G. In X7R, the first letter X = minimum -55℃, the digit 7 = maximum +125℃, and the final R = capacitance change of ±15% over that range. C0G (NP0) is a Class 1 ceramic whose capacitance barely changes with temperature, so it is used in precision circuits. Inside part numbers these names are not used as is; each company abbreviates them to a single letter of its own (sections 2 and 3 below).

③ Tolerance letters are the same at both companies: J ±5% · K ±10% · M ±20% (below 10pF: B ±0.1pF · C ±0.25pF · D ±0.5pF).

2. Samsung Electro-Mechanics part numbers (CL…)

Samsung Electro-Mechanics MLCC part numbers are 15 characters long, divided into 11 fields. Example: CL10A105KA8NNNC = 0603 size · 1µF · 25V · X5R · ±10%. The codes used in each field are shown below.

② Size code — the mm size shortened to two digits (be careful not to confuse it with inches)

The code follows two rules.

• 1608 and larger — first digit of the length + first digit of the width in mm: 1608 → 10 · 2012 → 21 · 3216 → 31 · 3225 → 32
• 1005 and smaller — the last two digits of the 4-digit mm size as they are: 1005 → 05 · 0603 → 03 · 0402 → 02

So you can work the size back out from the code alone. For example, 21 means a length in the 2mm range and a width in the 1mm range = 2012mm (0805inch).

③ Dielectric code

⑥ Rated voltage code — the voltage is written as a single letter

⑦~⑪ Remaining fields

3. Walsin part numbers (0603…)

Walsin (Walsin Technology, Taiwan) general-purpose MLCC part numbers have 7 fields. Example: 0603B104K500CT = 0603 size · 100nF · 50V · X7R · ±10%. Unlike Samsung, the size uses the inch number as is and the voltage is 3 digits.

② Dielectric code

⑤ Rated voltage — like capacitance, first two digits + number of zeros; R is the decimal point

Sizes are 0201 · 0402 · 0603 · 0805 · 1206 · 1210 · 1812 (inch). The trailing C means Cu/Ni/Sn terminations, and T means a 7-inch reel (G is a 13-inch reel).

4. Easy-to-miss traps

Picture: A customer holds MLCC reels from two companies, one in each hand. Both labels show a large letter A. The customer, looking surprised, says, “Same A, but different meanings?” and the staff member, arms crossed, answers, “Each company has its own table.”

• Same letter, different meaning — In the dielectric field, A is X5R at Samsung but X7S at Walsin. X is X6S at Samsung and X5R at Walsin. About the only one the two share is B = X7R. Reading one company's part number with the other's table will give you the wrong answer.
• Two kinds of 0603 — "0603" usually means inches (1.6 × 0.8mm). But 0603 in mm is inch 0201 (0.6 × 0.3mm), which is much smaller. Samsung's size code 03 is exactly this small one, and the 0603 we usually talk about is 10 at Samsung.
• Voltage notation — 25V is the letter A at Samsung and the number 250 at Walsin. In Samsung part numbers, A means different things depending on whether it is in the dielectric field (3rd) or the voltage field (6th).

5. Same specs, two companies' part numbers

If the specs are the same, they can often be used in the same position even though the company differs. Here are two common ones side by side (click a part number to find stock in eGuro Part Search).

※ Before substituting, check the datasheet for thickness (height limits), temperature characteristic, and — for X5R · X7R — how much the actual capacitance drops as the applied voltage rises (DC bias), which differs by company.

6. How to read a reel label

How to Read MLCC Part Numbers · Reel Label

4 places to check on a reel label

Example

P/NManufacturer part number

The part number explained in this post. Match it character by character against the drawing or purchase order

Q'TYReel quantity

0603 usually comes 4,000 per 7-inch reel (varies by size, thickness and packaging)

LOTProduction lot number

A number the manufacturer uses for tracing if a quality issue arises

D/CManufacturing date (Date Code)

Usually 2-digit year + 2-digit week (2542 = week 42 of 2025). The format varies by manufacturer

※ Label layout and order vary by manufacturer and period. The barcode usually contains P/N · quantity · LOT

Example illustration — actual label layout and order vary by manufacturer and period

On the reel label, first match the P/N (part number) against your order character by character, then check Q'TY (quantity), LOT (production lot) and D/C (date code). D/C is commonly 2 digits of year + 2 digits of week (2542 = week 42 of 2025), but the format differs by manufacturer.

Sources: Samsung Electro-Mechanics MLCC catalog (January 2024) Part Numbering · Walsin Technology General Purpose MLCC approval sheet (October 2026) How to order. Codes are based on general-purpose (standard) products; other series such as automotive and high-voltage may differ in some fields.