How to Prepare a BOM for a Component Quote, and How to Read the Quote You Get Back

A BOM that gets a fast, accurate quote has one row per part and four things in every row: the complete manufacturer part number with every suffix, the manufacturer, the total quantity you want to buy, and whether alternates are acceptable. Add the packaging you need, any date-code limit and the date you need the parts, and a distributor has everything required to quote. Reference designators and footprints are what an assembler needs; for buying parts they are optional.

We quote complete customer BOMs, and nearly every slow or wrong quote traces back to the same few gaps: a part number missing its last characters, a quantity per board instead of per order, a packaging requirement nobody wrote down. This guide covers the format that avoids them, the suffix conventions of major manufacturers, a sample file, and how to check the quote that comes back.

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The columns that matter

Octopart's BOM tool, for example, requires the MPN column and "strongly recommends" a manufacturer column (Altium/Octopart). If the same file also goes to an assembler for turnkey work, keep the designators, footprints and do-not-place marks: JLCPCB requires Comment, Designator and Footprint columns (JLCPCB), and PCBWay doesn't accept BOMs as PDF files (PCBWay).

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Write the complete part number

The characters at the end of a part number encode the package, the temperature range, the packaging and sometimes the RoHS or automotive status. Leave them off and the supplier has to guess. JLCPCB's own guide puts it bluntly: a shortened MPN "forces the assembler to guess" (JLCPCB).

Two details catch people out:

• The packaging code usually isn't on the chip. TI's TPS7A26 carries only "7A26" on the package, and Microchip states that its T is "not printed on the device package". Only the reel label and the order line show what you bought.
• The same letter means different things at different manufacturers. T is a 250-piece reel at TI, a tape-and-reel flag at Microchip and a package code inside an STM32 number. Q1 means automotive at TI, but in NXP packing documents "Q1/T1" describes the orientation of pin 1 on the tape.

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Passives: describe them fully or name the part

For resistors and capacitors, many teams accept any brand. That is fine, but say so, and give every parameter that matters:

• value with its unit: "100nF", not "100n";
• tolerance, rated voltage, dielectric (C0G, X7R, X5R) or power rating;
• case size, stating imperial or metric. Imperial 0603 is 1.6 × 0.8 mm (metric 1608), while metric 0603 is 0.6 × 0.3 mm (imperial 0201). Mixing the two systems is one of the most common BOM errors;
• grade, such as AEC-Q200 for automotive.

Or name a specific part and allow equivalents. Vishay's CRCW0603562RFKEA reads as 0603, 562 Ω, ±1%, ±100 ppm/K, packaging code EA; the same resistor comes as 5,000 pieces on a 7-inch reel (EA), 10,000 on a 7-inch reel (ED) or 50,000 on a 13-inch reel (EE) (Vishay). For generic lines, Octopart suggests a consistent naming scheme such as "RES_10K_1%_0603" (Altium/Octopart).

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Quantities: the total to buy, attrition included

Give the quantity you want to buy. If your BOM lists quantity per board, add the build quantity and a total column, and check that the number of designators matches the quantity on each line; mismatches are among the first things BOM checkers flag (Sierra Circuits).

For assembly, add attrition: the parts lost when feeders are loaded and during picking. There is no single standard figure:

Ask your assembler for its numbers; some treat missing attrition as a parts shortage (Sierra Circuits). When the total lands close to a full reel, ask for the full-reel price as well: the reel price break sometimes makes the larger quantity cost little more.

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Packaging: say what your line can use

Pick-and-place feeders need empty tape at the start of a reel. ST's reels, for example, have a leader of at least 400 mm, including at least 100 mm of empty sealed pockets, and a trailer of at least 160 mm (ST TN1204). Assemblers ask the same of cut tape: ACDi wants 3 inches of empty pockets or extra parts at the start of each strip.

MOQ, SPQ and MPQ are not defined by any formal standard, and suppliers use them slightly differently. Usually the MOQ (minimum order quantity) is the smallest quantity a seller will sell, the SPQ (standard pack quantity) is the quantity in one manufacturer pack, such as a full reel, and the MPQ is the pack size orders must be multiples of. When a quote shows any of them, ask how that supplier uses the term.

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Alternates: decide before you ask

Give the alternates column one of a few clear values:

• No: exact part number only.
• Variant: the same part in another package option or a wider temperature grade is fine.
• Equivalent: any manufacturer, same footprint, specifications equal or better.
• Suggest: propose options and we will qualify them.

Keep approved alternates in their own column or row; JLCPCB's advice is never to mix primary and alternate parts in the same MPN field. Treat any alternate in a quote as a proposal until you have qualified it. Assemblers that kit parts work the same way: ACDi flags parts that don't match the customer's approved vendor list and waits for approval. For microcontrollers in particular, "pin-compatible" is not "firmware-compatible"; see our guide to STM32 pin-compatible alternatives.

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Date codes, documents and compliance

• Date codes. If your quality system limits date-code age, put the limit in the BOM, per line or for the whole file. Even large distributors can't promise a specific date code; DigiKey accepts a range request in the order notes (DigiKey). Our guide to date codes and shelf life explains when older stock is fine.
• Certificates of conformance. Ask for them in the RFQ; DigiKey, for one, requires the request at the time of order.
• Environmental declarations. RoHS restricts ten substances (European Commission), and REACH requires safe-use information when an article contains a substance of very high concern above 0.1% by weight. Say if you need declarations.
• End use. Some manufacturers require an end-use statement for export control before they ship. Having the end product and end customer ready saves days.

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A sample BOM

A build of 1,000 boards. Copy it into a spreadsheet or save it as a .csv file.

Line,MPN,Manufacturer,Qty,Alternates,Packaging,DC limit,Need by,Notes
1,STM32F103C8T6,STMicroelectronics,1020,No,Tray,2024+,2026-12-01,1 per board + 2%
2,TPS7A2601DRVR,Texas Instruments,1050,No,Full reel,,2026-12-01,1 per board + 5%
3,MMBT3904LT1G,onsemi,3000,Equivalent,Full reel,,2026-12-01,2 per board; full reel price
4,CRCW0603562RFKEA,Vishay,5000,Equivalent,Full reel,,2026-12-01,4 per board; 0603 imperial
5,ADuM1201ARZ-RL7,Analog Devices,1010,No,Full reel,,2026-12-01,1 per board + 1%

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How to read the quote you get back

Lifecycle terms

Manufacturers use their own words. At TI, NRND (not recommended for new designs) means the part is available for existing designs, but TI recommends an alternate for new ones; last time buy means the part is being discontinued; obsolete means it is no longer in production (TI). "EOL" is common shorthand, not a status in TI's or ADI's published lists. Discontinuance notices follow JEDEC J-STD-048A, published in December 2025; TI, for example, gives 12 months to place last orders and 6 more to take delivery (TI). Our EOL management guide covers what to do next.

Incoterms in one table

Incoterms 2020 is the current edition of the ICC rules (ICC). The rules that show up most in component quotes:

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Red flags in a quote

• A different suffix from the one you asked for, with no explanation.
• A price far below authorized-distributor pricing for a part that is allocated or discontinued.
• No date code, or "mixed" with no breakdown.
• "In stock" with a delivery time of several weeks.
• Refusal to send photos of the labels before shipment.

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Send us your BOM

Upload your BOM as Excel or CSV in the BOM form, or send it to [email protected]. We quote every line, not just the easy ones, with a multi-source price comparison and a complete BOM quote within 24-48 hours, and ship everything consolidated: one PO, one shipment, one invoice. More on our BOM fulfillment and kitting service.

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FAQ

What is the difference between MOQ, SPQ and MPQ?

No standard defines them, and suppliers use them a little differently. Usually MOQ is the smallest quantity a seller will sell, SPQ is the quantity in one manufacturer pack (for example, a full reel), and MPQ is the pack size orders must be multiples of. Ask the supplier how it uses the term.

Do I need reference designators in a BOM for a component quote?

Not for buying parts: the part number, manufacturer and total quantity are enough. Assemblers do need designators, footprints and do-not-place marks, so keep them if the same file goes to assembly.

Can I send my BOM as a PDF?

Send a spreadsheet (XLSX or CSV). Distributors match lines automatically, and assemblers such as PCBWay don't accept PDF BOMs. Retyping a PDF adds errors.

How much attrition should I add for SMT assembly?

There is no single standard. Published figures range from 0.5% on large ICs to 25% on 0201 passives, depending on the assembler and part size. Ask your assembler for its numbers before you order.

What do R and T at the end of a TI part number mean?

Both are tape and reel. R is the large reel (often 3,000 pieces, depending on the package) and T is the small reel of 250. Neither letter is printed on the chip.

How long is a component quote valid?

Authorized distributors often hold quoted prices for 30 days; Farnell and DigiKey online quotes both do. Open-market quotes for scarce or end-of-life parts can be valid for a day or less, because the stock can sell to someone else.