Costing & FinanceFree worksheetPDF, Excel, Word exportElectronics Manufacturing

PCBA BOM Cost Rollup Worksheet: Material Cost per Assembly

Every EMS quote and every standard cost starts with a priced BOM. This worksheet gives you a clean line-by-line rollup with overage, so you can see what drives material cost and export it for your costing file.

Download:

Reference designators	Manufacturer part number	Description	Process	Qty per board	Unit price	Overage %	Extended cost
							$3
							$9
							$0
							$0
							$1
							$0

Total parts per board

Material cost per board

$14

BOM lines

Average cost per line

Highest line cost

Prices are examples. Replace with current distributor or contract pricing at your build quantity. Add one row per unique line; use a range in reference designators for repeated parts.

Automate BOM costing from your ERP

An optional review of rolling BOM cost from your item and purchasing data.

Optional. The tool and every export work without this. No spam.

How to use it

Add one row per BOM line with reference designators, manufacturer part number and description, then the quantity per board, the unit price at your build quantity and an overage percentage. Pick the process to help filter later. Extended cost is calculated for each row and the totals show parts per board and material cost per board. Export to Excel to keep going or send the file to your buyer for quote validation.

Price at the break for the actual order quantity, not 1 piece
Add overage on small passives where fall-off is highest
Keep the same MPN as in your ERP item master

How overage works

Overage adds a percentage to purchased quantity to cover pick-and-place fall-off, setup consumption and reel-end losses. Chip passives typically need the largest overage because they are bought in reels and lost to machine faults, while expensive ICs get a very low overage. Many EMS shops also apply minimum overage counts for tiny parts, so for short runs a fixed number of extras may be more accurate than a percentage.

Common mistakes

The most common mistake is pricing at 1 piece when the order is thousands, which inflates cost, or the opposite, using a reel price for a prototype run and ending up with surplus stock. Another is leaving out non-BOM material such as solder paste, adhesives, labels and packaging. Finally, watch for minimum order quantities and packaging multiples: the cost you pay may be per reel, not per piece used. Compare the result with the cost estimator for labor and overhead.

Frequently Asked Questions

How do I add overage to a PCBA BOM?

Multiply quantity by one plus the overage percent. For example 40 pieces at 8 percent overage means buying 43.2, which you round up to whole pieces or reel lots. The worksheet applies the percent to cost for you.

Does this include assembly labor cost?

No, it is material only. Labor, machine time, test and overhead belong in a separate cost estimate. Use the PCB assembly cost estimator for those and combine the results.

Can I import my BOM from Excel?

You can edit rows directly in the table and export the result to Excel or CSV. Paste in your lines one by one, or use the exported file as the template for your own costing spreadsheet.

What price should I use for each part?

Use the price break matching your total order quantity, from your distributor quote or contract. For standard cost, many companies use a weighted average of recent purchases. Keep a note of the price source and date.

Netray can help pull current standard costs and last purchase prices from your ERP into a BOM view like this one, without rekeying.

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