The short answer
A complete PCBA quotation request contains nine inputs. Seven are technical: fabrication data, a BOM with manufacturer part numbers, a centroid file, an assembly drawing, a quantity and schedule, a test requirement, and a board specification including surface finish. Two are commercial: the sourcing model and the shipping destination.
Every input maps to a number on the quotation. When one is missing, the number cannot be calculated, so the supplier either asks a question or fills the gap with an assumption. The question costs a round trip. The assumption costs more, because it is discovered later.
This page lists the nine, states what each one fixes in the price, and shows what we have to ask when it is absent.
The nine inputs and what each one decides
Read the third column as a list of things that will be asked anyway. Sending them up front is not extra work, it is the same work done once.
| Input | What it decides | If it is missing |
|---|---|---|
| Gerber and drill | Whether the bare board can be built | We cannot quote fabrication at all |
| BOM with part numbers | Component cost, lead time, alternates | Component price is a placeholder |
| Centroid file | Placement time, stencil, machine program | Assembly cost is estimated, not quoted |
| Assembly drawing | Polarity, variant, parts not fitted | An assumption becomes rework |
| Quantity and schedule | Setup amortisation, material buy | Unit price holds only at one volume |
| Test requirement | AOI, ICT, functional, X-ray, labour hours | We assume AOI only |
| Board specification | Finish, thickness, copper, impedance | Finish assumptions get priced later |
| Sourcing model | Who buys parts and holds the risk | Component cost cannot be fixed |
| Ship destination and terms | Freight, duty, packaging, Incoterms | Delivered cost is unknown |
The three files that decide whether the quote is real
Fabrication data means Gerber in RS-274X, one file per layer, plus an Excellon drill file with plated and non-plated holes separated and slots defined. The board outline must be present on its own mechanical layer. A PDF drawing is useful context but it cannot be fabricated.
The BOM must carry manufacturer part numbers, reference designators and quantity per board, with do-not-populate lines marked as such rather than deleted. Deleting them is the most common cause of a second quote round, because the centroid file still contains those positions and the two documents no longer agree. State whether substitutes are allowed; "no substitutes" is a legitimate instruction with a price.
The centroid file gives X and Y in millimetres, rotation, side and designator for every placement. Rotation conventions differ between CAD tools, so a file exported from Altium and one exported from KiCad will not agree on a 180-degree part. We verify rotation against the assembly drawing, which is why the drawing is not optional.
The two inputs that change the number
Quantity sets the setup amortisation. A single SMT program changeover is a fixed cost regardless of whether the run is 10 boards or 1,000, so a quote for 10 and a quote for 1,000 are not the same price per unit scaled. If there is an annual volume, say so, because material buying differs between a one-off and a repeat.
The sourcing model decides who owns component price and inventory risk. A turnkey quote fixes a component price for a stated validity window. A consignment quote prices placement only, and your component cost appears nowhere on it. Both are quotable; the difference is which risks move to your books, as set out in the turnkey versus consignment comparison.
The three inputs that change the process
An assembly drawing carries what data cannot: polarity marks, connector orientation, shield cans, press-fit positions, conformal coat keep-out, and the variant logic for builds that share a PCB but differ in fittings. Without it, variant 2 gets built as variant 1 often enough to matter.
The test requirement sets labour hours and fixtures. AOI is the default and is included in most quotes. ICT needs test points designed in and a fixture built, which is non-recurring engineering and can exceed the assembly cost on a small run. Functional test needs a specification from you, and this is the one input we cannot invent. PCBA testing and inspection sets out what each method actually verifies.
The board specification fixes surface finish, finished thickness, copper weight and any impedance target. Surface finish is the most consequential line item here because it decides flatness at fine pitch as well as cost, which is why it has its own comparison in surface finishes compared.
The input nobody sends: shipping terms
Destination country, Incoterms and who is the importer of record determine freight, duty and packaging. On a US-bound order in 2026 this is not a footnote: rates for Chinese boards and assemblies changed on 10 November, and the difference between DDP and FOB is a real number, not a formality. The tariff status summary covers the codes and the scenarios.
What one missing input actually costs
A round trip is one to three business days: question out, answer back, quote revised. Two rounds is a week. On a fifteen-day build that is seven percent of the schedule before anything is manufactured.
There is a second cost that is easier to miss. A quote is only useful while its validity holds, and laminate pricing has been moving monthly through 2026, as the FR-4 cost supercycle explains. A quotation delayed by a week of questions can expire before it is approved, and the replacement will be priced at the new material cost.
The cheapest quotation round is the first one. Every input you send up front is a question we do not have to ask, and a week you do not spend waiting.
How to send it in one message
Put everything in one archive named with project, revision and date. Inside it, use four folders: fabrication, BOM, placement, drawings. Write the ask in the first line of the email — quantity, target date, and whether you want turnkey or consignment.
If you also need bare boards quoted, the combined request is described in the PCB and PCBA quote checklist, and the file naming and layer conventions are in the manufacturing file checklist. For the assembly scope itself, our PCBA services page lists what we build in-house, and component sourcing explains how a BOM becomes a purchased kit.
Send the nine inputs and you get one quotation rather than a correspondence. If a file is missing, tell us which one and we will quote the rest and flag the gap, instead of holding the whole request.
Questions, answered
Before your next build
Which inputs can be simplified for a five-board prototype?
Quantity and schedule simplify; nothing else does. A prototype still needs Gerber, BOM, centroid and drawing, because the same program runs whether the run is five boards or five hundred. Test can default to AOI for a prototype if no functional test exists yet.
Can you quote assembly from a BOM and a drawing without Gerber?
We can give an indicative placement cost, but not a firm one. Placement time depends on the actual pad geometry and panel layout, and both live in the fabrication data. Any number given without it will be revised.
Do I need a separate centroid file if my CAD tool can export ODB++?
Not necessarily. ODB++ carries placement data, and we can extract it. Send the assembly drawing anyway so rotation and side can be verified against your intent rather than our interpretation.
How long is a PCBA quote valid?
Fifteen to thirty days depending on the component content, stated on the quotation. Component prices move faster than fabrication prices, so a quote heavy in allocated parts will carry the shorter window.