Turnkey PCB Assembly Cost: What a Quote Actually Includes

"How much does turnkey PCB assembly cost?" has no useful single answer. The same BOM assembled to the same workmanship standard can come back at several times one price and a fraction of another, and both numbers can be honest — they are pricing different scopes, at different quantities, on different dates.

The usable question is narrower: what is in the price, and are two quotes measuring the same things? This guide sets out the six cost blocks behind any turnkey quotation, a line-by-line anatomy of a complete one, and the checks that turn two incompatible totals into a comparison.

It deliberately stays on the document. Why a particular board is expensive to build — layer count, laminate, copper weight, surface finish, fine-pitch assembly — is a separate question, covered in the companion guide to custom PCB cost factors.

In short: ask for four numbers — conversion cost per board, materials cost per board, one-time charges as a separate line, and the date the component prices expire. Everything below is the detail underneath those four.

Figures here are arithmetic illustrations, not market prices. Any number quoted without a date and a quantity is a placeholder.

Contents

1. Why a single price per board misleads
2. The six cost blocks
3. Anatomy of a complete quotation
4. What to send before a quote can be built
5. Components: the line that moves most
6. Conversion: how assembly is priced
7. One-time charges
8. Test: the line most often missing
9. Cost and terms outside the quotation
10. The quantity ladder
11. How to compare quotes like-for-like
12. How KnownPCBA structures a turnkey quotation
13. FAQ

Why a single price per board misleads

A turnkey quotation contains costs of two natures, and blending them into one number hides the structure.

Variable costs scale with quantity: bare boards, components, placements, test time, packing, freight. One-time costs do not: stencils, programming, fixtures, first-article inspection, setup.

A supplier quoting a single figure — $14 per board at 100 pieces, say — has already decided how to recover the one-time charges, and you cannot see the decision. At 100 pieces those charges might be a third of the price. At 1,000 they might be 5%. Same board, same factory, different economics, and the blended number tells you nothing about which situation you are in.

This is not a criticism: a per-board price is what most buyers ask for. The problem appears at comparison time, when two suppliers have recovered their one-time charges at different assumed quantities. A turnkey PCB assembly cost breakdown is only useful if both quotations are built the same way.

The six cost blocks

Components and test account for most of the variance between quotations that claim to cover the same work.

Anatomy of a complete quotation

A quotation missing any of the first nine lines below is not necessarily wrong — it may simply be compressed — but the missing lines are exactly where comparison breaks down.

The layout is diagnostic. A single-number quotation has collapsed eleven lines into one, and you can now ask which were included. Turnkey PCB assembly pricing that arrives as eleven lines can be compared line by line against another.

What to send before a quote can be built

A quotation is only as specific as its inputs. Four packages decide whether the number that comes back is a price or a guess.

The BOM. Part numbers, package, quantity per board, brand preference, prohibited materials. A BOM that gives a value but no manufacturer part number cannot be priced — only estimated, and the estimate is replaced the moment sourcing starts.

Fabrication data. Gerber files, copper layer count, surface treatment, drill data and stack-up. Without a stack-up the fabricator prices an assumption, and assumptions are where the first revision comes from.

Pick-and-place data. X/Y coordinates, rotation and reference designators. This drives SMT programming, which is a one-time charge — a CPL with the wrong origin quietly adds setup time to the quote.

Project requirements. Quantity, urgency, test scope (AOI, ICT, FCT), packaging and logistics. Two buyers sending identical files with different test requirements receive different prices, correctly.

The turnkey PCB assembly page sets out the full scope, and component purchasing covers what the BOM review checks.

Components: the line that moves most

Components are usually the largest block and the least comparable between quotations. Five variables drive it.

Buying basis. Original manufacturer, authorized distributor and open-market stock are three markets with three prices and three risk profiles. A quote built on open-market pricing for an allocated part is cheaper and carries traceability risk an authorized purchase does not.

MOQ and packaging. A BOM calling for 47 pieces of a part sold only in 3,000-piece reels means buying 3,000. At low volume this excess can exceed the value of the parts actually placed. Ask for purchased quantity per line, not placed quantity, and whether assembly attrition is included.

Price validity. Distributor pricing on active parts can move weekly; pricing on allocated parts can move daily. A quotation is a snapshot with a date, and a PO issued after that date will see the component line repriced.

BOM coverage. The share of lines the supplier can source from stock or scheduled supply at the time of quoting. Low coverage means the quotation contains placeholders and the real component cost is still unknown — the first number to request when a quote looks unusually cheap.

Substitution policy. What matters is the rule: is an alternative approved before purchase, or placed and reported afterwards? The first preserves your control, the second preserves the schedule. The price difference is trivial next to discovering the policy at the wrong moment.

Conversion: how assembly is priced

Placement count and package mix. A 200-placement board of 0402 passives and a 0.4 mm-pitch BGA is not the same work as 200 placements of 0805 parts and SOICs. Fine-pitch placement needs slower machine settings, more nozzle changes and more inspection.

Sides. A double-sided build is two passes: two stencils, two setups, two reflows, and a second side that has to survive the first side's reflow.

Setup per unique BOM. Every distinct BOM carries feeder loading, programming, stencil mounting and first-article verification. On a high-mix order setup can dominate conversion cost — which is why 200 pieces of one variant can price lower than 200 spread across four.

One-time charges

NRE disappears from comparisons because it is not per board and therefore not in the per-board column.

The question is not "how much is NRE" but which charges recur on the next order, and which recur if you change one component. A stencil survives a BOM change. SMT programming does not.

Test: the line most often missing

Inspection is not test. AOI checks that the right part sits in the right place with a plausible joint; it cannot tell you whether the board works. X-ray checks joints hidden under BGA and QFN bodies. A quotation that says "tested" without naming the method has told you nothing. Acceptance class belongs here too — IPC-A-610 Class 2 and Class 3 differ in inspection time and rework rate rather than in a separate line, so a quote that omits the class is quoting to the supplier's default.

Functional test needs your inputs. A procedure, expected results, firmware and usually a fixture. A supplier can build and run a test but cannot invent your acceptance criteria; a quote offering functional test at no extra charge either applies a standard test that may not match, or has not priced the fixture.

Fixtures are tooling, not service. Worth building when volume justifies it, wasteful for a 50-piece prototype run where flying probe is the better answer.

Cost and terms outside the quotation

The quotation is not the cost. Five items sit outside it, and all five are the buyer's.

Freight mode. Air freight on a 20 kg shipment can exceed the conversion cost of a small order; sea freight costs less and adds weeks. It is a schedule decision as much as a cost decision.

Incoterms. EXW, FCA, FOB, DAP and DDP allocate freight, insurance, duty and clearance differently. FOB is a sea-freight term; an air shipment is properly quoted FCA, so a quotation saying FOB on an air shipment is worth a second look. Two quotes differing only in Incoterm are not comparable at all.

Duty and tax. Import duty, VAT or GST and brokerage depend on the tariff classification of the finished assembly, not on the supplier's price.

Tooling ownership. Stencils, fixtures and test programs are paid for by someone. Ask who owns them, whether they transfer if you move supplier, and whether they are kept or scrapped. A fixture you paid for and cannot retrieve is a cost you pay twice.

Schedule basis. Ask whether the delivery date runs from order or from material readiness. A date from order assumes components are available when the PO lands; a date from material readiness survives a shortage.

The quantity ladder

Take a hypothetical order with $1,000 in one-time charges and a $20 per-board variable cost — round numbers chosen to show the mechanic, not a quotation.

The per-board price falls by roughly 45% between 50 and 500 pieces without a single negotiation. Nothing about the factory changed; the one-time charges simply spread over more boards.

Two conclusions follow. A supplier who looks expensive at 50 pieces may be competitive at 500, so comparison is only meaningful at equal quantity. And if annual volume is 500 pieces, ordering 500 once is often cheaper than ordering 50 ten times, even after the cost of carrying inventory — the setup is paid once.

How to compare quotes like-for-like

How KnownPCBA structures a turnkey quotation

KnownPCBA is the PCB assembly business of the KnownPCB group, covering fabrication, component sourcing, assembly, testing and box build in one flow. Assembly runs on three high-speed SMT lines and two DIP lines, with daily capacity above 40,000 pieces and monthly capacity stable at one million. Inspection is AOI, 3D X-ray, ICT and functional test, with SPI at 2.8–20 μm precision and a 100 kV micro-focus X-ray at a 5 μm focal spot.

That matters to turnkey PCB assembly cost in one specific way: the price is built from the production package rather than from a board count. Gerber data, BOM, pick-and-place file, quantity and test requirements are reviewed together, so fabrication, sourcing, assembly and test preparation are all priced against the same revision — the eleven lines above, in the order they are incurred.

The BOM is screened for risk before sourcing is confirmed: unavailable, allocated, long-lead and end-of-life lines are identified at quotation, and engineers propose pin-to-pin alternatives for approval rather than substituting after purchase. Incoming material passes IQC for part-number verification, appearance and performance sampling. Nothing is subcontracted out, so one contact carries the order from DFM review to shipment.

Two commercial points are worth testing against any quote. Minimum order quantity is one piece with 48-hour rapid response, so a prototype run does not absorb a production-sized MOQ. And because fabrication, sourcing and assembly are priced in one flow rather than three, KnownPCBA puts the comprehensive cost at roughly 20% below segmented purchasing — the margin each separate supplier would have added, not a discount on one line.

The SMT manufacturing page lists the equipment, testing covers inspection scope, and PCBA design includes the free DFM review that runs before a quotation is issued. First builds are usually better routed through prototype PCB assembly than through a production quote.

FAQ

Why did two quotes for the same BOM differ by 40%? Almost always one of four things: a different buying channel on components, a different price validity date, a different fabrication specification, or a different test scope. Ask each supplier for purchased quantity per line, the price validity date, the full fabrication specification and the named test method.

Is the lowest per-board price the lowest total cost? Not usually. Add NRE, freight, duty and the cost of a late board. On first builds the delay cost frequently exceeds the price difference; on repeat orders the NRE treatment decides which supplier is cheaper over a year rather than over one order.

Do we pay NRE again on a repeat order? Stencils and SMT programming are normally reusable for the same board revision, so an unchanged design should carry little or no NRE. Changing a component, a footprint or the panel array can invalidate part of it.

Does a larger quantity always lower the price? The per-board price almost always falls, because one-time charges amortize. The total price never falls. And the fall is not smooth: it steps at quantity bands and at MOQ break points, so the cheapest quantity to order is sometimes just above a band boundary.

References and technical background

These define the specifications and terms used above. They do not establish supplier-specific prices.

1. IPC-6012 — Qualification and Performance Specification for Rigid Printed Boards. IPC. Acceptance classes for bare boards.
2. IPC-A-610 — Acceptability of Electronic Assemblies. IPC. Class 1, 2 and 3 workmanship criteria.
3. J-STD-033 — Handling, Packing, Shipping and Use of Moisture/Reflow Sensitive Surface Mount Devices. IPC/JEDEC.
4. Incoterms 2020 — International Chamber of Commerce. Defines EXW, FCA, FOB, DAP and DDP, and where cost and risk transfer. ICC Incoterms rules
5. Printed Circuits Handbook, Seventh Edition — Coombs and Holden. McGraw-Hill Education, 2016.

Want a quotation you can actually compare?

Send the Gerber data, BOM, pick-and-place file, quantity and testing requirements. KnownPCBA returns a quotation with conversion, materials and one-time charges shown separately, the test scope and acceptance class named, and a stated price validity date. Start your project — most enquiries are answered within one working day.