Handle Part Shortages with Substitutes

A part is out of stock everywhere, discontinued, or suddenly three times the price. The design does not have to change, and the build does not have to wait: record what can replace the part, and PartsBox carries that knowledge through pricing, purchasing, and builds.

Say what can replace what, at the right level

Substitution works at three levels, matched to how sourcing decisions are actually made:

• A meta-part groups interchangeable parts under one name you put in the BOM — the natural fit for passives, where any of a dozen 0402 X5R 100nF capacitors will do. The meta-part shows the combined stock of all its members, and the choice of which member to buy is delayed until you order, when price and stock are known.
• Part substitutes give one part its own list of approved replacements, applied everywhere that part appears. The part stays in the BOM; each substitute keeps its own stock and history.
• A BOM substitute sets an alternate on a single BOM line in a single project — a customer-sanctioned swap for one build, and nowhere else.

You do not have to find the equivalents yourself. Open a part and PartsBox suggests likely substitutes, drawn from what other users treat as interchangeable, most common first. Review the specifications and add one with a click.

Substitutes work in pricing, purchasing, and builds

When PartsBox prices, purchases, or builds, it combines all three levels and treats the part and its substitutes as equally valid. Offers are gathered across the whole group and the best one is chosen from the combined pool, so a substitute can lower the price, not only cover a shortage. On a purchase list, the choice stays open until you place the order; in a build, an approved replacement in stock keeps the run moving when the primary part is gone.

Two rules keep substitution safe. A substitute must share the part's unit category, so a part measured by length is only replaced by another measured by length. And when the same part carries different substitutes in different places, PartsBox uses only the common ones, so a purchase never assumes a substitution you did not intend.

What to do when a part is unavailable

Check the part first: its substitutes and meta-part members may already cover the run from stock. If not, add a suggested substitute, or a part your engineer approves, at the narrowest level that fits — a BOM substitute for one project, a part substitute for everywhere, a meta-part when the group is the real identity. Then re-price the project: the offer pool now includes the alternates, and the best source may have changed.

Meta-parts, part substitutes, and BOM substitutes are in every plan, including the free Maker plan.