What is a Hollander interchange number?
A Hollander interchange number is a code that groups auto parts that are interchangeable - parts that physically fit and function on more than one vehicle, even across different makes, models, or years. If two vehicles share the same interchange number for a given part, that one part fits both. It is the auto-recycling industry’s de-facto standard for describing fitment, created in the 1930s and covering most vehicles on US roads.
For a used-parts seller, the number does two things: it widens reach (your part is found by buyers of every vehicle that shares the interchange, not only the car it came off) and it cuts returns (you sell by verified fitment instead of a guess). The catch: some parts have sub-variations inside an interchange group - a connector, a sensor, a bracket - so the number is the starting point, not the final word.
Why it exists
Manufacturers reuse parts across models and model years constantly. A headlight, a transmission, or a door might be identical across three model years and two trim levels, even though the part numbers printed on them differ. Without a common code, you would have to memorize every one of those overlaps.
The interchange number collapses all of that into a single identifier: “these parts are the same for this purpose.”
Why it matters to a seller
Two big reasons:
- Reach. When you list a part by its interchange, it can be found by buyers searching for any of the vehicles that share it - not just the exact car it came off. That widens your pool of buyers dramatically.
- Fewer returns. Most used-parts returns are fitment errors. Selling by verified interchange instead of by guesswork means the part actually fits when it arrives.
The catch
Interchange is powerful but not magic. Some parts have variations within an interchange group (a connector style, a sensor, a bracket) that matter. Good sellers treat interchange as the starting point and confirm the details that trip up buyers.
How reParta handles fitment (honestly)
reParta does not resell the Hollander Interchange or claim its depth. It uses its own US vehicle database of 33,136 configurations - year, make, model, trim, and powertrain - to list each part against the vehicles it fits. That is broad enough to widen reach and cut wrong-fitment returns, while staying honest that on raw interchange depth (about 2 million part applications) Hollander remains the standard.
Who this is not for: if your operation lives on deep Hollander lookups for rare crossover parts, a configuration-level dataset is a complement, not a replacement. If you are a small or mid-size yard selling on eBay and Facebook and you want accurate-enough fitment without the legacy cost, it is built for you - see reParta vs Hollander.
Interchange is the language of used parts. Learning to read it is one of the highest-leverage skills in this business.
Frequently asked questions
What is a Hollander interchange number?
A code that groups auto parts that are interchangeable - parts that fit and function on more than one vehicle, even across different makes, models, or years. If two vehicles share the same interchange number for a part, that one part fits both. It is the auto-recycling industry's de-facto fitment standard, created in the 1930s.
Why does interchange matter to a used-parts seller?
Two reasons: reach (your part is found by buyers of every vehicle that shares the interchange, not just the car it came off) and fewer returns (you sell by verified fitment instead of a guess). The catch is sub-variations inside a group - a connector, sensor, or bracket - so the number is the starting point, not the final word.
Does reParta use the Hollander Interchange?
No. reParta uses its own US vehicle database of 33,136 configurations to match a part to the vehicles it fits. It does not claim the part-level crossover depth of the Hollander Interchange (about 2 million applications); on interchange depth Hollander remains the standard.
