SERVICE VAN STOCK OPTIMIZER · RUNS IN YOUR BROWSER · NOTHING UPLOADED

Which parts should the van carry?

Paste your parts list and what your past jobs used. The tool picks the stock that finishes the most jobs on the first visit for the money and shelf space you have, counting parts that have to travel together, and puts a price on every return trip it prevents. For up to 20 part units the answer is exact. It then tests itself on jobs it has not seen, and compares the result with what your van carries now.

Your jobs and costs never leave this browser tab. Planning aid, not legal, tax, or financial advice. It knows nothing about codes, licensing or regulated parts.

Your parts and jobs

Copy the parts from your price list or a spreadsheet; any part named in a job but missing from the catalog gets the default cost below. List jobs oldest first: the self-test scores the newest 30% as jobs the list has not seen. Lines starting with # are ignored. Use the same spelling of a part in both boxes.

Paste your parts and past jobs, then click the button.

How it is calculated

A job is finished on the first visit only if every part it used is on the van in the quantity it used. Each unit of a part is one item, so two capacitors are two items. For a stock list S the tool values return-trip cost × jobs per year × (share of past jobs the list completes) − carrying cost × money tied up in S, and rejects lists over your budget or slots. Return trips avoided are counted against a van that carries nothing, so jobs that used no parts are not credited. Method: up to 20 part units, every list is checked using a subset-sum count of the jobs each list completes, so the best list is proven best for your history. Beyond 20, every list of the 20 most-used units is checked and a greedy search with pair-adds and swaps runs over all units; the better one wins and the page says it is not proven.

Checks on itself: the list is refit on the oldest 70% of jobs and scored on the newest 30%, next to a list of simply the most-used parts for the same spend; a resampling of your history (400 seeded draws) gives an 80% range for the completion rate. Not modelled: part substitutions and kits, supplier lead times and restocking, seasonality, which technician is on the job, parts used across several visits, price changes, regulated or licensed items, and any benefit beyond the return-trip cost you enter (lost customers, reviews). Unverified: the exact solver is checked against brute-force enumeration on random problems and the heuristic against limits and baselines, on invented data, not a real shop's history.

Common questions

Which parts should a service van carry?

The ones that let the most jobs finish on the first visit for the money and space you have. Ranking parts by how often they are used is a decent start, but a job only finishes if every part it needs is on the van, so parts that travel together have to be judged together. This tool takes your past jobs, tries the stock lists that fit your budget and shelf space, and picks the list with the highest value, which for up to 20 distinct part units is proven best for your history.

How do I cut return trips to the supply house?

Put a dollar figure on a return trip (the technician's time, the drive, the delayed customer), list what your past jobs used, and let the tool price each part against the callbacks it prevents. The answer shows which parts are worth their shelf space, which are not, and what the next part you do not carry would save.

How much inventory should a technician's van hold?

There is no universal figure. The tool draws a curve of first-visit completion against dollars tied up, so you can see where extra stock stops paying. It also lets you set a hard budget and a slot limit, and shows how the best list changes if a return trip costs half or double what you estimated.

Is the stock list exact or a guess?

With up to 20 distinct part units (a part needed twice counts as two units) every combination is checked, so no list scores higher on your history. With more, it checks every combination of the 20 most-used units and also runs a greedy search with swaps, and keeps the better one; the page says which method ran.

How do I know it will work on next month's jobs?

It tests itself: it fits the list on the older 70% of your history and scores it on the newest 30% it has not seen, compares that with simply stocking the most-used parts for the same spend, and gives a range from resampling your history. Expect the out-of-sample rate to be a little lower than the in-sample rate; a large gap means you need more history.

What if my van already carries a stock list?

Paste it and the tool scores it the same way: its first-visit completion, its yearly net value, and the money tied up in parts your history never used or in more units than any job needed. Then it shows the difference against the recommended list.

Is my job history uploaded anywhere?

No. Parts, costs and job lists are read and solved in this browser tab. Nothing is sent to a server, there are no accounts or cookies, and the tool does not store your data. It works offline once the page has loaded.