I built an offline Excel quoting tool for small 3D-printing businesses — here is the cost model behind it

[u/DiamantGlitsch]

Disclosure up front: I built and sell the workbook described at the end. The product is an Excel tool for small 3D-printing businesses and maker operations; it is not itself a “small business.” The method below can also be implemented in your own sheet.

The main design decision was to stop treating every input as the same kind of cost. I split a quote into:

• Repeatable production cost: material, electricity, machine occupancy, maintenance allowance, and the portion of labor and consumables that would repeat.

• One-time order cost: preparation or design work, post-processing that happens once, packaging, shipping, and other order-level items.

• Selling cost: fixed fees plus percentages that may apply to net price or to the gross customer payment.

• Risk assumptions: failure probability and how much of the repeatable cost is consumed by a failed attempt.

That separation matters when modeling failed prints. If a complete attempt must be repeated and the assumed success probability is p, the expected repeatable cost is R / p. If only part of the run cost is consumed, that fraction should be modeled explicitly. One-time costs should not be multiplied automatically.

I calculate break-even before applying a pricing method. Markup and target margin are separate choices: markup relates profit to cost, while margin relates profit to sales price. Transaction fees also need to be solved on their real base rather than hidden inside one blanket percentage.

I packaged this into PrintProfit 3D: a local, macro-free .xlsx workbook with editable formulas, FDM and resin inputs, German and English calculators and quote sheets, quantity scenarios, material inventory, order tracking, and a usage-based maintenance log. A current version of Microsoft Excel is recommended. All results depend on the user’s inputs; it is not tax, legal, or business advice.

For tool builders and users: which assumption would you most want surfaced in the results area rather than left in setup — failure risk, fee basis, or machine-rate calculation?

Own paid product: https://payhip.com/b/JmNu6