Hobbies & Makers · Web + Mobile
SpoolSense: a 3D print cost calculator and filament tracker
Know what a print costs and what is left on the spool before you quote it.
SpoolSense is a 3D print cost calculator and spool inventory for hobbyists and side-business printer owners. The app would track what remains on every spool and price a print from grams, power, printer wear, failed attempts, and your own hands-on time.
Waitlist Not built yet Updated 5 September 2026
What problem does SpoolSense solve?
A printer pays for itself in stories rather than in figures. The filament came from three suppliers at three prices, half the spools have lost their labels, and the only record of what the last bracket weighed was in a slicer window that got closed. When somebody at work asks what it would cost to print a part, the answer is a shrug and a round number. The gaps show up in two places. The first is a spool that runs out at hour eleven of a fourteen-hour print, because nobody weighed it beforehand and the estimate in your head came from the last time it felt heavy. The second is the first paid order, where the price covered the plastic and nothing else: not the attempt that warped off the bed, not the nozzle, not the two evenings spent clipping supports and sanding a seam. Selling below cost is easy when the cost was never written down.
3D print cost calculator
Filament, electricity, printer wear, failure allowance, and your time, with every formula shown.
Free to use. No account. Nothing you type here is stored.
What would SpoolSense do?
SpoolSense would keep a spool inventory and a cost model beside each other. Every spool gets a record: material, color, brand, price paid, the empty spool weight, and the grams remaining, which you update by weighing it or by logging what the slicer reported. Low stock warnings would arrive before a long print starts rather than after it fails. On the cost side, each print would carry filament, electricity, a share of the printer's purchase price across its expected life, an allowance for failures, and your hands-on time, shown line by line instead of as one total. A quote view would add the margin you set and produce something you can send. Because every figure is yours, changing what you pay per kilogram would reprice everything you make from that material.
How would it work?
- 1Add each spool with its material, price paid, and the empty spool weight from the maker.
- 2Log the grams your slicer reports, or weigh the spool, to keep the remaining filament honest.
- 3Price a print from grams, hours, power draw, printer wear, a failure allowance, and your time.
- 4Add your margin to produce a quote, and watch it reprice when your filament price changes.
Who is it for?
- Hobbyists with a shelf of part-used spools and no idea what is on them.
- Market and online sellers pricing printed parts who have never costed a failed print.
- Makerspace and school volunteers who need a fair charge per gram for members.
How much does a 3D print cost when you work it out by hand?
Your slicer already gives you the two numbers that matter, and it is easy to close the window without reading them. Slice the model, look at the estimate panel, and write down the filament used in grams and the estimated print time in hours. If the display shows meters, switch it to grams: that is a setting, not a calculation, and it saves you doing density and diameter maths for no reason. Filament cost is one line. Divide what you paid for the spool by the grams it held, then multiply by the grams in the print. A spool sold as one kilogram holds a thousand grams of plastic, so the price you paid divided by a thousand gives your cost per gram. Buy on sale and that figure moves, which is why it belongs in a cell rather than in your memory. Electricity is a small line and still worth writing down. Take the printer's average draw in watts, divide by a thousand for kilowatts, then multiply by the print hours and by the price per kilowatt hour on your bill. A plug-in meter left on the machine for a week gives a truer average than the sticker on the power supply, because the heated bed cycles on and off throughout. Then add the three lines that are always missing. Printer wear: purchase price divided by the hours you expect the machine to last, times the hours of this print. Failure allowance: add a share to the subtotal, sized by how many of your recent prints went in the bin rather than by optimism. Your time: minutes on the model, the removal, and the finishing, at a rate you would accept from somebody else. Keep it all in one sheet with a row per print and cost per gram at the top, and every later quote is one multiplication.
What do people use today?
| Option | Good at | The gap |
|---|---|---|
| Free print cost calculators online | One quick answer from grams and hours, with no account and nothing to install. | Nothing remembers your spools, your machine, or your failure rate, so every quote starts from an empty form. |
| A spreadsheet of spools and prices | Free, private, and as detailed as you care to make it, including cost per gram by material. | Updating grams remaining after every print is the chore that quietly stops happening within a fortnight. |
| Slicer estimates on their own | Accurate grams and hours for the exact settings you are about to run, from software already open. | Silent on what the plastic cost, what the machine is wearing through, and what your evening was worth. |
| Print farm and job management software | Queues, several machines, customer jobs, and material tracking for people running a shop. | Priced and shaped for a business with staff, which is heavy going for one printer in a spare room. |
What would it cost?
Free
$0
- The cost calculator on this page
- Up to 3 spools tracked
- Every formula shown with the result
Maker
$4/mo
- Unlimited spools with low stock warnings
- Cost history for every print
- Quotes with the margin you set
- Reprice your catalog when filament prices move
Farm
$12/mo
- Everything in Maker
- Several printers with their own wear rates
- Customer and order records
Prices are proposed. Founding members lock in the lowest price if we build SpoolSense.
Questions people ask
What is a 3D print cost calculator?
A 3D print cost calculator turns the grams of filament and the hours a print takes into money. The full sum adds the price of the plastic, the electricity, a share of the printer's own cost, an allowance for prints that fail, and whatever your hands-on time is worth.
How do I know how much filament is left on a spool?
Weighing beats guessing. Put the spool on a kitchen scale, subtract the empty spool weight the manufacturer publishes, and what remains is plastic. SpoolSense would store that empty weight per brand, so the subtraction happens once and the running figure stays current.
Does electricity really matter in the price?
Electricity is a small line next to filament on a short print, and dropping it is still a habit worth breaking. A long job on a machine with a large heated bed is where it becomes visible, so the tool on this page keeps it on its own row.
What failure allowance should I use?
Your own. Count the prints you threw away last month against the ones you kept, and use that share. A figure copied from a forum describes somebody else's printer, somebody else's filament, and somebody else's bed levelling.
Would it work with my slicer?
Typing two figures from any slicer is the baseline, and that works everywhere. Reading grams and hours automatically from a sliced file is the version worth building, and the file formats people actually use would decide which ones arrive first.
Can I use it to quote paid work?
Quoting is the point of keeping a cost sheet. SpoolSense would take the computed cost, add the margin you set, and produce a quote you can send, with the breakdown shown or hidden depending on the customer.
Does it handle resin printers?
Resin changes the arithmetic: millilitres instead of grams, plus alcohol, gloves, and cure time. The shape of the sum is the same, so resin is plausible later. Filament comes first because the spool problem is what people actually complain about.
When will SpoolSense launch?
There is no date. Enough printer owners joining this list is the entire condition. Until that happens, the cost calculator on this page is free, runs in your browser, and stores nothing.
Where does this stand?
SpoolSense is a proposal, not a product. This page collects demand from search and answer engines. Askwright builds it only if enough people join the waitlist and say they would pay. Read how this works.