Filament cost calculator

Work out the cost of filament per gram, and the cost of the material in one print. Type in what the spool cost and what it weighs, then the weight of the part from your slicer: the calculator adds purge and failed prints, and works for PLA, PETG, ABS or anything else sold on a spool.

The plastic, not the plastic plus the reel.

What the slicer says the part weighs.

Purge towers, brims, and the odd failed print.

This print costs $3.15 $3.00 for the part + $0.15 for 5% waste
Cost per gram $0.0263 what every gram of this spool costs you
Prints per spool 7 before you open the next one
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From filament cost to a profitable print

3D print cost calculator

What a print costs you in filament, machine time and your own hours - and what to charge for it.

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3D printer hourly rate calculator

What an hour of your printer costs once it is wearing out, drawing power and being serviced.

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Turning that cost into a price is a question of its own: What to charge for a 3D print.

Buying filament for more than one printer? Starting a 3D print farm: the first ten decisions covers how much to stock and how to keep it dry.

Keeping every spool priced as stock, not just this one? Which software a 3D print shop needs, and in what order maps the software, and says when a spreadsheet is enough.

A worked example

The figures the calculator opens on, worked by hand: a $25 spool holding 1000 g of filament, and a part your slicer weighs at 120 g.

  1. Price per gram: $25 ÷ 1000 g = $0.025 a gram.
  2. The material in the part: 120 g × $0.025 = $3.00.
  3. Purge and failures: $3.00 plus 5% = $3.15. That is the figure in the calculator, and $0.0263 a gram once the waste is counted.

The same part on a multi-colour printer

Same spool, same 120 g part, but every colour change purges filament through the nozzle.

  1. Purge at 35%: $3.00 plus 35% = $4.05.
  2. That is $0.90 more than at 5%, for the same part off the same spool.
  3. The spool now makes 6 of these rather than 7.

A failed print and its reprint

The same part fails half way through, after 60 g, and is printed again.

  1. The failure: 60 g × $0.025 = $1.50.
  2. The reprint: 120 g × $0.025 = $3.00.
  3. One part delivered, 180 g of filament: $4.50 before purge, 1.5 times the plastic in it.
  4. Over twenty prints, one failure like this is 60 g in 2400 g, or 2.5%. That is what the waste allowance is for.

Filament is one line of what a print costs. The 3D print cost calculator adds print time, your own hours, the printer’s wear and your margin, and LayerFlow3D works all of it out on every order from your own spools and printers.

What each number means

Spool price

What you paid, including delivery if you paid it. A spool that cost $25 and $6 to ship costs $31.

Spool weight

The plastic, not the plastic plus the reel. A "1 kg spool" is a kilo of filament on a reel that weighs a couple of hundred grams more.

Filament in the part

What the slicer says the part weighs. Supports and rafts count - they came off the same spool.

Purge and waste allowance

Purge towers, brims, skirts and the odd failed print. Five per cent is a careful shop with a single-material printer; a multi-colour machine purging between every layer change is far higher.

Guides that use this calculator

Filament inventory that does not drift

Why spool counts stop matching reality, and the small number of habits that keep filament stock honest without anybody weighing everything on a Sunday.

Read it →

Questions people ask

How do I work out filament cost per gram?

Divide the spool price by the grams of plastic on it, then add your waste allowance. A $25 spool holding 1000 g is 2.5 cents a gram before waste, and about 2.6 cents after a 5% allowance.

Does a 1 kg spool really hold 1 kg?

The filament does. The reel it is wound on does not count, so weigh an empty reel of the same brand once and subtract it if you are working backwards from a kitchen scale.

Why add a waste allowance at all?

Because a spool does not all become parts. Purge towers, brims, skirts and failed prints come off the same spool, and a shop that prices at the bare part weight is quietly paying for all of it.

Is cheap filament worth it?

Sometimes. Work out the cost per gram including the failures it causes: a spool that is 20% cheaper and fails one print in ten is not cheaper.

How much waste should I allow for multi-colour prints?

Far more than for one colour, and it depends on the plate. Every colour change purges filament through the nozzle, and on a small part with many changes the purge can outweigh the part. Your slicer reports what goes to purge for each job: take that over a few typical jobs as your allowance, and keep 5% for single-colour work.

Should shipping go into the spool price?

Yes, if you paid it. A spool that cost $25 and $6 to deliver costs $31, and every gram on it carries its share of the delivery. Where one delivery brought several spools, split it across them.

Does it work for PETG, ABS, TPU and other materials?

Yes. The sum is the same for anything sold by weight on a spool: what it cost, divided by the grams of filament on it. What changes between materials is the price and the waste - a material that is harder to print deserves a larger allowance than PLA.

Can I track this per spool rather than per brand?

That is what LayerFlow3D does. Each spool is tracked by weight as it is used, so an order shows what that particular spool cost you.

Know what every spool on the shelf is worth

LayerFlow3D tracks each spool by weight as it is used, so material cost on an order is what that spool actually cost you - not an average, and not a guess.

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