What counts as a 'failed' print?

Whatever you had to throw away or reprint. Complete detachments from the bed, spaghetti, failed supports, layer shifts, warping that ruined the part. Partial successes that you salvaged don't count as failures, but the wasted filament below the salvage point kinda does. Track it however feels honest.

What's a good failure rate?

Under 5% means your printer is well-tuned and you're printing things you have experience with. 5 to 10% is typical hobbyist territory. 10 to 20% suggests something's off (bed adhesion, filament moisture, first-layer calibration). Over 20% usually means a mechanical or calibration issue worth investigating.

How do I actually track this?

Simplest: a notes app or spreadsheet with one line per print, marked success or fail. Most slicers log print history. For a month, count them up and plug them in here.

Does this include multi-color swap failures?

Not specifically. If an AMS swap caused a clog and killed the print, count it as a failure. The dedicated AMS purge waste calculator covers the non-failure waste (intentional purge per swap) in a later update.

Is 0% failure realistic?

No. Even commercial print farms run at around 2 to 4% failure. Hobbyists aiming for 0% will drive themselves crazy. Aim for single digits consistently and call it a win.

Print Failure Rate Calculator

Track how often your prints fail, and see how much filament and money that costs. Compare your rate to hobbyist benchmarks so you know whether you have a tuning problem or you're doing fine.

How this works

Failure rate is simply failed prints divided by total prints, expressed as a percent. The benchmark bands come from community consensus on forums and Discord servers: under 5% is excellent, 5 to 10% is typical for hobbyists, 10 to 20% usually points at a specific tuning or hardware issue, and anything above 20% warrants serious investigation.

Tracking this month over month is more useful than a single snapshot. A spike after you changed filament brands tells you something. A steady 7% tells you to keep your process and move on with your life.

The math behind the cost number

Failure rate by itself is just a number. The interesting part is what it's actually costing you. Two formulas:

failure_rate = failed_prints / total_prints

attempts_needed = 1 / (1 - failure_rate)

The second one is the hidden cost. At 10% failure rate, you need 1.11 attempts on average for every one successful print. That means every successful print is carrying 11% extra material cost and 11% extra time on average. At 25% failure, you're paying for 1.33 attempts per success, meaning every "good" print effectively cost you 33% more than the calculator told you.

Worked example. Failure rate of 8%, 200 g print at $22/kg filament: each successful copy of that print effectively used 200 / (1 - 0.08) = 217 g of material, costing $4.78 instead of the $4.40 the filament cost calculator would say.

The 12 most common failure modes, ranked

When your failure rate creeps up, walk this list top to bottom. The top items account for most failures across community surveys.

First layer adhesion failure. The single biggest cause. Bed level, bed cleanliness, first layer height, first layer temperature, and bed surface all contribute. Clean the bed with isopropyl alcohol, re-level.
Detachment mid-print (warping). Especially ABS, ASA, and large flat PETG parts. Enclosure helps, brim helps, slowing the cooling fan helps.
Layer shifts. Belt tension, motor current, sudden moves. More common on belt printers running fast.
Spaghetti from wet filament. Bubbles in the nozzle make extrusion unreliable. Dry the filament.
Clogged nozzle. Slow extrusion, under-extrusion patterns, missed layers. Cold pull or replace nozzle.
Bridging or overhang failure. Model issue or cooling issue. Slow first bridge layer to 30% speed.
Support detachment. Often happens on tall thin supports. Increase support density or switch to tree supports.
Filament tangle. Extruder pulls until something snaps. Inspect spools when mounting.
Power loss. Some printers can resume, many cannot. UPS for long expensive prints if power is unstable.
Slicer settings wrong. Wrong filament profile, wrong nozzle size in slicer vs printer. Always verify before hitting print.
AMS feed jam. Filament binds in the bowden tube during a swap. Clean the AMS, check filament diameter consistency.
Extruder gear slipping. Worn gear, weak spring, or material too soft (TPU). Tighten or replace.

What different failure rates actually mean

0 to 4%. Excellent. You've dialed your printer in and you're printing things you have experience with. This is the realistic ceiling for hobbyists.
5 to 10%. Normal. Most hobbyists live here. Mostly clean prints with the occasional bed adhesion or filament issue.
10 to 20%. Something specific is off. Usually filament moisture, bed adhesion, or a calibration drift. Walk the failure mode list above.
20 to 35%. Mechanical or systemic issue. Belt tension, hotend, extruder, firmware bug, or you're pushing the printer way past its tuned envelope.
Over 35%. Stop printing and troubleshoot. You're burning filament for no reason.

The print farm benchmark

Commercial print farms track failure obsessively because every point of failure rate compounds across hundreds of prints per week. Real numbers:

Top-tier production print farm: 1 to 3% failure rate
Etsy seller print farm: 3 to 7% failure rate
Hobbyist with experience and dialed printer: 4 to 8%
Average hobbyist: 8 to 15%

If you're selling prints, every percent of failure rate is margin you're leaving on the table. Worth investing time in tuning before you scale up.

Frequently asked

What counts as a 'failed' print?: Whatever you had to throw away or reprint. Complete detachments from the bed, spaghetti, failed supports, layer shifts, warping that ruined the part. Partial successes that you salvaged don't count as failures, but the wasted filament below the salvage point kinda does. Track it however feels honest.
What's a good failure rate?: Under 5% means your printer is well-tuned and you're printing things you have experience with. 5 to 10% is typical hobbyist territory. 10 to 20% suggests something's off (bed adhesion, filament moisture, first-layer calibration). Over 20% usually means a mechanical or calibration issue worth investigating.
How do I actually track this?: Simplest: a notes app or spreadsheet with one line per print, marked success or fail. Most slicers log print history. For a month, count them up and plug them in here.
Does this include multi-color swap failures?: Not specifically. If an AMS swap caused a clog and killed the print, count it as a failure. The dedicated AMS purge waste calculator covers the non-failure waste (intentional purge per swap) in a later update.
Is 0% failure realistic?: No. Even commercial print farms run at around 2 to 4% failure. Hobbyists aiming for 0% will drive themselves crazy. Aim for single digits consistently and call it a win.