Guide
How Long Does a Spool of Filament Last?
Two different questions live inside this one: how many objects a kilogram makes, and how long a spool stays good sitting on a shelf. The answers are 'more than you think' and 'it depends on the plastic'.
By Scooter M. · Published · Last reviewed
How this page is funded: the buy links below are affiliate links. If you buy through one we earn a commission, at no extra cost to you. It does not change the order of the picks or a word of what we say about them. Full disclosure.
Printers we claim to have tested: 0. Everyone in this category says they tested twenty machines. We have not tested any, and we would rather say so. What we did instead is on this page: the manufacturer’s own published specification for every pick, cited and dated; the arithmetic on what it costs to run, with the inputs shown; a live price rather than a remembered one; and a plain answer on who should skip each machine.
The short answer
Twenty to thirty useful objects from a kilogram, and roughly a year of shelf life sealed. A 1 kg spool goes further than almost every beginner expects, because most things people actually print weigh tens of grams. Its shelf life is not about age — it is about how much air it has been exposed to.
How many objects, honestly
A kilogram is a thousand grams. Cable clips are five to twenty grams each. Phone stands are twenty to fifty. A desk organizer is eighty to two hundred. Do that arithmetic across a realistic mix of what a beginner prints and you land at twenty to thirty objects per spool, with plenty of room either side depending on what you make.
The exceptions are the big ones: a large vase, a helmet section, a full storage crate. Those can take a third of a spool each, and if that is your intended use, plan on more filament and fewer objects.
Your slicer removes all guesswork here — it reports the exact grams for any model before you print. The full per-print arithmetic is on what filament costs per print.
How long it keeps
Filament does not really expire in the way food does. What happens is that it absorbs water from the air, and water is what causes popping, stringing and weak layers. So “how long does it last” is really “how much air has it seen.”
Practical guidance rather than a manufacturer specification. Humidity where you live changes all of these substantially.
| Condition | PLA | PETG |
|---|---|---|
| Sealed in its vacuum bag with desiccant | A year or more | A year or more |
| Airtight box with fresh desiccant | Months | Months |
| Open on the printer, dry room | Weeks | Days to weeks |
| Open on the printer, humid room | Weeks, degrading | Days |
| Garage or basement, unsealed | Avoid entirely | Avoid entirely |
Which is why our practical advice is not “buy less” but “buy two spools and store them properly.” Sealed filament keeps essentially indefinitely. Storage and drying covers how, including the free version.
When to buy the next spool
Sooner than you think, for a reason that is not about running out. Nothing is more annoying than a print that fails at hour six because the spool ended, and most beginner machines below the top band do not publish a filament run-out sensor. Having a second spool of the same color turns that from a ruined print into a pause.
The other reason: one color is boring by week three. Two spools in different colors is a better first purchase than two of the same, and it is cheap insurance against both problems at once.
Weighing a partly used spool
A trick worth knowing: put the spool on a kitchen scale and subtract the empty spool weight, which most manufacturers print on the spool or publish. What is left is how much filament you have, which tells you instantly whether a 300 g print is going to finish.
This is far more reliable than looking at how full the spool appears. Filament is wound tightly and the last two hundred grams look like far less than that.
What we would buy for this
Chosen from the same registry as our roundups, on the manufacturer’s own published figures and a live price.
Overture PLA
Overture · Your first spool, and your tenth
The default answer to 'what filament should I buy'. A tight published diameter tolerance, a conventional temperature range every printer profile already expects, and it is sold everywhere. Nothing about it is exciting, which is the point.
#ad We do not hold a current price for this product, so we do not show one. How we make money.
What it actually is
PLA is the plastic beginners should print. It is stiff, it needs no enclosure, it barely smells, and it sticks to a plate at low temperatures. This is a mainstream 1 kg spool of it.
What the manufacturer states
| Figure | Value | Source |
|---|---|---|
| Diameter | 1.75 mm | Overture published product specification |
| Dimensional accuracy | +/- 0.02 mm | Overture published product specification |
| Spool weight | 1 kg (2.2 lb) | Overture published product specification |
| Recommended nozzle temperature | 190 - 220 C | Overture published product specification |
| Recommended bed temperature | 25 - 60 C | Overture published product specification |
| Packaging | Dried before packing and vacuum sealed | Overture published product specification |
Read from Overture, PLA filament product page on 2026-09-01. Where a manufacturer does not publish a figure, there is no row for it here.
What is good about it
- +/- 0.02 mm published tolerance, which is as tight as mainstream PLA is quoted
- 190 - 220 C is squarely inside every stock PLA profile you will meet
- A 25 - 60 C bed range means it will stick even on an unheated or barely warm plate
- Vacuum sealed with desiccant, so a spool bought in advance is still dry when it arrives
What is not
- PLA softens in a hot car or a sunny window — this is a property of the material, not the brand
- Not the cheapest per kilogram once you start printing seriously
- Color consistency between batches of any budget filament is a real thing
- No filament is a fix for a machine that is not leveled
Skip this one if
Skip it if the part you are making will live outdoors or in a car. That is a PETG job, not a PLA one, and no PLA brand changes that.
What we cannot tell you
We have not printed this filament. Batch-to-batch color consistency and how it behaves after a year in a cupboard are things only repeated use reveals.
How it scored for a beginner
- Ease for a beginner9.5
- Published tolerance9.5
- Availability9.5
- Value per kilogram8.0
Beginner fit 9.0 / 10. That is our editorial read of how well this suits someone buying their first printer, taken off the published specifications — not a test result, and not a verdict on absolute quality. It is deliberately not marked up as a rating in this page’s structured data. How we pick.
SUNLU FilaDryer S4
SUNLU · Filament that has been open more than a few weeks
The accessory that fixes a failure most beginners misdiagnose. Filament absorbs water from the air; wet filament pops, strings and prints badly, and no amount of leveling fixes it. Four spools at once and you can print straight out of the box.
#ad We do not hold a current price for this product, so we do not show one. How we make money.
What it actually is
A heated box that drives moisture out of filament and then keeps it dry while you print from it. Plastics like PETG and nylon pull water out of ordinary room air within days, and water in the filament turns to steam in the nozzle.
What the manufacturer states
| Figure | Value | Source |
|---|---|---|
| Capacity | 4 x 1 kg spools | SUNLU FilaDryer S4 published specification |
| Temperature range | 35 - 70 C | SUNLU FilaDryer S4 published specification |
| Heater | 350 W PTC heater | SUNLU FilaDryer S4 published specification |
| Filament diameters supported | 1.75 mm, 2.85 mm, 3.0 mm | SUNLU FilaDryer S4 published specification |
Read from SUNLU, FilaDryer S4 product page on 2026-09-01. Where a manufacturer does not publish a figure, there is no row for it here.
What is good about it
- Four spools at once, which is the difference between drying filament and having dry filament
- 35 - 70 C covers PLA at the low end and nylon at the high end
- You can feed the printer directly from the box, so filament stays dry mid-print
- Fixes a whole class of print failures that look like machine problems
What is not
- A 350 W heater is more power than most printers here draw
- It is a large box that needs somewhere to live next to the printer
- Nothing about it helps on a fresh, sealed, dry spool
- Sealed boxes with desiccant do most of the same job for less money if you are only storing
Skip this one if
Skip it on day one. Your first spool arrives vacuum sealed and dry, and a dryer solves a problem you will not have for weeks. Buy it when a spool that used to print well starts popping and stringing.
What we cannot tell you
We have not used this dryer. How long a spool actually stays dry in a humid room, and how accurate the displayed temperature is, need measurement we have not done.
How it scored for a beginner
- Ease for a beginner9.0
- Fixes a real failure9.5
- Availability8.5
- Value7.5
Beginner fit 8.5 / 10. That is our editorial read of how well this suits someone buying their first printer, taken off the published specifications — not a test result, and not a verdict on absolute quality. It is deliberately not marked up as a rating in this page’s structured data. How we pick.
How these were picked
We have not printed on these machines and we do not pretend to have. What we did was read each manufacturer’s own specification page, take their stated build volume, temperatures and speeds, check that every pick genuinely fits the job in this page’s title, confirm it is still being sold, and pull a live price rather than a remembered one. Every figure names the source it came from, so you can check it yourself in about a minute.
How we pick sets out the full method, including what would change a ranking.
Questions people actually ask
+−How many prints does 1 kg of filament make?
Twenty to thirty typical desk-sized objects for most beginners. Small items like clips run into the dozens; a large vase or helmet section can take a third of a spool by itself.
+−Does 3D printer filament expire?
Not by age. It degrades by absorbing moisture from the air, so a spool sealed in its vacuum bag with desiccant keeps essentially indefinitely, while an open spool in a humid room can misbehave within weeks — days for PETG.
+−How do I know how much filament is left on a spool?
Weigh it on a kitchen scale and subtract the empty spool weight, which manufacturers usually print on the spool. Judging by eye is unreliable: filament is wound tightly and the last couple of hundred grams looks like much less.