How Much Filament Is on A Roll? How Much Is Left on The Spool!

You can make almost anything with a 3D printer. One particularly interesting thing to try is to have a single project that incorporates different types of filament. You could use PLA and PETG to combine the unique properties of each filament into a single print. 

Projects like these are more stimulating than printing something as simple as a name tag holder. While complex projects like these may be a lot more fun, they also present you with harder questions you need to answer to make sure your print turns out as planned.

One of the first questions you will have to answer is how much filament you will need for your project. And how do you keep track of your filament use once you’ve started? These are the main topics we want to cover in this article. But that’s not all we will be looking at.

How Much Filament Is On A Roll?

The quantity of filament on a roll is given as a weight. Most manufacturers supply filament in either 1-kilogram or 3-kilogram rolls. There are smaller quantities such as 500-gram rolls but these are not as common. Filament rolls are sold by the weight of which the 1-kilogram is the most common. While they may be marketed as being 1 or 3 kilograms, in reality, they will either be slightly less or slightly more. 

This is why it’s a good idea to weigh a new roll every time you start a project. This way you have a precise figure for keeping track of your use. We talk about how to keep track of your filament use later in the article. 

You may also want to check out our post Do 3D Printers Generally Come With Filament? (Ender 3 & 5 Examples)

How Long Does a Roll of Filament Last?

A roll of filament can be used over days, weeks, or months. It is difficult to give a definitive estimate of how long it lasts because it depends on several factors. The main factors to consider are:

1. How often do you print? Naturally, if you’re a casual user your filament will last longer than for a heavy user. A heavy user printing between 40 to 120 hours a week would likely finish their filament in less than a month.
2. What do you print? Complex or large prints will use up more filament. For example, if you’re printing models that use over 250 grams of filament, you would have 3 or 4 runs before you ran out of filament.

Working with weights can be a little complicated. This is why some manufacturers also supply the length of the filament roll. Unfortunately, not all filament manufacturers do this. So, what do you do if you need to know the length of the filament and you don’t have it?

How Do You Find The Length Of A Filament?

Three values are needed to calculate the length of a filament. These are the weight, diameter, and density of the filament.

To obtain the length first divide the weight of the filament by its density. Then multiply the result by the cross-sectional area of the filament

Length = (Weight/Denity) X cross-sectional area

As we’ve already discussed, you should weigh your filament beforehand. Filament comes in diameters of either 1.75 or 2.85mm. It is from the diameter that we get the cross-sectional area. 

Density varies depending on the type of filament. You may have to check with the manufacturer but generally, these are the densities you should expect for the most common types of filaments. 

We also highly recommend that you check out our post What Happens When Filament Runs Out? How To Save Your Print!

What Is the Length of 1 Kg of Pla Filament?

1 kilogram of PLA filament with a diameter of 1.75mm has a length of 370 meters. A kilogram with a diameter of 2.85mm has a length of 3,278 meters.  

How Do I Know If I Have Enough Filament For Printing?

Filament requirements for a print depend on the specifics of the print chiefly the size and complexity. The larger or more complex the print is, the more filament will be required. The most accurate way to determine how much filament is required for a print is with slicing software. 

Projects vary. A simple project like a name tag holder will differ from something more complex like a replica model of Darth Vader’s helmet for example.

1. The helmet is much larger so will require more layers than the name tag holder.
2. The name tag holder is a relatively “flat” 3D object compared to the helmet which has more edges and angles. Even at the same size, you would highly likely use more filament for the helmet due to its complexity.

In the good old days of 3D printing, much of the calculation for how much filament you needed for a project was through guesswork. Fortunately, the introduction of slicers has taken that burdensome task away which makes printing much more fun and less prone to disasters!

Use a slicer

Slicers take the 3D digital model from your prototyping software and turn that into information your printer uses to create a physical model. But that’s not all a printer can do. Slicers also tell you: 

1. The estimated length of filament required.
2. The estimated time it will take to complete.
3. The cost of the filament required.

On a side note, Check out How Accurate Is Cura Filament & Print Estimates? Settings Explained!

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For more on this, check out our post How Much Filament Do You Have Left? Tips & Tricks Listed!

How Do I Track My Filament Usage?

The simplest way is if the filament has its lengths printed on the side. There is also the option of unrolling and measuring if it is a very short roll. For a longer roll, weighing is a better option. There is also the option of using a slicer plugin.

Some printers do have filament tracking built-in. Combined with NFC tags you can use them to track your use. NFC tags work like barcodes relaying information on your filament including the manufacturer, date of manufacture, etc. 

You can either buy your tags or buy filament that comes with NFC tags. If the tags and your printer are compatible, this makes tracking easier. Source

You can also track by weight. As you use your filament, you can weigh it and subtract that from the full weight to find out how much you have used. Make sure to exclude the weight of the spool from your calculations.

The final and possibly easiest option is to use a plugin with your slicer software if there are no built-in solutions.