Extrusion Multiplier Calculator

The extrusion multiplier (also known as flow rate or flow multiplier) is a setting in your 3D printer slicer software that adjusts how much filament is extruded during printing. It's a value that tells the printer how much material to push through the nozzle compared to the default amount. This setting helps improve print accuracy by fixing over-extrusion or under-extrusion issues.

For example, if your prints are looking too thick or thin, or the layers aren’t bonding correctly, adjusting the extrusion multiplier can fix these problems. It’s a key factor in getting high-quality prints.

How to Use the Extrusion Multiplier Calculator

We’ve developed a simple online extrusion multiplier calculator that helps you find the correct multiplier in seconds. No guesswork, no complex steps—just accurate results to improve your 3D prints.

Here’s how to use it:

1. Print a single-wall calibration cube using your current settings.
2. Measure the actual wall thickness with a digital caliper.
3. Enter the expected wall thickness (as set in your slicer).
4. Enter the measured wall thickness (from your printed object).
5. Hit Calculate.

The calculator will instantly show the correct extrusion multiplier you should use in your slicer.

Formula to Calculate Extrusion Multiplier

To calculate the extrusion multiplier, use this simple formula:

Extrusion Multiplier = Expected Wall Thickness / Measured Wall Thickness

Let’s say your slicer is set to make a wall 0.40 mm thick, but your printed wall measures 0.44 mm. Then:

Extrusion Multiplier = 0.40 / 0.44 = 0.909

So, you should set your extrusion multiplier to 0.91 in your slicer.

Is Flow Ratio the Same as Extrusion Multiplier?

Yes, flow ratio and extrusion multiplier mean the same thing. Both are used to adjust the amount of filament your printer extrudes. In some slicers like Cura, the setting is called Flow (usually set as a percentage like 100%). In others like PrusaSlicer or Simplify3D, it's called Extrusion Multiplier.

Just remember:

Flow (%) = Extrusion Multiplier × 100

So, if your extrusion multiplier is 0.95, then your flow rate should be set to 95%.

What is Extrusion Multiplier in Cura?

In Cura, the extrusion multiplier is called Flow and you can find it under the Material settings. It’s usually set to 100% by default, which means the printer will extrude the amount calculated by the slicer without any change.

To adjust it:

• Open Cura
• Go to “Material” settings
• Find the Flow setting
• Enter the new percentage based on your extrusion multiplier calculation

For example, if your extrusion multiplier is 0.91, then set the Flow to 91%.

Final Verdict

Getting the extrusion multiplier right is one of the easiest ways to improve your 3D print quality. With our extrusion multiplier calculator, you no longer have to guess or waste filament. Just measure, calculate, and update your slicer. Whether you’re using Cura, PrusaSlicer, or Simplify3D, this method works the same.

Correct extrusion settings help fix layer issues, prevent blobs or gaps, and give your prints a professional finish. Bookmark this page and use the calculator every time you change filaments or tweak your printer.

FAQs

What’s the ideal extrusion multiplier?

It depends on your printer and filament. Most values fall between 0.90 to 1.10. Use the calculator to find your exact value.

Should I use the same multiplier for all filaments?

No, different filaments may need different settings due to differences in material density and flow.

How often should I recalibrate?

You should recalibrate every time you change filament brands or types or after making mechanical changes to your printer.

Can incorrect multiplier damage prints?

Yes, too high can cause over-extrusion, blobs, and layer shifting. Too low causes weak prints and gaps.

Is this calculator accurate?

Yes, if you measure correctly and print a clean single-wall test object, the result is very reliable.