Klipper Pressure Advance vs No Pressure Advance: Quick Comparison

Pressure advance is Klipper’s way of compensating for the lag between your extruder gears and what actually comes out of the nozzle.
Instead of pushing filament at a constant rate, Klipper slightly boosts or reduces flow ahead of time as the toolhead speeds up and slows down.

The most visible differences show up at corners and during travel moves. Below is a simple comparison to set expectations before you tune anything.

Pressure advance does not fix every quality issue, and it will not magically hide poor bed leveling or wrong flow rate.
It only works properly if your basics are already dialed in, which is why we treat it as a later step in the
3D printer calibration guide.

When You Should Use Klipper Pressure Advance

If you run Klipper, you should almost always tune pressure advance.
It is one of the key reasons people move to Klipper in the first place, right next to input shaping and flexible macros.

Typical signs you need pressure advance

• Bulged corners on calibration cubes, especially on the side where the seam runs
• Blobs right after the toolhead slows for a sharp turn
• Visible under extrusion just after corners, as if the wall dips in slightly
• Stringing between towers even after lowering temperature and optimizing retraction
• Quality that falls apart as soon as you raise accelerations to take advantage of Klipper

In our lab tests on common bedslingers and CoreXY printers, tuning pressure advance typically made more difference to corner sharpness than changing nozzles or swapping slicers.
Once pressure advance was dialed in, we could push input shaping and higher accelerations confidently, as covered in the
Klipper input shaping guide.

When pressure advance will not help much

There are cases where you will see limited improvement:

• Massive over extrusion or incorrect steps per mm that have not been calibrated yet
• Bed adhesion problems, elephant foot and warped corners caused by cooling or warping
• Very low speed decorative prints where accelerations are minimal
• Mechanical issues such as loose pulleys, bent rods or a shifting hotend

If prints still look rough with very conservative speeds, go back to the basics in
Top 3D printing mistakes to avoid and fix extrusion and mechanics before spending time on pressure advance.

How Klipper Pressure Advance Works (Plain Language)

Inside your extruder system there is always some elasticity.
Filament can compress inside a Bowden tube, bend slightly between gears and nozzle, and the stepper motor itself behaves like a small spring under load.
When your toolhead accelerates, some of the extra filament motion goes into building pressure instead of leaving the nozzle.
When it slows down, that stored pressure keeps pushing filament out even if the gears already slowed.

Pressure advance asks Klipper to change the extrusion rate based on acceleration so that the nozzle pressure stays more constant.
Klipper feeds a bit more filament when it detects acceleration, and it feeds less filament as the toolhead decelerates.
The end result is that the actual flow of plastic matches the requested line width more closely even when speeds and accelerations change rapidly.

In firmware terms, Klipper uses a parameter called pressure_advance on the extruder.
The value represents how far in advance extrusion needs to change relative to toolhead acceleration.
Larger values mean the system is more elastic, which is why Bowden setups usually need higher numbers than compact direct drive extruders.

Direct drive vs Bowden expectations

Every printer is unique, and you should tune your own machine, but in our testing and manufacturer documentation a few patterns show up:

• Compact direct drive systems on PLA often land in a relatively low range for pressure advance.
• Bowden systems with a long tube need noticeably higher values.
• Softer filaments like TPU or very flexible PETG may require higher pressure advance than stiff PLA because they compress more.

The goal is not to match someone else’s number exactly.
The goal is to find the lowest value that removes corner bulges without creating dimples or under extruded sections after corners.

Preparation: What You Need Before Tuning

Pressure advance tuning only works well if the rest of your setup is reasonably configured.
Before you start, make sure you have:

• A printer that is already printing solid calibration cubes without layer shifts
• Extrusion steps and flow rate tuned as described in the
  3D printer calibration guide
• Bed leveled and first layer reliable
• Input shaping either disabled for the test, or already tuned and stable
• Retraction settings roughly dialed in for the filament you will use

Choose one filament type and one nozzle size for each tuning run.
Most users start with 0.4 mm PLA at a comfortable speed.
If you frequently swap nozzles or materials there is nothing wrong with keeping a small note of your favorite pressure advance values per combo.

Step-by-Step: Tuning Pressure Advance in Klipper

The most reliable method for Klipper is to print a dedicated test and let the firmware sweep through several pressure advance values in a single object.
We follow the approach from the official Klipper documentation and combine it with real world checks you can do at a glance.

1. Configure your slicer for the test

You can use your preferred slicer for this test as long as you keep settings simple and predictable:

• Layer height around 75 percent of nozzle diameter (for a 0.4 mm nozzle, use 0.28 to 0.30 mm)
• Infill set to 0 percent so the test is a hollow tower or cube
• Perimeter speeds set relatively high to exaggerate the effect, around 80 to 100 mm per second
• Disable coasting, pressure or linear advance features inside the slicer itself
• Use a consistent temperature that you already know produces okay quality

Many Klipper users use the square tower model from the official docs or a similar sharp corner tower.
Whichever model you choose, the goal is to get vertical walls with repeated 90 degree corners, since those are where you will see the difference.

2. Set Klipper test limits

Open your Klipper web interface and run a command to limit corner velocity and acceleration during the test, for example:

SET_VELOCITY_LIMIT SQUARE_CORNER_VELOCITY=1 ACCEL=500

This slows corners enough that the pressure advance effect becomes very visible without risking skipped steps.

3. Start a tuning tower for pressure advance

Next you want Klipper to vary the pressure advance value as the tower grows so you can see a gradient of behavior from bottom to top.

For a direct drive extruder, a typical starting command looks like:

TUNING_TOWER COMMAND=SET_PRESSURE_ADVANCE PARAMETER=ADVANCE START=0 FACTOR=0.005

For a Bowden setup, the step between values is usually larger:

TUNING_TOWER COMMAND=SET_PRESSURE_ADVANCE PARAMETER=ADVANCE START=0 FACTOR=0.020

After you enter the command, start the test print from your slicer.
As the printer works through layers, Klipper will automatically increase the pressure advance value.
You do not need to pause or edit g-code manually for each value.

4. Watch the tower and note the sweet spot

Once the test finishes, let the tower fully cool and then inspect it in good light. Look closely at the outer corners:

• At the bottom, where pressure advance is near zero, you will usually see rounded corners and small blobs where the nozzle slows down.
• At the very top, where pressure advance is high, corners can look slightly pinched or even show a dimple followed by a light section after the turn.
• Somewhere in the middle you should see a band of layers where corners look clean and walls are consistent before and after the turn.

If your tower printed with tall enough layers, you can measure from the base up to that sweet spot with a caliper and calculate the pressure advance value using the starting value and the factor per millimeter.
Many interfaces will also show the current pressure advance in the console as the tower prints, which makes it easy to note the range where quality looks best.

5. Set the pressure_advance value in printer.cfg

When you are happy with the visual result, copy that value into your Klipper configuration.
Find your extruder section inside printer.cfg and add or update the line:

[extruder]
# your other extruder settings here
pressure_advance: 0.05  ; example value, use your tuned number

Save the file and issue a firmware restart from your web interface.
After the restart, Klipper will use that pressure advance for all future moves with that extruder.

We like to keep a small comment by each extruder profile that notes the nozzle size, filament type and date when we last tuned it, especially on multi material printers.

Advanced Tips, Upgrades And One Helpful Hardware Tweak

How pressure advance interacts with input shaping and retraction

If you already tuned input shaping using an accelerometer or a ringing tower, pressure advance usually comes next.
Input shaping focuses on motion vibrations.
Pressure advance focuses on extrusion lag.
You want both working together if you plan to push accelerations for faster print times.

Retraction still matters, but once pressure advance is dialed in you may find that you can reduce retraction distance slightly because the nozzle is not over pressurized when it begins travel moves.
We cover how to safely push these speeds and manage heat buildup in the
Klipper input shaping guide.

Why hardened nozzles help at high speeds

As you increase speed and try more abrasive materials, nozzle wear becomes another hidden variable.
A worn brass nozzle can change effective diameter and flow characteristics over time, which affects how your tuned pressure advance value behaves.
Swapping to a hardened nozzle kit gives you more consistent behavior across many hours of printing.

Nozzle Upgrade

 

Version 1.0.0

 

MK8 Hardened Steel Nozzle Kit

A hardened MK8 nozzle kit holds its shape far longer than brass when you print fast with abrasive or fiber filled materials.
In our testing, swapping to hardened nozzles kept line width and pressure advance behavior stable over dozens of high speed calibration runs.

Pros

• Resists wear from carbon fiber, glow and metallic filaments
• Helps keep pressure advance tuning consistent over time
• Multi pack makes it easy to dedicate nozzles per material

Cons

• Slightly lower thermal conductivity than brass
• May require a small temperature bump compared to brass nozzles

Check price on Amazon

If you are already planning upgrades, this is a good moment to skim through
3D printer upgrades that actually matter and decide whether direct drive, linear rails or a new hotend should be on your roadmap.
Pressure advance will still help on stock hardware, but stiff, low play motion systems get the most out of it.

Material profiles and keeping notes

Pressure advance is sensitive to material properties and even pigment additives.
It is normal for PLA from one brand to like a slightly different value than PLA from another, and PETG or TPU can differ even more.

Rather than chasing perfect numbers for each spool, treat pressure advance like temperature.
Pick a good baseline for each material and nozzle type, then adjust slightly if you notice corner quality drifting on a new spool.
Some owners who run printers for small businesses record these baselines alongside the ideas in
profitable 3D printing business ideas, so they can quickly set up repeatable jobs without recalibrating every time.

Klipper Pressure Advance FAQ

Do I need to retune pressure advance for every filament spool

Not necessarily. In practice most users pick one good value per material and nozzle size and only retune when quality clearly degrades.
If you switch between very flexible TPU and rigid PLA or between abrasive and non abrasive blends, expect to use different values for those profiles.

Can pressure advance replace retraction settings

Pressure advance and retraction work together rather than replacing each other.
Pressure advance keeps flow more consistent when the toolhead changes speed.
Retraction is still needed to control oozing during longer travel moves.
Once pressure advance is tuned you may be able to reduce retraction distance slightly, but you should not set retraction to zero in most setups.

Will pressure advance slow my prints down

If anything, a tuned pressure advance lets you use higher accelerations without sacrificing surface quality.
The g-code path and motion plan stay the same.
Klipper simply alters extrusion to match that motion more closely, which is why it is so valuable on high speed printers.

What are signs that my pressure advance value is too high

When pressure advance is set too high, corners can look pinched or even show a small dimple where material is pulled back too aggressively.
You might also notice slight under extrusion immediately after corners as the extruder recovers.
If you see these symptoms, try lowering the value slightly and reprinting a test piece.

Is pressure advance only useful on Bowden printers

No. Bowden printers often benefit the most because the long tube adds more elasticity, but direct drive systems still show a visible improvement, especially on sharp corners and fast perimeter passes.
On compact CoreXY machines with high accelerations, pressure advance can be the difference between sharp logos and slightly rounded text.

What if I use another firmware that calls it linear advance

The idea is similar. In other firmware families you may see the feature referred to as linear advance, but the goal is the same.
It is still about compensating for the lag between extruder motion and nozzle flow.
The commands and tuning procedure are different outside Klipper, so follow the documentation specific to your firmware.