Pressure Advance Tower Calculator

What does this calculator do?

Convert the physically selected best tower height to a coefficient. The calculator cannot inspect corner quality.

How to use the calculator

1. Collect measurements and check units.
2. Tune feed and temperature first; validate at normal acceleration. Store values per nozzle and material.
3. Record assumptions and check the result before applying it.

How the calculation works

Coefficient = start + height × factor. Factor must match the tower's per-height procedure. Klipper and Marlin coefficients are not interchangeable.

Practical calculation example

Understanding the results

Tune feed and temperature first; validate at normal acceleration. Store values per nozzle and material.

The tower must match the formula

This calculator converts a chosen tower height into a pressure-advance coefficient for a test whose value increases linearly with height. Enter the actual starting value, increase per millimetre and measured height above the procedure's defined origin. The tool cannot identify the best layer visually. It also cannot infer how the tower was generated. A stepped tower that changes value once per block needs its own mapping and is not automatically equivalent to a continuous height-based increase. Read the generated test's instructions before entering its labels.

The arithmetic and its direction

Value = start + height × increase. If the test starts at zero and increases by 0.005 per millimetre, a selected height of 20 mm gives 0.100. At 12 mm it gives 0.060. A nonzero start must be retained: starting at 0.020 with 0.005 per mm and 12 mm height yields 0.080. The increase is a value-per-height quantity, not the full change over the entire tower. The decimal result is only as reliable as the chosen region and the correspondence between the physical height and generated value.

Use the right height origin

Many towers include a base or startup region. Whether that height belongs in the formula is determined by the generator's procedure. Measure from its stated origin instead of subtracting an arbitrary base thickness because a tutorial used another model. A 2 mm origin error with a 0.005/mm slope changes the coefficient by 0.010. That is not a rounding issue. Record the generator, starting value, slope and origin with the print so the selected height can be traced back to one specific calibration test.

What pressure advance is intended to change

Extrusion pressure does not respond instantly to changes in motion. A pressure-advance mechanism modifies extrusion around acceleration and deceleration to improve transient deposition. The visually selected region often involves corner behaviour and the balance between bulging and insufficient material. It is distinct from the overall material flow ratio and from the hotend's sustained melting capacity. A pressure-advance adjustment cannot make a blocked nozzle flow correctly or increase the maximum amount of polymer that can melt steadily at a chosen temperature.

Prepare a meaningful test

Use a mechanically sound feed system, an appropriate temperature and consistent material condition. Follow the tower procedure's required speed and acceleration conditions so its visual comparison is meaningful. Do not combine unrelated profile changes while printing the tower. If the test is dominated by ringing, poor cooling, unstable adhesion or obvious under-extrusion, resolve those causes before selecting a coefficient. A clean experimental baseline is more useful than choosing a mathematically precise height from a defective test. Keep the same nozzle and material when validating the result.

Evaluate a region rather than one perfect corner

Inspect several corners and nearby heights after cooling. Look for a repeatable improvement rather than one unusually clean side. A range of adjacent heights may appear similarly good; that indicates limited visual resolution, not evidence for unlimited decimal accuracy. A follow-up test with a narrower sweep can distinguish the region more clearly. Examine both bulging and missing material. Choosing an excessive coefficient merely because it removes a bulge can introduce another defect during transitions. The calculator presents the value at your selected height but cannot balance those physical tradeoffs.

Firmware values need their own conventions

Use the coefficient in the firmware or slicer feature for which the test was generated. Klipper pressure advance and Marlin linear advance are different implementations; a number should not be assumed interchangeable between them. The starting value and slope must correspond to the actual firmware command or generator. Applying a value also depends on configuration and persistence. Verify the printer is using the new setting, and avoid conflicting slicer start commands that silently overwrite it at the next job. Retain the earlier value so the change can be reversed.

Confirm with representative production geometry

Print a normal part using the candidate value and typical operating acceleration, not only the tower. Compare straight segments, corners, short paths and seams with the previous setting. If a different material, nozzle or extrusion system changes behaviour, run a new physical test rather than extrapolating by colour or printer name alone. Store the accepted coefficient with its tested conditions. A good tower result is a calibration proposal; production validation establishes whether it helps the actual work without hiding flow, motion or cooling problems.

Advanced tips

• Tune feed and temperature first; validate at normal acceleration. Store values per nozzle and material.
• Photograph and label several tower faces before changing the profile, so the selected region remains documented after the test model is discarded.

Common mistakes

• Measuring from a different height origin than the generator defines.

Frequently asked questions

Sources & methodology

Mathematical results depend on the supplied inputs. Material properties and machine limits need confirmation for your exact equipment.

• Klipper: Pressure advance ↗