Pressure Advance Calibration Calculator
Enter the best and acceptable sections of a pressure-advance test to convert them into a setting and a narrower follow-up test. The result also gives the matching Klipper, Marlin, or RepRapFirmware command.
Recommended pressure advance0.0645
- Acceptable pressure advance range
- 0.06 to 0.069
- Result uncertainty
- ±0.0045 around 0.0645
- Fine-test increment
- 0.0009
- Fine-test start and end
- 0.06 to 0.069
- Klipper fine-tower factor
- 0.00045
- Command to apply result
- SET_PRESSURE_ADVANCE ADVANCE=0.0645
- Klipper fine-test command
- TUNING_TOWER COMMAND=SET_PRESSURE_ADVANCE PARAMETER=ADVANCE START=0.06 FACTOR=0.00045
This converts the reading you chose; it cannot judge corner quality or confirm that the printed test used suitable speed, acceleration, temperature, and flow.
How to use this calculator
- Choose the firmware and the way your calibration print identifies each candidate value.
- Enter the test start and its value change per millimetre, line index, or printed label.
- Enter the cleanest reading and the lowest and highest readings that still look acceptable.
- Use the acceptable range to print a finer test, then verify the final setting with your normal profile.
How pressure advance is calculated from a test
A calibration print assigns a different pressure-advance value to each height, indexed line, or printed label. This tool converts the section you judged visually with the same linear relationship used by a Klipper tuning tower:
V(x) = S + x × d
S is the starting value, x is the measured height, zero-based line index, or pattern label, and d is the value change per unit. The recommended value is V(best). Klipper's guide gives the same calculation: a tower starting at 0 with a factor of 0.020 and a best height of 12.90 mm gives 0.258.
Do not rely on one apparently perfect point when several adjacent sections are usable. Enter the lowest and highest readings whose corners remain acceptable. Their converted values form the acceptable range. The calculator reports its midpoint and half-width as a practical uncertainty: M = (VL + VH) / 2 and U = (VH - VL) / 2. That band describes your visual selection from this print, not a statistical confidence interval.
Designing a finer test
The acceptable range is also a useful next test. Its width is W = VH - VL. Dividing it by the number of requested intervals gives the finer spacing: dFine = W / n. For a Klipper tower that uses a chosen height H, the matching factor is FACTORfine = W / H and the start is the low acceptable value. The generated command covers the same value span over the new tower, rather than repeating a broad first pass.
For an indexed-line test, line zero is the first line. If the print calls that first line “1”, subtract one before entering it. For a pattern whose labels are already pressure-advance or K values, use a start of zero and an increment of one. Measure tower height from the test's defined zero point, not automatically from the bottom of the complete model.
What moves the result most
The chosen visual band matters more than the calculator arithmetic. Look for the transition from corner bulging at too little advance to rounded corners or poor extrusion before a corner at too much advance. Klipper recommends preferring the lower height when the choice is uncertain. Extruder design, nozzle, filament, temperature, flow, speed, and acceleration can all change the useful setting, so tune extrusion distance or rotation distance and temperature first.
What this calculator leaves out
This tool only translates observations from a printed test. It cannot inspect corners, prove the test g-code changed the setting as expected, or diagnose ringing, flow error, seam behavior, or mechanical limits. It also does not convert between Marlin Linear Advance K and Klipper pressure advance; those firmware parameters use different scales. Check the generated command against the firmware version and printer configuration before applying or saving it.
Worked example
Suppose a Klipper tower starts at 0 with FACTOR=0.005. The cleanest corners are at 12.9 mm, and corners from 12.0 to 13.8 mm are still acceptable. The recommended value is 0 + 12.9 × 0.005 = 0.0645. The acceptable range is 0.0600 to 0.0690, with midpoint 0.0645 and uncertainty ±0.0045.
With ten fine-test intervals, the increment is 0.0090 / 10 = 0.0009. A 20 mm fine tower therefore uses FACTOR=0.0090 / 20 = 0.00045 and starts at 0.0600. The resulting Klipper command is TUNING_TOWER COMMAND=SET_PRESSURE_ADVANCE PARAMETER=ADVANCE START=0.06 FACTOR=0.00045.
Common questions
How do I calculate pressure advance from tower height?
Multiply the height measured from the tower’s defined zero point by its factor, then add the tower start value. For example, a 12.9 mm reading with START=0 and FACTOR=0.005 gives 0.0645. Klipper documents this same start-plus-height-times-factor relationship for its tuning tower.
What FACTOR should I use for direct-drive and Bowden extruders?
Klipper’s starting examples use 0.005 for direct drive and 0.020 for a long Bowden extruder, but they are test ranges rather than universal answers. The useful factor depends on the extrusion system and should span enough values to show the transition from too little to too much advance. A fine test should use the narrower factor calculated from the acceptable band.
Is Marlin Linear Advance K the same as Klipper pressure advance?
No. Both features compensate for pressure changes in the melt zone, but their values use different firmware-specific scales and should not be copied between systems. Use a calibration test made for the firmware running on the printer, and apply the command that matches it.
Which corner of a pressure advance tower should I measure?
Inspect the corners that the test was designed to stress and look across all of them, rather than choosing an isolated good-looking spot. Choose the band where corner bulges have settled without rounding or under-extrusion before the corner. If two nearby settings are equally convincing, Klipper advises choosing the lower one.
When should I rerun pressure advance calibration?
Rerun it after changing the extruder, nozzle, filament type or spool, and when important temperature, flow, or acceleration settings change. A setting is profile-specific enough that it should not be transferred blindly to another printer or material. Recheck it when corner quality changes without another clear cause.