About this video
Calibration part 2: flow rate
If your flow rate is wrong, prints always look a bit off: gaps and rough top surfaces when it's too low, blobs, ridges and tight fits when it's too high. The flow rate (flow ratio) calibration fixes that for each filament.
How to run it
- Open your slicer (Bambu Studio is shown) and go to Calibration → Flow rate.
- Pick the coarse calibration. The slicer generates a plate of test blocks, each with a different modifier.
- Print it and find the block with the smoothest, best-looking top surface.
- Open your filament settings and calculate the new flow ratio:
New flow ratio = current flow ratio × (100 + modifier) ÷ 100
The current flow ratio is the value already in your filament settings. The modifier is the number on your best block.
Example: current flow ratio 0.98, best block modifier +5 → 0.98 × 105 ÷ 100 = 1.029.
- Enter the result in Flow ratio and save the profile.
Tips
- Run it after the temperature calibration (part 1).
- Judge the top surface under raking light. Run your fingertip over it to feel for ridges or gaps.
- The fine pass narrows it down further once the coarse pass is done.
- Prefer doing the maths automatically? Use the flow rate calculator.
FAQ
Do I need this for every filament?
Run it once per filament brand and type, and save the result in that filament's profile.
Flow rate or extrusion multiplier: what's the difference?
They're the same idea. Bambu Studio and OrcaSlicer call it flow ratio, PrusaSlicer calls it extrusion multiplier, and Cura calls it flow.
