Calibrate your extruder: mark filament, extrude 100 mm, measure what actually moved, and get the corrected steps/mm to save with M92.
New e-steps = current × requested ÷ actual. Mark the filament (e.g. 120 mm above the extruder entry), extrude 100 mm at low speed with the hotend at temperature, then measure the remaining distance to the mark to get the actual figure. Save with M92 E… then M500.
Heat the hotend, mark the filament a known distance above the extruder (say 120 mm), tell the printer to extrude 100 mm slowly, then measure the distance left to the mark. If 96 mm actually went in, new e-steps = current × 100 ÷ 96.
Send M503 in a terminal and look for the M92 line; the E value is your current steps/mm. Common defaults are 93 for many Creality bobbins-style extruders and 415 for geared extruders like the BMG.
Send M92 E followed by the new number, then M500 to store it to EEPROM. On Klipper, set rotation_distance instead; the same measurement drives the correction the other way around.