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Calcimator

Cephalometric Analysis Calculator

Compute key angular and linear cephalometric measurements (SNA, SNB, ANB, FMA) and compare to normative values.

Inputs

deg
deg
deg
deg
deg
mm
mm
mm

Results

ANB Angle (degrees)

2

Skeletal Classification1
SNA Deviation (degrees)0
SNB Deviation (degrees)0
ANB Deviation (degrees)0
FMA Deviation (degrees)0
Significant Deviations (>2 SD)0
Skeletal ClassClass I (Normal)
Growth PatternNormal (Mesofacial)
U1ProtrusionNo
L1ProtrusionNo
How to Use This Calculator
  1. Enter key cephalometric landmark coordinates from a traced lateral cephalogram.
  2. Input ANB angle, SNA, SNB, and other skeletal measurements as prompted.
  3. Read derived cephalometric values and compare against normative standards.
  4. Review skeletal and dental discrepancy analysis to guide treatment planning decisions.
  5. Use results in the diagnostic workup alongside models and photographs.

How the result changes with SNA Angle (degrees)

SNA Angle (degrees)ANB Angle (degrees)
73-7
79-1
866
9313

What each input means

SNA Angle (degrees)
Sella-Nasion-A point angle. Norm = 82 +/- 2 degrees.
SNB Angle (degrees)
Sella-Nasion-B point angle. Norm = 80 +/- 2 degrees.
FMA / FH-MP Angle (degrees)
Frankfort Horizontal to Mandibular Plane angle. Norm = 25 +/- 5 degrees.
U1 to NA (degrees)
Upper incisor long axis to NA line angle. Norm = 22 +/- 5 degrees.
L1 to NB (degrees)
Lower incisor long axis to NB line angle. Norm = 25 +/- 5 degrees.
U1 to NA (mm)
Upper incisor tip to NA line distance. Norm = 4 +/- 2 mm.
L1 to NB (mm)
Lower incisor tip to NB line distance. Norm = 4 +/- 2 mm.
Wits Appraisal (mm)
AO-BO distance on the functional occlusal plane. Norm = 0mm (F) / -1mm (M).
Sex
0 = Female, 1 = Male. Affects Wits appraisal norm.

What each result means

ANB Angle (degrees)
SNA minus SNB. Indicates skeletal jaw relationship. Norm = 2 +/- 2 degrees.
Skeletal Classification
1 = Class I, 2 = Class II, 3 = Class III.
SNA Deviation (degrees)
Deviation of SNA from normal (82 degrees).
SNB Deviation (degrees)
Deviation of SNB from normal (80 degrees).
ANB Deviation (degrees)
Deviation of ANB from normal (2 degrees).
FMA Deviation (degrees)
Deviation of FMA from normal (25 degrees).
Significant Deviations (>2 SD)
Number of measurements exceeding 2 standard deviations from norm.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    SNA Angle (degrees) = 82, SNB Angle (degrees) = 80, FMA / FH-MP Angle (degrees) = 25, U1 to NA (degrees) = 22 = 9 input(s) provided
  2. Calculate ANB Angle
    ANB Angle
    2 = 2
  3. Calculate Skeletal Classification
    1 = 1
  4. Calculate SNA Deviation
    SNA Deviation
    0 = 0

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