About this calculator
The Bolton Analysis Calculator estimates anterior and overall tooth-size ratios from mesiodistal tooth-width sums. It helps orthodontic students and clinicians quickly check inter-arch tooth-size proportionality.
Bolton analysis is only one part of orthodontic diagnosis. Tooth shape, crowding, spacing, arch form, occlusion, restorations, and treatment objectives must also be considered.
Uses Bolton anterior ratio of 77.2% and overall ratio of 91.3% as classic reference values. Results are screening aids for orthodontic records, not treatment plans.
Source-mapped orthodontic index
Educational estimate only; not a diagnosis, prescription, or treatment plan.
Formula and method
Anterior Bolton ratio = mandibular anterior sum ÷ maxillary anterior sum × 100. Overall Bolton ratio = mandibular first-molar-to-first-molar sum ÷ maxillary first-molar-to-first-molar sum × 100. Classic reference values are 77.2% anterior and 91.3% overall.
Limitations and when not to rely on this result
- Educational estimate only; not a diagnosis, prescription, or treatment plan.
- Result depends on accurate inputs and may not apply to complex medical situations.
- Use clinician judgment, local guidance, and urgent care pathways when symptoms are severe.
Frequently asked questions
What is the Bolton anterior ratio? +
It is the combined mesiodistal width of the six mandibular anterior teeth divided by the combined width of the six maxillary anterior teeth, multiplied by 100.
What is the Bolton overall ratio? +
It is the mandibular first-molar-to-first-molar tooth-width sum divided by the corresponding maxillary sum, multiplied by 100.
Does a high Bolton ratio mean mandibular excess? +
Usually it suggests relatively larger mandibular tooth material or relatively smaller maxillary tooth material for that segment, but clinical interpretation depends on the full orthodontic record.
Can this plan enamel reduction or buildups? +
No. It can estimate discrepancy, but treatment decisions require orthodontic diagnosis, occlusion analysis, patient goals, and clinician judgment.
Should third molars be included? +
No. Classic Bolton overall analysis uses first molar to first molar, not third molars.