Orthodontic Space Requirement Calculator

Work out orthodontic space requirement instantly with clear inputs, formula shown and shareable results.

About Orthodontic Space Requirement Calculator

Subtracts the available arch length from the summed tooth widths to give the space deficit that drives orthodontic treatment planning.

Formula

Space analysis

Space deficit = sum of tooth widths - arch length available; a positive value is crowding and a negative value is spacing

Worked example

With the default values below, Orthodontic Space Requirement Calculator returns Space deficit of 6.00. Change any input above and every figure here is recalculated in your browser.

Inputs used

Sum of tooth widthsaccepts 30–140 mm: 78 mm
Arch length availableaccepts 30–140 mm: 72 mm

Results

Space deficit: 6.00 mm
Deficit per quadrant: 3.00 mm
Crowding band: Moderate crowding
Typical management: Expansion, stripping or distalisation are typical options

Step by step

1Values used
2Space analysis
3Space deficit= 6.00 mm
4Deficit per quadrant= 3.00 mm
5Crowding band= Moderate crowding
6Typical management= Expansion, stripping or distalisation are typical options

Assumptions and limits

The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.

Frequently Asked Questions

How much space does stripping create?

Interproximal reduction yields roughly 0.3 to 0.5 mm per contact, so a few millimetres per arch.

When is extraction indicated?

Commonly above about 8 mm of crowding, though profile, incisor position and growth all contribute to the decision.