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Open Space Requirement Calculator

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

About Open Space Requirement Calculator

Layout regulations require a minimum share of the site to be set aside as usable open space, commonly ten percent, and it must normally be in consolidated parcels of a minimum dimension rather than scattered leftovers. Comparing provided against required shows the shortfall that has to be found from saleable area.

Formula

Open space requirement

Required = layout area x required percentage; shortfall = provided - required

Worked example

With the default values below, Open Space Requirement Calculator returns Open space required of 2,000.0. Change any input above and every figure here is recalculated in your browser.

Inputs used

Layout areaminimum 0.1 m²
20,000 m²
Open space requiredaccepts 1–40 %
10 %
Open space providedminimum 0 m²
1,800 m²

Results

Open space required
2,000.0 m²
Shortfall or surplus
-200.0 m²
Open space provided
9.00% %
Compliance
Shortfall — additional open space required

Step by step

  1. 1Values used
  2. 2Open space requirement
  3. 3Open space required= 2,000.0 m²
  4. 4Shortfall or surplus= -200.0 m²
  5. 5Open space provided= 9.00 %
  6. 6Compliance= Shortfall — additional open space required

Assumptions and limits

  • The result is derived only from the 3 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.
  • Preliminary estimate only. Open space definitions, minimum dimensions and percentages are set by local development control regulations.

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

Preliminary estimate only. Open space definitions, minimum dimensions and percentages are set by local development control regulations.

Frequently Asked Questions

How is the Open Space Requirement figure worked out?

Required = layout area x required percentage; shortfall = provided - required. Layout regulations require a minimum share of the site to be set aside as usable open space, commonly ten percent, and it must normally be in consolidated parcels of a minimum dimension rather than scattered leftovers.

Do setbacks count as open space?

Generally no. Regulations usually exclude setbacks, road margins and areas below a minimum dimension, because the intent is usable recreational space rather than residual land.

What values do I need to enter?

This calculator takes 3 inputs: Layout area, Open space required, Open space provided. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.

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