Free · 2D geometry calculators 📏

Rectangle Linear & Area Scale Comparison

Compare original and scaled rectangle dimensions, including the squared relationship between length scale and area scale.

Calculator inputs

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Enter the known values in the units shown. Results update as you type.
Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
Use the worked example to check the method. Reset restores the starting fields.

Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Scaling a 3 m by 4 m rectangle by 2 gives 6 m by 8 m. Its area grows from 12 m² to 48 m², an area scale factor of 4.

New length = k × original length; new width = k × original width; new area = k² × original area

Enter these known values and leave the other values blank.

A single positive scale factor applies to both directions. Independent horizontal and vertical stretching is a different model.
All dimensions, areas and scale factors must be positive. Values of k below 1 shrink the rectangle; values above 1 enlarge it.
Area scales by k squared. Doubling each side quadruples the area rather than doubling it.
The optional soccer-field unit is a fixed 7,140 m² comparison, not the area of every football pitch. The acre uses the exact international-foot definition.

The positive square root of 2, approximately 1.414214. Enter 2 as the area scale factor to calculate that length scale.

Both sides halve, so area is multiplied by 0.25. A 12 m² rectangle becomes 3 m².

The international acre is exactly 43560 square international feet; Bookify replaces the rounded captured area factor.