Scale Calculator

The length before scaling. Any unit, as long as both lengths use the same one.
For a plan marked 1:100 this is 1. For a 2:1 detail drawing it is 2.
For a plan marked 1:100 this is 100.
Scale factor
2
Scale Factor Calculator
Scale as a ratio
2 : 1
Enlargement or reduction
enlargement
Area scales by
4
Volume scales by
8
Real length from the drawing
500
Drawing scale
1 : 100
Scale factor the other way
0.5
Worked out from OpenStax, Elementary Algebra 2e, section 9.6 and chapter 3: ratios, proportions and geometry applications and 1 other source.
Both lengths must be measured in the same unit; the scale factor itself has no unit.

How this is worked out

4 steps
  1. Scale factor k = new ÷ original = 4 ÷ 2 = 2.
  2. Lengths scale by k, so this is a enlargement.
  3. Areas scale by k² = 4 and volumes by k³ = 8.
  4. Drawing scale 1 : 100: real = drawing × 100 ÷ 1 = 5 × 100 ÷ 1 = 500.

Results are general information, not financial, tax, legal, medical or engineering advice.