Calculator
Advanceddecimals
W
H
W
H
A
:
B
Use A:B ratio. Example 1:50 reduces originals. For enlargement use 2:1 etc.
%
Tip: press
Enter to calculateQuick Result
Enter values and press Calculate.
The download contains the Results table below.
Results
| # | Mode | Original (W×H) + Unit | Scale | Scaled (W×H) + Unit | Factor |
|---|
Example Data
| Case | Description | Inputs | Expected |
|---|---|---|---|
| 1 | Map reduction 1:50 | Original 200 mm × 100 mm, ratio 1:50 | Scaled 4 mm × 2 mm |
| 2 | Poster enlargement 2:1 | Original 21 cm × 29.7 cm, ratio 2:1 | Scaled 42 cm × 59.4 cm |
| 3 | Percent scaling 40% | Original 10 in × 8 in, 40% | Scaled 4 in × 3.2 in |
| 4 | Unit conversion in output | Original 3 ft × 2 ft to cm at 100% | Scaled 91.44 cm × 60.96 cm |
Use these to verify calculations or as templates for your own entries.
Formula Used
Let f be the scale factor. A ratio A:B means f = A / B. A percentage P% means f = P / 100. In reduction scenarios f < 1; in enlargement scenarios f > 1.
- Find Scaled Size: Ws = Wo × f, Hs = Ho × f
- Find Original Size: Wo = Ws / f, Ho = Hs / f
- Find Factor: f = Ws / Wo (or height equivalents). With aspect lock we compute from whichever sides are provided.
Units are converted using exact constants: 1 in = 25.4 mm, 1 ft = 12 in, 1 m = 1000 mm, 1 cm = 10 mm. Conversions are applied consistently so that arithmetic is performed in base millimeters and then presented in the requested output unit.