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Triangle Calculator
Solve any triangle from three sides or two sides and the angle between them: angles, area, perimeter and type.
Scale Calculator
Convert real dimensions to scale model or drawing size (and back) for any scale such as 1:24, 1:48, 1:87 (HO) or architectural 1/4″ = 1′.
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How to use this calculator
Enter your values after choosing the type of calculation in the tabs. The result updates as you type; press Calculate to confirm and jump to the result on mobile. Use Share to send the calculator with your result.
How scale works
scale size = real size ÷ N real size = scale size × N
A scale of 1:N means one unit on the model or drawing equals N of the same unit in real life. At 1:48, a 10 ft wall is 120 in ÷ 48 = 2.5 in long.
Common scales
| Use | Scale | 1 ft real = |
|---|---|---|
| Architectural ¼″ = 1′ | 1:48 | 0.25 in |
| Architectural ⅛″ = 1′ | 1:96 | 0.125 in |
| Dollhouse | 1:12 | 1 in |
| Car models | 1:24 · 1:18 | 0.5 · 0.667 in |
| O gauge trains | 1:48 | 0.25 in |
| HO trains | 1:87 | 0.138 in |
| N gauge trains | 1:160 | 0.075 in |
| Hot Wheels | ≈1:64 | 0.1875 in |
Engineering and map scales
Civil drawings use scales like 1″ = 20′ (1:240) or 1″ = 50′ (1:600): convert both sides to inches to get N. Maps write the ratio directly, e.g. 1:24,000 for USGS topo maps, where 1 in = 2,000 ft.
Frequently asked questions
What is 1/4 inch scale?
1/4″ = 1′, which is 1:48. One real foot is drawn as a quarter inch.
How tall is a 6 ft person in HO scale?
72 in ÷ 87 ≈ 0.83 in (21 mm).
About this tool
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- Formula tests passed · human review pending
- Last updated
- 31 Oct 2026
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