liminfoArchitecture Scale Calculator
Free web tool: Architecture Scale Calculator
Real Size (Metric)
5.000 m
Imperial
196.85 in (16.404 ft)
About Architecture Scale Calculator
The Architecture Scale Calculator is a precision tool for architects, engineers, drafters, interior designers, and construction professionals who need to quickly convert between drawing dimensions and real-world measurements. Architectural drawings always use a scale ratio — such as 1:100, meaning 1 mm on paper equals 100 mm in reality — and this calculator handles the conversion in both directions instantly.
The tool supports two conversion modes. In "Drawing to Real" mode, you enter a measurement taken from a scaled drawing and the tool calculates the actual physical dimension. In "Real to Drawing" mode, you enter a real-world dimension in meters and the tool calculates how large it should appear on a drawing at a given scale. Results are displayed in both metric (mm and m) and imperial (inches and feet) units simultaneously.
Six common architectural scale presets are built in: 1:20 for detail drawings, 1:50 for detailed plans, 1:100 for standard floor plans, 1:200 for site plans, 1:500 for master plans, and 1:1000 for large-scale urban planning. You can also type any custom scale ratio. All computations happen instantly in the browser with no server round-trips required.
Key Features
- Bidirectional conversion: Drawing to Real (drawing mm to actual size) and Real to Drawing (real meters to drawing mm)
- Six built-in scale presets covering 1:20 (detail) through 1:1000 (urban planning)
- Custom scale input — enter any scale ratio not covered by the presets
- Dual unit output: metric results in mm and m, imperial results in inches and feet simultaneously
- Accurate decimal formatting — results shown to 3 decimal places for precision work
- Real-time calculation with instant results as scale or dimension values change
- Clean two-column responsive layout for side-by-side metric and imperial results
- 100% browser-based — no server calls, works offline once the page is loaded
Frequently Asked Questions
What is architectural scale and why does it matter?
Architectural scale is the ratio between a measurement on a drawing and the corresponding real-world dimension. For example, a 1:100 scale means every 1 mm on the drawing represents 100 mm (10 cm) in reality. Scale allows large buildings and spaces to be represented accurately on manageable paper or screen sizes.
How do I convert a drawing measurement to the real size?
Use the "Drawing to Real" mode. Enter the scale ratio (e.g., 100 for a 1:100 scale) and the dimension you measured on the drawing in millimeters. The calculator multiplies your measurement by the scale factor to give the actual physical size in both mm/m and inches/feet.
How do I calculate what a real dimension looks like on a drawing?
Use the "Real to Drawing" mode. Enter the scale ratio and the real-world dimension in meters. The calculator divides the real dimension by the scale factor to show you exactly how many millimeters that dimension should be on your drawing. Useful for checking drawing accuracy or planning layouts.
What scale is used for standard floor plans?
In architectural practice, 1:100 is the most common scale for standard floor plans of buildings. 1:50 is used for detailed floor plans, 1:20 or 1:10 for construction details, 1:200 for site plans, 1:500 for master plans, and 1:1000 or 1:2500 for urban scale planning.
Can I use this for imperial scaled drawings?
Yes. Although the input for drawing dimensions is in millimeters, all results include imperial conversions (inches and feet). For drawings originally dimensioned in imperial units, you can convert your inch/foot measurement to millimeters first, or use the real-to-drawing mode with the metric equivalent.
What is the formula used for scale conversion?
For Drawing to Real: Real Size (mm) = Drawing Dimension (mm) × Scale Factor. For example, 50 mm on a 1:100 drawing = 50 × 100 = 5000 mm = 5 m. For Real to Drawing: Drawing Size (mm) = Real Dimension (m) × 1000 ÷ Scale Factor. These are the standard formulas used in architectural and engineering drawing practice.
What is the difference between 1:100 and 1:200 scale?
A 1:100 scale drawing is twice as large as a 1:200 scale drawing of the same subject. At 1:100, every centimeter on paper equals 1 meter in reality. At 1:200, every centimeter equals 2 meters. Larger scale numbers mean a smaller drawing — 1:200 fits more area on a page but shows less detail than 1:100.
Does this calculator work for engineering and civil drawings?
Yes, the calculator works for any scaled technical drawing, including civil engineering plans, mechanical drawings, and landscape designs. Simply enter the appropriate scale ratio for your discipline. Common civil engineering scales include 1:500, 1:1000, 1:2500, and 1:5000.