Floor Plan Scale Converter – Architectural Scale Calculator Online

  • Adam
  • November 22, 2025

Free floor plan scale converter to convert between scales like 1:50, 1:100, 1/4″=1′. Calculate actual dimensions from scaled drawings and vice versa instantly.

Floor Plan Scale Converter

Convert Architectural Scales & Calculate Actual Dimensions

Scale Converter

Understanding Floor Plan Scales

Floor plan scales are ratios that represent the relationship between measurements on a drawing and actual real-world dimensions. Architects and designers use standardized scales to create accurate, proportional representations of buildings and spaces.

Scale Conversion Formulas

Scaled to Actual:

Actual = Scaled × Factor

Actual to Scaled:

Scaled = Actual / Factor

How Scale Ratios Work

A scale ratio like 1:100 means that 1 unit on the drawing represents 100 of those same units in reality:

  • 1:50 - 1 cm on plan = 50 cm (0.5 m) actual size
  • 1:100 - 1 cm on plan = 100 cm (1 m) actual size
  • 1:200 - 1 cm on plan = 200 cm (2 m) actual size
  • 1/4" = 1' - 0.25 inches on plan = 12 inches (1 foot) actual

Common Architectural Scales

Metric Scale Usage

Scale Factor Common Use Example
1:20 20 Detail drawings 1 cm = 20 cm
1:50 50 Floor plans, rooms 1 cm = 50 cm
1:100 100 Building plans 1 cm = 1 m
1:200 200 Building layouts 1 cm = 2 m
1:500 500 Site plans 1 cm = 5 m

Imperial Scale Usage (US)

Scale Ratio Common Use Example
3/4" = 1' 1:16 Large scale details 0.75" = 12"
1/2" = 1' 1:24 Detail plans 0.5" = 12"
1/4" = 1' 1:48 Residential plans 0.25" = 12"
1/8" = 1' 1:96 Large buildings 0.125" = 12"
1/16" = 1' 1:192 Site plans 0.0625" = 12"

Frequently Asked Questions

What does 1:50 scale mean on a floor plan?

1:50 scale means that 1 unit on the drawing represents 50 units in real life. For example, 1 cm on the floor plan equals 50 cm (0.5 m) actual size, or 1 inch on the plan equals 50 inches (4.17 feet) in reality. Formula: Actual Size = Drawing Size × 50. This scale is commonly used for detailed floor plans and room layouts.

How do you calculate scale on a floor plan?

To calculate scale: Actual Size = Scaled Size × Scale Factor. For 1:100 scale, multiply drawing measurements by 100. For 1/4 inch = 1 foot scale, the ratio is 1:48, so multiply by 48. The scale factor is the second number in the ratio. Example: 5 cm on a 1:100 plan = 5 × 100 = 500 cm (5 meters) in actual size.

What is the most common floor plan scale?

The most common floor plan scales are 1:50 and 1:100 in metric countries, and 1/4 inch = 1 foot (1:48 ratio) in the United States. Residential plans typically use 1:50 or 1/4" = 1' for good detail visibility, while larger commercial buildings use 1:100 or 1:200 to fit entire floors on standard paper sizes.

How to convert 1:100 scale to actual size?

To convert 1:100 scale to actual size, multiply the measurement on the drawing by 100. Formula: Actual Size = Drawing Measurement × 100. Example: 5 cm on the plan = 5 × 100 = 500 cm (5 meters) in reality. For 2 inches on plan = 2 × 100 = 200 inches (16.67 feet). This scale is standard for architectural floor plans and elevations.

What does 1/4 inch = 1 foot scale mean?

1/4 inch = 1 foot means every 1/4 inch (0.25") on the drawing represents 1 foot (12 inches) in actual size. This equals a 1:48 ratio (12 ÷ 0.25 = 48). To convert: Actual Feet = Drawing Inches × 4. Example: 3 inches on plan = 3 × 4 = 12 feet actual size. This is the most common residential architectural scale in the United States.

Disclaimer: This floor plan scale converter uses standard architectural scale ratios and conversion factors. Results are mathematically accurate based on the selected scale and input values. For professional architectural work, engineering projects, or construction, always verify measurements with proper tools and consult qualified professionals. Scale accuracy depends on proper drawing creation and measurement techniques. This calculator is for estimation and educational purposes.

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