Scale Factor Calculator
Calculate scale factors between actual and scaled dimensions for maps, architectural models, engineering blueprints, and miniature models. Enter any two measurements to find the exact scale ratio, or apply a known scale to convert between real-world and scaled sizes.
🕐 Recent Calculations
What is a Scale Factor?
A scale factor is the ratio between a scaled representation and the actual object it represents. A 1:100 architectural scale means 1 centimeter on the drawing represents 100 centimeters (1 meter) in reality. A 1:24 model car means the model is 1/24th the size of the real vehicle. Scale factors enable accurate proportional representation of objects that are too large (buildings, maps) or too small (cells, circuits) to work with at actual size.
Scale factors are used in architecture (1:50, 1:100, 1:200 drawings), engineering (full-size, half-scale prototypes), cartography (1:25,000 to 1:1,000,000 maps), model building (1:24, 1:48, 1:72 miniatures), 3D printing (scaling models to fit print beds), and photography (macro magnification ratios like 2:1 or 1:1). Understanding scale factors ensures accurate measurement, planning, and fabrication across all these disciplines.
使用される計算公式・方程式
この計算ツールは5つの主要な公式を使用しています：
1 Scale Factor Calculation ▼
Divide the new measurement by the original measurement. A 3 cm model of a 6 m object has a scale factor of 3/600 = 1/200.
2 Scaled Size from Factor ▼
Multiply the original measurement by the scale factor. A 10 m wall at 1:50 scale = 10 × (1/50) = 0.2 m = 20 cm.
3 Original Size from Scaled ▼
Divide the scaled measurement by the scale factor. A 4 cm line on a 1:100 map = 4 / (1/100) = 400 cm = 4 m.
Explore all calculation options on the 比率計算ツール home page.
比率計算ツールの使い方
この比率計算ツールは、以下の3ステップで簡単にご利用いただけます：
数値を入力
入力欄に既知の比率の値を入力します。求めたい未知数の入力欄は空欄のままにしておきます。
モードを選択
比率モード（解く、簡素化、スケーリング）を選択します。各モードで異なる計算式が適用されます。
結果を確認
計算するボタンを押します。結果画面に答えと、視覚的な比率バー、円グラフ、詳細なステップバイステップの解決プロセスが表示されます。
実例問題と段階的な解説
本比率計算ツールを使って、以下の3つの例題をステップバイステップで解決するプロセスです：
入力 1 Find scale factor: 5 cm model of a 10 m building
入力 2 Scale a 15 m room to 1:50 blueprint
入力 3 Find real distance from a map measurement of 8 cm at 1:25000
よくある質問 (FAQ)
How do I calculate a scale factor? ▼
Scale Factor = Scaled Size ÷ Actual Size. If a 5-meter wall is represented as 50mm on a drawing: Scale = 50mm ÷ 5000mm = 1/100, or 1:100. If a model car is 200mm and the real car is 4800mm: Scale = 200/4800 = 1/24, or 1:24.
What does 1:100 scale mean? ▼
1:100 means 1 unit on the drawing or model represents 100 of the same units in real life. So 1cm on paper = 100cm (1 meter) actual. A 12-meter-long building would be drawn as 120mm on a 1:100 blueprint.
How do I convert between different scales? ▼
Multiply by the ratio of the two scales. To convert a 1:50 drawing to 1:100: multiply all dimensions by 50/100 = 0.5 (halve them). To convert 1:100 to 1:50: multiply by 100/50 = 2 (double them).
What is the most common architectural scale? ▼
In metric countries, 1:50 and 1:100 are most common for building plans. In the US, common scales are ¼" = 1'-0" (1:48) and ⅛" = 1'-0" (1:96) for floor plans, and 1½" = 1'-0" (1:8) for construction details.
How does scale factor affect area and volume? ▼
Area scales by the square of the linear factor: 1:10 linear = 1:100 area. Volume scales by the cube: 1:10 linear = 1:1000 volume. A 1:10 scale model building has 1/100th the floor area and 1/1000th the interior volume of the actual building.
What scale do Google Maps use? ▼
Google Maps uses dynamic scaling — the scale changes as you zoom. Each zoom level approximately halves the scale. At zoom level 15 (street level), the scale is approximately 1:4,500. At zoom level 10 (regional), approximately 1:150,000. The scale bar on the map shows the current scale.
How do I calculate actual distance from a map? ▼
Measure the distance on the map, then multiply by the scale denominator. On a 1:25,000 map, a 4cm measured distance = 4 × 25,000 = 100,000cm = 1km actual ground distance.
What is a representative fraction in cartography? ▼
A representative fraction (RF) is the map scale expressed as a ratio, like 1:25,000. It means 1 unit on the map = 25,000 of the same units on the ground. RF is unit-independent: 1cm = 25,000cm = 250m, or 1 inch = 25,000 inches ≈ 694 yards.
How do I scale a 3D model for 3D printing? ▼
Divide the desired model size by the original model size and multiply by 100 to get the slicer percentage. If the original STL is 300mm tall and your print bed fits 150mm: 150/300 × 100 = 50%. Scale uniformly (all axes at 50%) to maintain proportions.
What scale are common model kits? ▼
Aircraft: 1:72 (most popular), 1:48, 1:32. Cars: 1:24, 1:25, 1:43, 1:18. Military vehicles: 1:35 (standard), 1:72. Ships: 1:350, 1:700. Trains: HO 1:87, N 1:160, O 1:48, G 1:22.5. Dollhouses: 1:12 (most common).