Scale calculator (map, blueprint & model)
Convert distances between drawing and reality using the scale (1:N) — for maps, blueprints and models.
Enter the distance measured on the drawing in centimeters. At 1:1000, 1 cm on the map = 1000 cm = 10 m in reality.
How the calculation works
A 1:N scale means 1 unit on the drawing equals N units in reality. It's what lets a house fit on a blueprint or a map on paper.
- Drawing to real: multiply the measure by N.
- Real to drawing: divide by N.
Mind the units: at 1:100, 1 cm on paper = 100 cm = 1 real meter.
Step-by-step example (1:50)
A wall measuring 8 cm on the plan:
- Real: 8 × 50 = 400 cm = 4 meters
Larger vs smaller scale
The bigger the N, the more reduced the drawing. Architecture models use 1:50 or 1:100; city maps, 1:10,000 or more.
Examples
- 1:100 scale, 5 cm on the plan = 5 real meters.
- A 20 m lot on a 1:200 plan: 2,000 ÷ 200 = 10 cm on paper.
Frequently asked questions
What does 1:50 scale mean?
That each 1 cm on the drawing represents 50 real cm. Common in blueprints and models.
Which is a "larger" scale, 1:50 or 1:100?
1:50 is the larger scale — the drawing is bigger and more detailed. The smaller the second number, the larger the drawing.
How to convert between different scales?
Go back to real size first (multiply by the current scale), then divide by the new scale.
What does a 1:50 scale mean?
Each unit on the drawing equals 50 in reality: 1 cm on paper is 50 cm real.
Does the scale apply the same way to area?
No. At 1:50, length divides by 50 but area by 2,500 and volume by 125,000.
Why do maps include a scale bar?
Because it stays accurate even if the document is enlarged or reduced, unlike the numeric ratio.
Can I measure the drawing instead of reading the dimension?
Only as an estimate. Written dimensions always prevail over measuring the print.
Related calculators
More Math calculators
See all →Scientific calculator
Free online scientific calculator: sine, cosine, tangent, root, power, log, ln, π and parentheses.
Percentage
Calculate percentages every way: X% of Y, increase, discount and percentage change.
Compound rule of three
Solve problems where two quantities vary at once (machines, days, output...), directly or inversely.
Area of shapes
Calculate the area of a square, rectangle, triangle, circle and trapezoid in seconds.
Pythagorean theorem
Find the hypotenuse or a leg of a right triangle (a² + b² = c²).
Logarithm
Calculate the logarithm of a number in any base, plus natural log (ln), log10 and log2.
Trigonometry (sin, cos, tan)
Calculate the sine, cosine and tangent of an angle in degrees or radians.
Slope / grade
Calculate slope as a percentage, the angle and the ratio from rise and run.
Updated on June 30, 2026 · by Rafael Rossi · Methodology & sources