# Using an Architect's Scale Ruler
Drawings are shrunk to a **scale** — for example, **¼" = 1'-0"** means every quarter-inch on paper equals one real foot. An **architect's scale** (the triangular ruler) lets you read real sizes off a drawing.
## How to use it
1. Find the drawing's **scale** (in the title block or under the drawing).
2. On the triangular ruler, find the **matching scale** (it has several — ¼, ⅛, ½, etc.).
3. Lay that edge along the line you're measuring, start at **0**, and read the **feet** directly off the marks.
## The golden rule
**Always trust the written dimension over scaling.** Drawings can be printed at the wrong size, and anything marked **NTS (not to scale)** should never be measured. Scale only when there's no written dimension — and then double-check.
**Takeaway:** Match the scale ruler to the drawing's scale to read real sizes — but written dimensions always beat scaling.
> *Educational overview — practice with a real plan set. The more drawings you read, the faster it clicks.*
