How to Draw Straight Lines on an Online Whiteboard
Three methods for perfect straight lines: the line shape tool, the Shift+drag shortcut, and the connector/arrow tool. Each serves a different purpose — this guide explains when and how to use each one.
Method 1 — The Line Shape Tool
Best for: standalone straight lines, underlines, dividers, and ruled guides.
Open the Shapes Panel
Click the Shapes tool in the toolbar (the square/rectangle icon). A shape picker will appear. Select Line from the options — it looks like a diagonal slash.
Click and Drag to Draw
Click on the canvas at your starting point, hold the mouse button (or touch on mobile), and drag to where you want the line to end. Release to place it. The line will be perfectly straight regardless of how steadily you drag.
Hold Shift to Lock the Angle
Hold Shift while dragging to constrain the line to exactly 0° (horizontal), 90° (vertical), or 45° (diagonal). Release Shift before releasing the mouse to keep that angle. This is the fastest way to draw a perfectly level or perfectly vertical line.
Adjust Colour and Thickness
Before or after drawing, use the toolbar to set the stroke colour and line width. Thinner lines work for underlining; thicker lines create visible dividers or borders in diagrams.
Method 2 — Shift+Drag with the Pen Tool
Best for: quick freehand lines without switching to the shapes tool.
If you're already drawing with the pen tool and need a quick straight line without switching tools: hold Shift, then click and drag. The pen will draw a straight line constrained to horizontal or vertical. This is the fastest shortcut when you're mid-sketch and need one clean line without breaking your flow.
Method 3 — Arrow and Connector Tool
Best for: flowcharts, diagrams, and lines that connect two shapes.
For diagram work, the connector/arrow tool is better than the line shape. Connectors snap to the edges of shapes — draw from the edge of one rectangle to the edge of another and the line will stay attached even if you move the shapes. They also have optional arrowheads on one or both ends.
Select the Arrow tool from the toolbar, click on your first shape's edge, and drag to the second shape. The connector will route itself as a straight or angled line between the two.
Straight Lines by Use Case
Which method to choose depending on what you're drawing.
| Use Case | Best Method | Tip |
|---|---|---|
| Horizontal divider line | Shapes → Line + Shift | Shift locks to exactly 0° |
| Vertical margin line | Shapes → Line + Shift | Shift locks to exactly 90° |
| Diagram connection between boxes | Arrow / Connector tool | Snaps to shape edges |
| Quick underline while sketching | Pen + Shift drag | No need to switch tools |
| Timeline axis line | Shapes → Line + Shift | Increase stroke width for visibility |
| 45° diagonal accent line | Shapes → Line + Shift | Shift snaps to 45° as well |
Frequently Asked Questions
Why does my freehand pen line come out wobbly?
The pen tool draws exactly where your hand moves — it's designed for natural freehand. For a straight line, always use the Shapes → Line tool or hold Shift. The pen tool cannot produce a geometrically straight line without the Shift shortcut.
How do I draw a dashed or dotted line?
Select the line after drawing it, then look for the stroke style option in the toolbar — you can switch between solid, dashed, and dotted stroke styles.
Can I add an arrowhead to a straight line?
Yes — after drawing a line with the Shapes → Line tool, select it and choose an arrowhead style from the stroke options. Alternatively, use the Arrow tool from the start to get a line with a built-in arrowhead.
How do I draw a line of a specific length?
Draw the line freely, then select it and use the selection handles to resize it. Hold Shift while resizing to keep the line angle locked as you adjust its length.
Do straight lines work on touch / mobile?
Yes — on touch devices, tap the Shapes tool, select Line, then tap and drag across the canvas. The Shift shortcut isn't available on touch, but the line tool always draws straight regardless of finger steadiness.