Nib-Angle Guide
Work out the stroke width a broad-edge nib produces in any direction for a given pen angle, and find the angle that gives the thinnest and thickest strokes.
Resulting stroke widths
Thinnest stroke at 30°(parallel to the pen angle) · thickest at 120° (perpendicular to the pen angle, the full nib width).
Predicting thick-thin contrast before you write
Broad-edge calligraphy gets its characteristic thick-and-thin letterforms from a simple piece of geometry: the ink line a flat nib lays down is the projection of its edge onto the direction of travel. Hold the pen at a fixed angle and every stroke direction produces a predictable width — strokes parallel to the pen angle come out as hairlines, and strokes 90° away come out at the nib's full width.
This is exactly why changing your pen angle changes the whole character of a hand: a steeper angle shifts where the thick and thin strokes fall relative to vertical, which is the difference between, say, a Foundational hand and an Italic hand written with the same nib. Working out the numbers ahead of time can help you predict how a new pen angle will affect your existing letterforms before you commit ink to paper.
Frequently Asked Questions
What does "pen angle" mean in calligraphy?
Pen angle is the angle between the flat edge of a broad-edge (chisel-tip) nib and the horizontal writing line, held constant as you write. A Foundational hand is traditionally written at about 30°, Italic at 40-45°, and Uncial closer to 0-5° (almost flat). Changing the pen angle changes which strokes come out thick and which come out thin across the whole alphabet.
Why does the same nib produce different stroke widths in different directions?
A broad nib's edge is a flat rectangle, not a point. As you drag it across the paper, the width of ink it lays down is the width of that edge as seen from the direction of travel — its projection onto a line perpendicular to the stroke. Dragging the nib exactly along its own edge direction lays down almost no width (a hairline); dragging it 90° from that direction lays down the full edge width. Every other direction falls somewhere in between, following a sine relationship.
How do I use the thinnest/thickest angle results?
The thinnest-stroke angle equals your pen angle itself — strokes drawn in that exact direction come out as hairlines. The thickest-stroke angle is 90° away from the pen angle and produces the full nib width. Most broad-edge alphabets are designed so the main vertical or diagonal strokes land closer to the thick end and the connecting hairlines land closer to the thin end, which is what creates the classic thick-thin calligraphic contrast.
Does paper or ink change the actual result?
Yes — this calculator gives the geometric ideal based on the nib edge alone. Ink flow, paper texture, nib flex, and hand pressure all affect how a stroke actually looks on the page, so treat the numbers as a planning reference before you put pen to paper, not a guarantee of the exact rendered width.
Educational tool only. Widths are the geometric ideal for a rigid broad-edge nib; real ink, paper, and hand pressure will vary the result somewhat.