Navy and Prussian Blue are near-identical blue shades — they sit within a few degrees of hue, lightness, and saturation of each other. The difference is mostly in name and historical use. Navy (#001F3F) is a very dark blue associated with military uniforms, while Prussian Blue (#003153) is a slightly lighter dark blue with a greener undertone, named after the pigment invented in 1704. Prussian leans teal; navy leans violet.
Four real design scenarios, with the recommended pick based on hue, saturation, and WCAG contrast.
Navy is more saturated (100% HSL vs 100%) so it reads as bolder and more memorable at logo scale, while Prussian Blue can feel washed out when printed small.
Navy hits a 16.56:1 WCAG contrast against white — safer for text-heavy interfaces — where Prussian Blue only reaches 13.43:1 and risks failing AA at small body sizes.
Prussian Blue is a cool-leaning tone that flatters spring/summer collections and warmer skin undertones, while Navy leans cooler and is better suited to autumn/winter layering.
Navy is the more muted of the two (100% saturation) and sits more calmly on large wall surfaces, while Prussian Blue's higher chroma can overwhelm a room when used beyond accent pieces.
Navy (RGB 0,31,63) is a very dark blue at L=12% with a slight violet undertone — the classic color of the British Royal Navy uniform from 1748.
Prussian Blue (RGB 0,49,83) is a slightly lighter dark blue at L=16% with a green-teal undertone — one of the first modern synthetic pigments, discovered in Berlin in 1704.
Text legibility depends on the contrast ratio between foreground and background. WCAG 2.1 AA requires at least 4.5:1 for normal text and 3:1 for large text; AAA requires 7:1. Use these numbers to choose accessible combinations for your design.
Each color has a dedicated page with shades, tints, CSS name, pairings, and color psychology.