Onoto Magna The Pi Fountain pen

Celebrate precision, logic, and timeless design with the Onoto Magna The Pi Fountain Pen, a remarkable writing instrument inspired by one of the most famous constants in mathematics: π. Limited to just 314 pieces worldwide, this exclusive edition pays tribute to the infinite beauty of numbers, making it the perfect collector’s pen for mathematicians, engineers, and enthusiasts alike.

Inspired by the Infinite Beauty of Pi

Crafted from highly polished black acrylic, the Magna Pi Pen features an extraordinary detail: 314 digits of π engraved across the cap and barrel. This intricate engraving transforms the pen into a true celebration of mathematical elegance—where design meets intellectual curiosity.

Heritage Design & Sterling Silver Craftsmanship

Based on the iconic Onoto Magna of 1937, widely regarded as one of the greatest fountain pens ever made, this modern interpretation combines vintage proportions with contemporary refinement.

The pen is enhanced with luxurious sterling silver details, including:

Three hallmarked cap bands

• The signature Onoto Chevron clip
• A sterling silver cap button engraved with the Onoto cipher
• A matching sterling silver barrel button
• These elements create a perfect balance between classic heritage and modern sophistication.

Exceptional Writing Performance

Engineered for balance, durability, and comfort, the Magna Pi delivers a smooth and reliable writing experience. It features an Onoto size 7 nib in gold-plated stainless steel or an optional 18ct gold upgrade, available in Fine, Medium, or Broad, with custom nib options on request.

The pen uses a convenient cartridge/converter filling system, compatible with standard European cartridges for ease of use.

Key Features

• Limited edition of 314 pieces worldwide
• Engraved with 314 digits of π on cap and barrel
• Inspired by the iconic Onoto Magna 1937 design
• High-density black acrylic construction
• Sterling silver cap bands, clip, and fittings
• Onoto size 7 nib (gold-plated steel or optional 18ct gold)
• Nib sizes: Fine, Medium, Broad (custom grinds available)
• Cartridge/converter filling system
• Length (capped): 144 mm | Weight: 25–32 g

Where Mathematics Meets Craftsmanship

The Onoto Magna The Pi Fountain Pen is more than a writing instrument—it’s a tribute to the elegance of numbers and the art of precision engineering. With its limited availability, historic design, and intricate detailing, it stands as a unique collector’s piece for those who appreciate both science and fine writing.

About Onoto

Onoto is the quintessential British fountain pen maker, renowned for combining historic innovation with the preservation of traditional craftsmanship. In 1905, Onoto revolutionised the writing world with the introduction of Onoto the Pen, the first ever self-filling fountain pen. This breakthrough established the brand as a pioneer in writing technology and laid the foundation for a legacy of ingenuity within the world of fine writing instruments.

Today, Onoto continues this tradition by creating handmade, limited-edition fountain pens that blend heritage, craftsmanship, and innovation. Each collection reflects stories from history and culture, making every pen more than just a writing instrument. Highly valued by collectors and connoisseurs, Onoto pens appeal to those who appreciate the rituals of writing and the cultural narratives that help reveal the timeless beauty of the written word.