About PiNumpad. Tau

PiNumpad is a free memory trainer for tau (6.28318530717958...), tau, equal to 2π, the ratio of a circle's circumference to its radius. This page is the guided learning mode: tap each digit with the path visible, building the motor memory before removing the visual scaffold in Play mode.

Guided digit-by-digit entry. Learn mode shows the path and the digits simultaneously as you tap. Each correct tap highlights the next step; the path is always visible. This bridges the gap between passive study and active recall, letting you build the motor pattern before removing the visual scaffold.

Tau simplifies many formulas involving circles and radians, a full turn is τ radians, not 2π. It has a dedicated following among mathematicians who argue it is the more natural circle constant. Tap each digit in order. The path remains visible throughout. When you complete a group, the next group loads automatically. Once the path feels natural in Learn mode, move to Play mode to practice without it.

PiNumpad is designed for maths students, engineers, programmers, and advocates of the tau manifesto who prefer their circle constants in terms of radius rather than diameter. It runs entirely in the browser with no account, no installation, and no cost. Progress is saved locally using your browser's storage.

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