K
Kani
Cosmic Abacus
New · Free tool

A free virtual soroban abacus in your browser.

Drag the beads, add numbers up to 15 digits long, and use the same wooden-frame soroban our students use — no signup, no install, free forever.

abacus.kani-math.com

Built for actual practice, not a screenshot demo.

🫳

Drag-to-set beads

Beads track your finger 1:1, snap to the right value on release, and ride in stacks the way a real soroban does. Touch and mouse both work.

📏

3 to 15 rods

Start narrow for first lessons or go wide for multi-digit drills. The thousands rod is tinted so kids spot the separator at a glance.

👁️

Show or hide digits

Toggle the digit row below each rod on and off — perfect for self-check during practice, or to hide and read the value mentally first.

📱

Works everywhere

Web, mobile, tablet. Phone-landscape switches to a side-rail layout so the abacus keeps every bead in view. No account, no install, no tracking.

What is a soroban?

The bead frame above is a Japanese soroban — one heaven bead per rod above the divider, four earth beads below. That 1+4 layout is what separates the modern soroban from the older Chinese suanpan (2+5). Fewer beads, faster math.

Japan has taught the soroban in elementary school for over a century, and still does — because the same clean layout that speeds up addition is also what lets a trained student picture the abacus in their head. That mental image is the foundation of mental arithmetic, and the reason a soroban graduate can outrun a calculator on multi-digit sums.

Ready to slide some beads?

The tool lives at a clean address — paste it into a class chat, a worksheet, or a parent group.

Launch the virtual abacus →

Built and maintained by the Kani Math team. No ads. No upsells. The full program lives at app.kani-math.com when you're ready.