Free tool
Free online abacus
A virtual Japanese soroban for any phone, tablet or computer. Tap a bead to move it; the number under each rod shows its value.
Your number
How to use the online abacus
- Each rod is one digit. The bead above the bar is worth 5; each bead below it is worth 1.
- A bead only counts when it touches the bar. Tap a bead to push it to the bar or away from it — the beads next to it move too, just as on a real soroban.
- The digit under each rod and the big number above update as you go.
- Type a number and press Show it to see how it looks in beads.
Things to try
- Show your age, then the year you were born.
- Set 4, then add 1. There is no room for another bead, so how do you do it? Hint: little friends.
- Set 3, then add 7 so the ones rod carries into the tens.
- Set 99 and add 1. Watch two carries happen in a row.
Want lessons, not just a board?
The guides explain every move with pictures, the worksheets give you sums to practise on this board, and the Bead Buddies game coaches each move and times you.