Here's a completely blank puzzle provided so that you can use the helper to solve any puzzle. For example, you can fill in the squares from today's newspaper puzzle, or one from a book, or wherever.
This puzzle tries to fill the screen space you give it, so you can resize your browser window to make it bigger or smaller as you want. To fill in a number that you definitely know, use your mouse to left-click on the square and select the number. If you're not sure but want to mark a possibility (for example, the 2 can either be here or here), then right-click on the square instead and select the number. This possibility will be written smaller and grey in the corner of the square, like a pencil mark to remind you.
For more information on Sudokus, and how to solve them, see the main Sudoku page.