About CheckFigures
CheckFigures is a set of free tools for schoolwork, one tool per page: calculators for grades and GPA, and chart makers that turn a column of numbers into a picture you can hand in.
Everything happens in your browser
There is no account and no queue. The page you open carries the whole tool: your numbers are read, counted and drawn on your own device, and a chart you download is written by your browser rather than fetched from a server. That is also why the tools keep working on a slow connection once the page has loaded. One button breaks the rule, and only when you press it: “Share a link” sends what is in the tool to our server so that the link has something to open, and the page it makes is public.
What is free
All of it. Every calculator, every chart, as often as you like, with no watermark on what you download and no advertising on the page.
The tools
Built on
- The statistics behind the charts — quartiles, bins, the line of best fit: d3-array and d3-scale (ISC), the same code most charting libraries are built on.
- Pie slices and line paths: d3-shape (ISC). The charts themselves are drawn as plain SVG, which is why the file you download is the picture you saw.
- Reading what you paste from a spreadsheet: Papa Parse (MIT).
- The chart palette is checked for colorblind readers and for black-and-white printing.
Questions, or a number that looks wrong: see the privacy page for how to reach the operator. A grading scale that your school uses and this site does not is worth writing about — it is the kind of thing these pages should handle.