I built a free knitting calculator site — what tools would you want added?

Hi everyone! I made https://knitivy.com, a free collection of 20+ knitting calculators. No signup, no paywall.

Some of the tools:

• Gauge & cast-on calculator
• Increase/decrease planner
• Circular yoke calculator
• Hat crown decrease calculator
• Mosaic pattern generator (upload an image → knittable chart with color palette, exportable as PNG/PDF)
• Yarn weight guide, needle size converter, and more

I'm actively adding new features and would love your input — what kind of knitting tools or calculators do you wish existed? Any feedback is welcome!