Mempool.space also has this
mempool.space/tools/calculator
Apparently they have some way of not tracking what you're checking dyor
bullishCalc v0.0.40 fixes issues with getting #bitcoin exchange rates and adds some ASCII art! 😎
Check it out here: https://bullishcalc.vercel.app
Don’t forget it’s a PWA so it can be added to your home screen. 🤙 
Discussion
I was actually inspired by that one. What’s the concern from the tracking standpoint?