I've whipped up a JS seed XOR calculator that runs in the browser.
Use at your own risk!
https://github.com/SpaceHodler/SeedXOR

https://imgprxy.stacker.news/v1DNsw0QdK8TsgcP_0Z2nMx6I9lcBPITZPnQSzNzFyI/rs:fit:600:500:0/g:no/aHR0cHM6Ly9pbWFnZS5ub3N0ci5idWlsZC81MjkyMzNkZjIwZGNkMDBkN2EwMDcwMzVmMDIwNWNiMzAwOWJlYjlhYzlkM2RjZTM0ZTI3ODQ2NTFjZGFlMGEzLmpwZw