No, i stand by my original statement. I said it would be “off by” as in the “error will be” so the difference is the important bit to calculate that. There are a lot of ways to correctly do the math though

Thank you for your service. It’s super important for every internet comment to contain every pedantic detail every time

Yes,you can use the tire size information to calculate the circumference of the stock and the new tires. The speedometer will be off by the same ratio as the difference in circumferences. If the new tires are already installed and you don’t like geometry, use your gps to check the accuracy of the speedo at a few speeds