Hello, Firstly, let me point out that I do not have much knowledge in physics. However, after reading a certain book, I wanted to find out more about time dilation. I spent a few days reading about it. Here is the problem: 1. The problem statement, all variables and given/known data I would like to be able to calculate the time dilation at any point of the Earth relative to another. From what I have seen the following method is the most used and the simplest: Method 1 - Use the Lorentz factor to calculate time dilation due to velocity. - Use the Schwarzschild radius to calculate the Gravitational time dilation My issue with this formula is that if we simple substitute v with the speed of the object, we wouldn't be taking into account the rotation of the Earth. (A place in the poles is moving faster than a place on the equator). Furthermore, we wouldn't account for the difference in speed based on the altitude (higher points move faster). Can you think of another factor which needs to be taken into account? How do I account for these factors? This website provides a formula using the angular velocity of Earth rotation. This might take into consideration the height. Could someone let me know how to calculate the angular velocity? Methods 2 and 3 Do you think this formula on time dilation due to gravitation and motion together would be my best option? Do you know where can I find example calculations? Or I can use Kerr metric instead of the Schwarzschild solution. However, I couldn't find examples on how to calculate time dilation using this system. Could someone tell me where can I read more about it? I understand that you might not have time / be able to provide me with complete answers, however, would you mind giving me useful links where I can continue my readings? Thank you.