Determining correct frame size for bike

Hi all,
What are the measurements to determine the correct size frame? Is there an online calculator?

Thanks!

KK

What are your fit numbers?

Road bike or Tri bike?

For tri bikes, if you have stack and reach numbers from your fit many frames have a chart (examples below). It’s not unusual for multiple sizes to be “workable,” but go with one where you are closer to the middle of the frame’s range (both for better handling, and future adjustability if your fit evolves).

http://4.bp.blogspot.com/-yYly8MGqLTc/UQDTmuHFHDI/AAAAAAAACyI/dlyHeo4CQsM/s1600/SHIVStack-Reach.jpg

http://tri247.kinsta.cloud/wp-content/uploads/2016/10/cervelo-p5x-kona-everything-you-need-to-know-20.jpg