Finding out where your site ranks

Do you know of any free online tools that can tell me where my website ranks in Google? Or is it just something that you find out by manually looking through Google yourself?
Their are some tools, which provides you the data of your website position in Google search results. But you can't relay on this data, so it's better to check the data manually.

One of the best tool I have tried with almost accurate data is Semrush.
Semrush is displayed your targeted keyword rank in Google. You can use browser extension "SERP trends" which use for manually ranking check it's counting all listing directory on SERP and last updated rank.
Given that google records a history of a browser and changes your serp results on that , it changes on your proximity ( yes even for organic results ) and that google also traces an ip ( this can be your own or a tools proxy ) that is constantly checking your site , it does whats called Google dance, it will throw up your rankings , and see your reaction if you try to spam it with new links or do nothing.

Google HATES automated tools especially rank trackers , they can track time btween queries , if it follows human behaviour ect ect.

Lastly google results also work on trends if you are searching rock celebrities today you might get a article on oprah ( because for some reason a ton of people looked oprah up directly recently ) The next few days that can change. THere is absolutely no certian way of saying i rank one two or 20 . Even the device used affects your ranking. Your best bet is to filter results to your country , or town on gwt and use that average position. Traffic is always also a very good indicator of ranks.