There is no automated way of telling how much your website is worth, it all depends on what a person is willing to pay for it.
Put your site on sale and see the offers you get. The maximum offer you get can be the value of your site.
The tool that you found online calculates the value of my site as 35,000 USD and I will be happy to sell my site if I get this amount.
If this helps: UV a month: ~7500 Page hits: 22 000 It's fully automated website... Revenue: ~50€ a month
I never trust those automated estimates. Take 10 websites in that niche and all 10 of them will show a different worth of your site. And usually, they are several months behind on what's going on with this or that website and so their estimates are quite a bit off.
Based on what the Flippa experts say, you should be able to flip your site for 10 to 12 times your monthly revenue
Don't use websites that calculate website worth because it is far from accurate. Your website is worth what someone is willing to pay for it.
Right now I have serious doubts about any so called 'valuation' of a website. I have a PR3 site and ran across one of those 'valuation' tools, so I thought, why not, it said the site was worth $20,000. WOW I thought, but I knew Flippa has an evaluation tool too, so I used it, $1200 they said and then just for fun I listed it for sale, with a healthy reserve, top bid was $50, so I still have it, off course. So what is it actually worth, with income of nearly $200 a month you can guess what I said to $50