You can calculate your reach ratio by the following calculator. You can use this free calculator for any platform like Instagram, Twitter, Facebook, Google, and others.
There are all kinds of online calculators you can find for free on the Internet, but how many of them will generate results in real-time?

The Unique Reach calculator does just that, and it’s a great tool for anyone who’s ever wondered how many eyeballs are on their social media posts, or how many people might click on a piece of content they’ve shared on the web.
A unique reach calculator (also known as a unique visitors calculator) is a tool that can be used for marketing purposes. It will help you figure out the number of unique visitors your website is getting through social media, email, and search engine optimization.
What is unique reach?
The unique reach of your content is the number of unique visitors to your site. If you have a site that has 100,000 visits per month and 10,000 unique visitors then your unique reach is 10%. Any post that you create should have this number as a goal. That way you can see how many new visitors you are bringing in on a monthly basis.
How to Calculate Reach?
The “reach” of an online advertising campaign is the number of people who saw an ad. It’s a simple calculation to make once you know the audience size. Mathematically, reach is defined as the number of total impressions who viewed an advertisement divided by the total number of frequency of the advertisement.
Simply you can calculate the reach ratio by the following formula.
Reach= Total Impression ÷ Frequency
Frequency indicates the reached in the specific period of time in a user/viewer.
How do you calculate cost of unique reach?
Calculating unique reach is a tricky thing, but if you know the formula, it’s easier to calculate. Unique reach is the number of unique users you reached for a given period of time.
Unique reach can be calculated by total amount spent, divided by reach, multiplied by 1,000
Reach vs unique reach Facebook
The Reach and Unique Reach figures are two different measures of Facebook page performance. The Reach figure is the number of people who see a post in their Facebook News Feed or ticker. Unique Reach is the number of people who see a post, even if they have already seen it before.