Charts are an awesome way to visualize data. They pack a lot of information into an easy to digest format. Up to relatively recently, if you wanted to create an interactive chart for your website like the ones you see on the New York Times or Bloomberg, you either had to hire a developer or go through the daunting task of learning how to program it. Neither of which could be done in an afternoon.
Fortunately, there are some great online tools you can use that yield great looking and dynamic results with no coding required!
RAW is a great looking tool from Italian research lab Density Design. It not only looks super modern, their tool a joy to use, with clear instructions and a great user experience. While it does not let you upload spreadsheets directly, it is just as easy to copy and paste in your data which it automatically parses into categories you can click and drag your way into creating a cool looking interactive chart. Once the chart is generated, you can embed the code directly into your website, integrating seamlessly into your website design.
Infogram differentiates themselves from the pack by doing several things really well. For starters, you can create awesome looking maps and infographics, not just charts. In fact, the sheer variety of what you can create is astonishing. The premium plan also gives you advanced importing functions, not just important spreadsheets from Excel or Google Sheets, but also connecting JSON from a live API. The free account, while limited, gives you access to many of their features.
For power users: Plot.ly
If you are looking for a tool that scales up into something much more powerful, Plotly is a great way to do it. While the toolset for the free version is rather limited, the professional and enterprise versions allow a much deeper integration with your web app/website. There is even an open source library that is based on D3 should you ever need to export and migrate it.