There are quite a few tools out there that can help you check your SEO rankings. Some of them are free, others come with a premium. A simple search over the Internet will reveal more tools, including tools that operate exclusively online, so you won’t have to download anything.
Don’t expect amazing results regarding the SEO rankings if you use a free tool. As for premium tools, what you pay for them will probably make them unjustified. For that kind of money, you’re better off hiring a professional. Such deep analyses are performed anyway before an SEO project is started.