free keyword difficulty checker tool?

Seo Powersuite is a great collection of tools.. Its Rank Tracker Tool his a really good keyword tool which can tell you the difficulty and KEI.
The free version has only one drawback that wont be able to save ypur projects.
Overall, its a great tool.

KeywordSEOPro. Just put in your list of keywords and you can choose which ever Google domain you like including google.nl.
This program uniquely combines website authority and page authority - total page reputation.
Regards
David

Use keywordSpy, its very easy to use and they suggest you other keywords according to your targeted keywords.

KeywordSEOPro and SEO Powersuite are good options.

I use seo powersuite and it does what i need.

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Diamond Limousines

People use different words when they search for online content. These search terms are called keywords.Keyword research tools can help you discover topics that people are currently searching for that are related to your expertise. Use this as a springboard to launch another 25 articles that are each 400-750 words and relate to the topics your potential audience is searching for. Provide articles that answer the readers' questions in their search query.Popular Keyword Research Tools:Wordtracker: generates keywords for search engine and website optimization.Keyword Research Tools from Wordtracker Discovery: compiles keyword search stats from worldwide search engines.http://www.keyworddiscovery.com/Goodkeywords: downloadable freeware that queries a number of popular search engines to identify good keywords.http://www.goodkeywords.com/Google Alerts: email updates of the latest relevant Google results based on your choice of topic or keywords.http://www.google.com/alertsGoogle Suggest: as you type in a keyword, Google offers suggestions and shows the number of results.Google "Yoga" when entered into Google Suggest tells me that I should write articles about "Yoga Journals" or "Yoga Journaling".Key Insight: While you may be tempted to write only about the most popular topics, also remember that these topics have the most competition within the search engines--meaning, you are fighting against hundreds or thousands of competitors to get the attention of the market to your article.Perhaps a better strategy is to focus on the middle to lower "tail" of the market by looking at the 50th-200th most popular keywords or phrases from your keyword research and use them as your basis for your next set of articles. There will be less competition for the 'long tail' than the short list of most popular terms and key-phrases.Tip: Look at how your niche keywords may intersect with a holiday or current event. It's a great way to pick up current interest traffic!

SEO PowerSuite is a good tool to do this job. I am not sure if it's 100% accurate, but you could give it a try with the Free version!

what about Keyword spyglass?? nice tool.

As previously mentioned SEO Spyglass: Website Back Link Checker Tool & Link Popularity Checker is one of the best free tools.