OpenRefine is a powerful free, open source tool for working with messy data: cleaning it; transforming it from one format into another; and extending it with web services and external data.
Drill through large datasets using facets and apply operations on filtered views of your dataset.
Fix inconsistencies by merging similar values thanks to powerful heuristics.
Match your dataset to external databases via reconciliation services.
Rewind to any previous state of your dataset and replay your operation history on a new version of it.
Your data is cleaned on your machine, not in some dubious data laundering cloud.
Contribute to Wikidata, the free knowledge base anyone can edit, and other Wikibase instances.
And much more to discover in our documentation.