By Simon Pilgrim
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Magnitude has a database of over 500 different units from the scientific, historical, astronomical and natural worlds and goes way beyond converting between the common (boring) metric, US and imperial units to help you understand quantities in real world terms by answering the big questions of today such as:
"How much does that weigh in Blue Whales?"
"How long is that in terms of London double decker buses?"
"How does this compare to an area the size of Texas?".