"Further" vs "Farther"

Welcome to the Grammar Minute, where we're saving the English language sixty seconds at a time! I'm Lauren Smyth, and today's episode is a fairly simple review of a grammar rule that gets abused all the time. What's the difference between "further" and "farther"?
People use these words like they're synonyms, but even though both technically refer to distance, they're referring to completely different kinds of distances. "Farther" is spatial, physical distance--the grocery store is farther from my house than the gym. "Further" is metaphorical space, as in "you've thought further ahead than me." The key to remembering the difference is remembering that "far" literally means "far" in space.
If worst comes to worst and you can't remember the difference, at least be consistent. There's nothing weirder for the reader than seeing the same word spelled multiple ways on the same page for no apparent reason.
That's your Grammar Minute! Visit thegrammarminute.com for more tips and tricks.