Short, practical answers to the questions readers ask most about spelling and spell-checkers. For fuller treatment, each answer links to the relevant guide.
Can I trust a spell-checker completely?
No — and understanding why is the key to using one well. A spell-checker reliably catches words that are not in its dictionary, but it cannot catch a correctly spelled word used in the wrong place (their for there, form for from). Treat it as a fast first pass that removes the obvious errors, then finish with your own reading. Our guide to how spell-checkers work explains the limit in detail.
Why does my spell-checker miss obvious mistakes?
Almost always because the “mistake” is a real word. The checker compares each word to a list; if the word is on the list, it passes, regardless of whether it is the word you meant. It also cannot judge meaning or, usually, grammar. The errors it misses are exactly the ones a human reader notices, which is why proofreading techniques matter.
Why is it flagging words that are spelled correctly?
Usually one of two reasons. Either the word is genuinely correct but not in the checker's dictionary — a name, a technical term, or a brand — in which case you can add it to your personal dictionary. Or your checker is set to the wrong language or region, so it fights your spellings (flagging British colour against a US dictionary, for example). Setting the correct language usually clears the false alarms.
How do I check spelling in a program that has no spell-checker?
Many plain text editors, spreadsheets, and chat tools check little or nothing. The simplest fix is to draft or paste your text into a program that does check — a word processor or a browser text box — give it a pass, then move the corrected text back. Our guide to spell-check in your programs maps out which tools check what and where the blind spots are.
Do spelling and grammar checking differ?
Yes. Spell-checking asks whether each word is a real word. Grammar-checking asks whether the words fit together correctly — agreement, punctuation, sentence structure. Modern tools blend the two, and both are useful, but both share the same limit: they judge form, not meaning, so neither replaces a careful human read.
Which English spelling should I use?
Use the variety your reader expects — typically American, British, or Canadian English — and, above all, be consistent within a single document. Set your program's language to match so it stops flagging correct regional spellings. The patterns are covered in our guide to English spelling variations.
Is this website a software product or download?
No. This is an independent, educational resource about spelling, proofreading, and writing well. There is nothing to download, buy, or install — only free guidance you can apply in whatever programs you already use. You can read more about this resource. For further reading on writing generally, the Purdue Online Writing Lab is an excellent companion.