Line counter that separates the blank ones

Yes. A line here is the text between two line breaks, plus whatever follows the final one, so three names typed on three lines count as three whether or not you pressed Enter after the last. The arithmetic is simply the number of line breaks plus one. This is where a text editor can disagree with you: a file that ends with a line break has one empty line at the bottom, which some editors show as a real line and some hide.

Almost certainly word wrap — your editor is counting the rows it drew on screen, not the lines in the text. A single 300-character paragraph with no line break in it fills four rows in a narrow window and two in a wide one, and the count changes when you resize the window. This page counts only real line breaks, the ones you made by pressing Enter, so the figure stays the same however the text is displayed. If your editor has a “soft wrap” or “word wrap” setting, turning it off makes the two numbers agree.

They are counted in the total and again on their own, because both numbers get asked for. A list of 40 entries double-spaced is 79 lines and 40 lines at the same time, and which one you want depends on whether you are checking a format or counting the entries. The blank figure is split further into truly empty lines and lines that hold only spaces or tabs — a distinction that looks pedantic until a mail merge treats a space-only line as real data.

They are the invisible characters at the end of each line, and Windows writes two of them where Mac and Linux write one. Nothing about your text changes, but programs that expect the other style react badly: a file can open with every line run into a single paragraph, or with a stray character showing at the end of each line, or with the whole thing double-spaced. Mixed endings inside one file — usually the result of two people editing it on different machines — are the version most likely to break an import.

Because a text box on a web page rewrites them the instant it accepts text. Every browser normalises what is typed or pasted into a box to the single-character form before your text is ever readable, which means the box can never tell you what the original file used. The clipboard still holds the untouched version at the moment of the paste, so that is where the reading is taken. Type instead of pasting and the panel will honestly report nothing rather than guess.

It depends entirely on where the text is going, which is why the width is yours to set. Subtitles are usually capped at 42 characters a line so they can be read in the two seconds they are on screen; plain-text email has been wrapped at 72 for decades so that quoting does not push it past 80; terminals and many code reviews use 80; and typographers put the comfortable reading measure at 45 to 75 characters, which is why a book page is narrower than your monitor. Set the number your format requires and the list underneath names every line that breaks it.

That figure is already there — “lines with text” ignores every blank and space-only line. It is the number you want when you are counting stanzas of a poem, entries in a list or rows destined for a spreadsheet, because the gaps you added for legibility should not inflate the count. If you would rather remove the gaps than count around them, the remove empty lines tool deletes both kinds, including the ones that only look blank.