Is it 'back and forth' or 'back and fourth'?

It is back and forth. The phrase describes movement in one direction and then the other, and forth means forward. Fourth is a number, so 'back and fourth' makes no sense and is a very common typo.

Is it 'so on and so forth' or 'so on and so fourth'?

The correct phrase is 'and so forth' or 'and so on and so forth.' Here forth means 'onward,' signaling that a list continues in the same way. 'So fourth' is always a misspelling.

Do fourth and forth sound the same?

Yes. In standard American, British and Australian pronunciation, fourth and forth are homophones, both pronounced like FORTH. That is exactly why they are so easy to mix up in writing.

Is it 'Fourth of July' or 'Forth of July'?

It is the Fourth of July, because the holiday falls on the fourth day of July. The number four is hiding inside fourth, which is a good way to check the spelling.

What does 'hold forth' mean?

To hold forth means to talk at length about a subject, often in a way that suggests the speaker enjoys the sound of their own voice. For example, 'Uncle Ray held forth on politics all through dinner.' It uses forth, never fourth.

Should I write 'fourthly' or 'fourth' in a list?

Both are acceptable when numbering points. 'Firstly, secondly, thirdly, fourthly' is common in British and Australian writing, while many American writers prefer 'first, second, third, fourth.' Either way, it is spelled with a u because it comes from four.

Fourth vs Forth: Meaning, Examples and Phrases

Fourth is a number: it means "number four in a sequence" (the fourth floor) or "one of four equal parts" (a fourth of the budget). Forth is an adverb meaning "forward," "onward" or "out into view," as in back and forth, and so forth and set forth.

The two words sound identical, so spell-checkers will not save you, and the mistake shows up everywhere from school reports to company websites. The fix is simple once you notice that fourth contains the word four.

Quick answer: If you are counting, write fourth (four + th): fourth place, the fourth of July, one-fourth. If you mean forward, onward or out, write forth: back and forth, and so forth, bring forth, set forth. Spot the four in fourth and you'll never mix them up.

On this page

What each word means
Where the words come from
Fourth vs forth at a glance
Phrases with "forth" (and what they mean)
Phrases with "fourth"
Grammar notes on "fourth"
"Forth" vs "forward" vs "further"
24 example sentences
US vs UK vs Australia
Common mistakes
Memory tricks
Practice quiz
More homophones that fool spell-checkers
The one-second check

What each word means

Fourth: the number

Fourth is the ordinal form of four, just as third comes from three and fifth from five. It works in several ways:

Adjective (ordinal): She finished fourth in the race. / the fourth chapter
Noun (position): He came in fourth. / Today is the fourth.
Noun (fraction): Three-fourths of the class passed. (more common in American English; see below)
Adverb: Fourth, we need to consider cost. (also fourthly)

Forth: the direction

Forth is mainly an adverb. It points forward in space or time, or outward from a hidden place into view.

Forward or onward: They went forth into the world.
Out into view: The tree brought forth blossom.
Onward in time: from that day forth
In fixed phrases: back and forth, and so forth, hold forth, set forth

Forth is not used as a number or a noun in ordinary English. If you can replace the word with forward, onward or out, you want forth.

Pronunciation

Both words are pronounced FORTH in standard American, British and Australian English. In non-rhotic accents (most of England and Australia), the r is silent, so both sound like "fawth." There is no reliable spoken clue, so this is purely a spelling distinction.

Where the words come from

The two words are unrelated, which helps explain why their spellings differ.

Fourth comes from Old English fēortha, built on the word for four. As four settled into its modern spelling, the ordinal kept the ou to match.
Forth comes from Old English forth, meaning "forward, onward." It is related to forward and further, and similar words exist in other Germanic languages.

So despite sounding the same, they grew from different roots: one from counting, one from direction.

Fourth vs forth at a glance

	Fourth	Forth
Core meaning	Number 4 in order; one quarter	Forward, onward, out
Part of speech	Adjective, noun, adverb	Adverb
Related word	four	forward
Spelling clue	Contains four	Contains for (as in forward)
Typical phrases	fourth place, Fourth of July, fourth grade, fourth estate	back and forth, and so forth, set forth, hold forth
Swap test	Replace with "4th"	Replace with "forward" or "onward"

Phrases with "forth" (and what they mean)

Many of the most common errors happen inside fixed expressions. Every one of these uses forth:

Phrase	Meaning	Example
back and forth	to and fro; one way then the other	The ferry goes back and forth all day.
and so forth	and similar things; etc.	pens, paper and so forth
so on and so forth	emphatic "etc."	chores, errands, so on and so forth
set forth	to state or explain formally; to begin a journey	The report sets forth three options.
hold forth	to talk at great length	He held forth about cricket for an hour.
bring forth	to produce or reveal	The inquiry brought forth new evidence.
come forth	to appear or come forward	Witnesses came forth after the appeal.
put forth	to propose or offer	She put forth a strong argument.
go forth	to go out into the world	Go forth and do good work.
sally forth	to set out boldly (literary, humorous)	We sallied forth into the rain.
from this day forth	from now on	From this day forth, no more excuses.

Back-and-forth can also be a noun or adjective, usually hyphenated: After a lot of back-and-forth, we agreed on a date, or a back-and-forth debate.

"Forth" in names and places

You may also see Forth as a proper noun. The River Forth and the Firth of Forth are in Scotland, crossed by the famous Forth Bridge near Edinburgh. There is also a River Forth in Tasmania. These names have nothing to do with the number four.

Phrases with "fourth"

Phrase	Meaning
Fourth of July	US Independence Day (July 4)
fourth grade (US) / Year 4 (UK, AU)	the school year for children around 9 to 10
the fourth estate	the press or news media
fourth dimension	time (in physics); something beyond ordinary experience
fourth wall	the imaginary wall between actors and audience
breaking the fourth wall	a character addressing the audience directly
fourth down (US football)	the last of four attempts to advance the ball
a fourth (music)	an interval spanning four notes of a scale

The phrase "breaking the fourth wall" comes from theater, where a stage set usually has three walls and the audience looks through the missing fourth. It is now used for films, TV, novels and even advertising.

Grammar notes on "fourth"

Hyphens in fractions

When a fraction acts as an adjective before a noun, hyphenate it: a three-fourths majority, a one-quarter share. When it works as a noun, styles differ. Many American guides hyphenate spelled-out fractions in all positions (three-fourths of the vote), while some British publishers leave the noun form open (three quarters of the vote). Whichever you choose, keep it consistent within one document.

Verb agreement with fractions

With a fraction, the verb usually agrees with the noun that follows of:

Three-fourths of the cake was eaten. (cake is singular)
Three-fourths of the guests were late. (guests is plural)

The same logic applies to a quarter of.

"Fourth" vs "4th"

In formal prose, most style guides spell out ordinals from first to ninth: the fourth quarter, fourth place. Numerals such as 4th are common in dates, tables, addresses and informal writing (4th Avenue, the 4th of June). Note that the suffix is always -th for four: never 4rd or 4nd.

"Forth" vs "forward" vs "further"

Because forth is related to forward and further, it is natural to wonder whether you can swap them. Sometimes you can, but each has its own territory.

Forward is the everyday word for physical direction and progress: Step forward, Let's move the meeting forward. It also works as a verb (forward an email) and an adjective (a forward pass).
Forth is now mostly found in fixed phrases and in formal or literary writing. "Step forth" sounds solemn or old-fashioned, while "step forward" sounds normal.
Further means "to a greater degree or distance" or "additional": further information, walk further. For that distinction, see our guide to farther vs further.

In practice, if you are not using a fixed phrase like back and forth or set forth, the plain word forward is usually the better choice in modern writing. Forth adds a ceremonial tone, which suits wedding vows, speeches and historical fiction but can feel stiff in a business email.

Why proofreading software misses it

Because both fourth and forth are real words, a basic spell-checker will accept either one. Some grammar tools flag "back and fourth" because it is such a frequent error, but they are far less reliable with less common phrases like "set fourth" or "came forth in the race." Reading the sentence slowly, or reading it aloud while asking "is this a number?", is still the most dependable check.

24 example sentences

Everyday

Our flat is on the fourth floor, and the lift is always broken.
The dog ran back and forth along the fence, barking at the possums.
This is my fourth coffee today, and it's only eleven o'clock.
We packed towels, sunscreen, snacks and so forth for the beach at Glenelg.
My niece just started fourth grade in Columbus.
The swing creaked as it moved back and forth in the wind.

Workplace and email

"Please see the fourth attachment for the revised budget."
"After a lot of back-and-forth with legal, the contract is ready to sign."
The policy sets forth clear guidelines on remote work.
Our London office finished fourth in the regional sales rankings.
"In the meeting, Dev put forth a proposal to cut travel costs."
"We'll need laptops, monitors, cables and so forth for the new starters."

Academic

The fourth chapter examines the economic causes of the war.
The author sets forth a new theory of language acquisition.
Roughly three-fourths of respondents supported the reform.
Darwin's work brought forth decades of scientific debate.

News style

The Australian swimmer finished fourth, just outside the medals.
Investigators urged witnesses to come forth with information about the fire.
Fireworks lit up the National Mall on the Fourth of July.
Talks between the two unions went back and forth for weeks.

Literary and figurative

From that day forth, she never doubted herself again.
The knights rode forth at dawn.
Spring brought forth a riot of color in the gardens of Kent.
Grandpa held forth on the state of the railways until everyone fell asleep.

US vs UK vs Australia

The spelling rules are identical in all three countries: fourth for the number, forth for the direction. The differences are in which phrases people tend to use.

Fractions: "a fourth" vs "a quarter"

United States: Both a quarter and a fourth are common. Americans often say one-fourth or three-fourths in math class and in measurements.
United Kingdom: Quarter is strongly preferred. Three-quarters is the normal phrase, and three-fourths sounds distinctly American.
Australia: Like British English, Australians generally say a quarter and three-quarters.

School years

United States: Fourth grade for children around nine and ten.
United Kingdom: Year 4 in England and Wales (Scotland uses Primary 4 or P4). The older term fourth form survives in some independent schools.
Australia: Year 4 is standard across the states.

Dates

Americans often say the Fourth of July or July Fourth. In Britain and Australia, people typically say the fourth of July or write 4 July. The holiday itself is, of course, an American occasion.

Listing points

Fourthly (after firstly, secondly, thirdly) is common in British and Australian writing. Many American writers and editors prefer first, second, third, fourth without the -ly. Both are correct.

Common mistakes

❌ The kids ran back and fourth across the playground. ✅ The kids ran back and forth across the playground.

❌ We need chairs, tables, plates and so fourth. ✅ We need chairs, tables, plates and so forth.

❌ She came forth in the 400-meter final. ✅ She came fourth in the 400-meter final.

❌ He's in forth grade. ✅ He's in fourth grade.

❌ The committee set fourth its recommendations. ✅ The committee set forth its recommendations.

❌ We celebrate the Forth of July with a barbecue. ✅ We celebrate the Fourth of July with a barbecue.

❌ The ad breaks the forth wall. ✅ The ad breaks the fourth wall.

Memory tricks

The "four" inside "fourth"

Fourth has four in it. Cover the th and you are left with four. If your sentence involves counting, ranking or quarters, you want the word that contains the number.

"Forth" goes forward

Forth and forward both start with f-o-r. If you can swap the word for forward or onward, use forth: "go forward / go forth," "back and forward / back and forth."

Practice quiz

Choose fourth or forth.

The pendulum swung back and ______.
Australia finished ______ in the medal table.
The new manifesto sets ______ the party's priorities.
This is the ______ time I've reminded you to clean your room.
We bought bread, milk, eggs and so ______.
The scientist brought ______ new evidence at the conference in Edinburgh.

Answers

forth: back and forth means one way and then the other.
fourth: a position in a ranking.
forth: set forth means to state formally.
fourth: counting the number of times.
forth: and so forth means "and similar things."
forth: bring forth means to produce or reveal.

More homophones that fool spell-checkers

Fourth and forth are classic homophones: same sound, different spelling and meaning. If you want to strengthen your eye for this kind of trap, try past vs passed, their, there and they're, sight, site and cite and peek, peak and pique. Each one, like this pair, slips past spell-checkers because both spellings are real words.

The one-second check

Every time you type forth or fourth, glance at the word and ask: am I counting? If yes, look for the four and write fourth. If you are moving forward, carrying on a list or bringing something out, write forth. That quick question will keep "back and fourth" out of your emails for good.