'ten fold' written as one word

Writers often wonder whether to write tenfold as one word, with a hyphen, or as two words. Quick rule: write tenfold, twofold, threefold when the number is spelled out; use a hyphen with numerals (10-fold, 2-fold) for compact data or technical labels.

Below are clear rules, paired wrong/right examples, real-use samples for work and school, and copy-paste rewrites you can use immediately.

Quick answer

Write tenfold, twofold, threefold (one word) with spelled-out numbers. Use a hyphen with numerals (10-fold, 2-fold) in tables or technical copy. Don't use the two-word form (ten fold) to mean "ten times."

Spelled-out numbers → closed compound: tenfold, twofold.
Numerals → hyphen is clear: 10-fold, 3-fold.
Avoid: ten fold, two fold (as multipliers).

Core rule, fast

When number + fold denotes a multiplier, close the compound: tenfold, twofold. Use a hyphen only when the number is a numeral (10-fold). If "tenfold" looks odd in context, rephrase as "ten times" or "by a factor of ten."

Correct: tenfold increase; sales rose threefold.
Numeric charts: 10-fold improvement; 5-fold difference.
Wrong: the profits rose ten fold.

Hyphenation & spacing

Style guides vary, but a simple, practical approach works for most writing: keep spelled-out numbers closed and hyphenate numerals. A space (ten fold) breaks the compound and reads as an error.

Use 10-fold or 3-fold in tables, charts, figure captions, and labels.
Use tenfold or threefold in running prose and narrative sentences.
If a closed form feels clumsy, rewrite: "ten times" or "by a factor of ten."

Grammar: part of speech and traps

Tenfold functions as an adjective (a tenfold increase) or an adverb (profits increased tenfold). Treat it as a closed compound in both roles. The verb form "to tenfold" is awkward; prefer "increase tenfold" or "multiply by ten."

Adjective: a twofold benefit.
Adverb: sales rose threefold.
Avoid inventing forms like "tenfolded."

Examples: common wrong/right pairs

Use these pairs to fix errors quickly. The wrong example shows the typical mistake; the right example is the preferred fix.

Wrong: The company's revenue increased ten fold in Q4.
Right: The company's revenue increased tenfold in Q4.
Wrong: We saw a two fold rise in customer complaints.
Right: We saw a twofold rise in customer complaints.
Wrong: There was a ten - fold improvement after the redesign.
Right: There was a 10-fold improvement after the redesign.
Wrong: Her efforts will be rewarded ten fold.
Right: Her efforts will be rewarded tenfold.
Wrong: We recorded a three fold jump in engagement.
Right: We recorded a threefold jump in engagement.
Wrong: The dataset shows a 5 fold increase.
Right: The dataset shows a 5-fold increase.

Try your sentence

Test the expression in context rather than as an isolated phrase. Context usually makes the correct form obvious.

Grouped examples: work, school, casual

Short, realistic examples for different contexts. If you see a space between the number and "fold," change it.

Work: Slide headline: Conversion improved 10-fold after funnel changes.
Work: Report: The campaign delivered a tenfold increase in qualified leads.
Work: Technical note: We observed a twofold reduction in latency after the patch.
School: Lab report: Yield increased threefold when reagent X was doubled.
School: Essay: The policy has a twofold effect on housing and transport.
School: Abstract: Error rates dropped 10-fold after recalibration.
Casual: Text: My followers went tenfold after that post!
Casual: Tweet: Twofold jump in engagement-can't believe it!
Casual: Chat: Tastes better threefold with that extra spice.

Rewrite help: quick fixes you can paste in

If tenfold sounds clunky or the sentence needs to be more formal, use these natural rewrites.

Original: "Sales were up ten fold." →
Rewrite: "Sales increased tenfold." or "Sales grew by a factor of ten."
Original: "There will be a two fold change in budget." →
Rewrite: "The budget will change twofold." or "The budget will double."
Original: "We need to fold the paper tenfold to get the shape." →
Rewrite: "We need to fold the paper into ten layers to get the shape."
Original: "A 5 fold difference was observed." →
Rewrite: "A 5-fold difference was observed." or "The difference was fivefold."
Original: "This gives a three fold advantage to Group A." →
Rewrite: "This gives Group A a threefold advantage." or "Group A's advantage is three times greater."

Quick checklist & memory tricks

Make this a fast editing habit: glance, fix, rephrase.

Checklist: (1) Spelled-out number? → close the word (tenfold). (2) Numeral? → consider 10-fold. (3) Still awkward? → rewrite as "ten times" or "by a factor of ten."
Mnemonic: "Spell it → stick it" (spell-out numbers stick to "fold").
Mnemonic: "Digit → dash" (use a dash with digits: 10-fold).

Similar mistakes to watch for

Other compound errors follow the same logic: either close the compound or hyphenate with numerals and check meaning.

upfront vs up front - use upfront as an adjective (an upfront payment).
altogether vs all together - altogether = entirely; all together = in one place.
two-thirds - hyphenate as a compound adjective before a noun: a two-thirds majority.
high-level vs high level - hyphenate when the phrase modifies a noun: a high-level summary.

FAQ

Is it "tenfold" or "ten fold"?

Use tenfold (one word) when the number is spelled out. Ten fold (two words) is incorrect for "ten times."

Can I write 10-fold with a hyphen?

Yes. 10-fold is common and clear in tables, charts, and technical copy. In running prose, tenfold is preferred.

Should I hyphenate "twofold" before a noun?

No. If the number is spelled out, write twofold without a hyphen: a twofold preference. With digits, 2-fold is acceptable in technical contexts.

Is "tenfold" ever a verb?

It appears rarely as a verb, but that use is awkward. Prefer "increase tenfold" or "multiply by ten."

Which style guide should I follow?

Guides differ. A practical default works for most writing: spelled-out numbers → closed form (tenfold); numerals → hyphen (10-fold). Follow your organization's preferred style when specified.

Need a quick check?

Paste the sentence into a grammar tool or run this checklist: spelled-out number → one word; numeral → 10-fold; if clumsy, rewrite as "ten times" or "by a factor of ten."