Formal vs Informal Writing: A Practical Guide
What actually makes writing formal or informal? Not what you were taught in school. Here's the real breakdown with examples.
· 4 min read
School teaches a simple rule: formal writing uses long words and no contractions, informal writing uses short words and contractions. This rule is wrong.
Real formality is a bundle of eight specific choices. Get them right and your text lands at the correct register without effort. Get them wrong and you produce text that feels stilted, condescending, or inappropriate.
Here's what actually separates formal from informal.
1. Contractions
The most obvious marker. Contractions signal casualness instantly.
| Formal | Informal |
|---|---|
| do not | don't |
| will not | won't |
| you are | you're |
| it is | it's |
One caveat: modern business writing frequently uses contractions even in professional contexts. "Professional" and "formal" aren't the same register. Formal academic writing avoids contractions. Professional email increasingly doesn't.
2. Personal pronouns
Formal writing minimizes "I" and "you". Informal writing uses them freely.
Formal: "One should consider the implications before proceeding." Professional: "You should consider the implications before proceeding." Casual: "Think about the implications first."
The distance from the reader increases as the register rises. Academic writing often goes further — removing the person entirely: "The implications should be considered."
3. Sentence structure
Formal writing uses longer sentences with more subordinate clauses. Informal writing uses shorter ones, often fragments for effect.
Formal: "Although the initial findings were inconclusive, further investigation, conducted over the subsequent six months, revealed a consistent pattern of anomalies that warrants further study."
Informal: "The first round didn't show much. Six more months of work revealed a pattern. Worth looking into."
Same content. Very different feel.
4. Vocabulary level
This is where the "long words" rule comes from, and it's partially right. Formal writing favors Latinate vocabulary (often longer, more abstract). Informal writing favors Germanic vocabulary (shorter, concrete).
| Latinate (formal) | Germanic (informal) |
|---|---|
| commence | start |
| terminate | end |
| consume | eat |
| purchase | buy |
| assist | help |
| require | need |
| sufficient | enough |
The rule breaks down when you overdo it. "One must terminate one's engagement with the comestibles prior to commencing the journey" is not formal — it's absurd. Register has a ceiling.
5. Hedging and certainty
Formal writing hedges claims. Informal writing states them directly.
Formal: "The results suggest that the intervention may have contributed to the observed improvements." Informal: "The intervention probably caused the improvements." Very informal: "Yeah, the intervention worked."
Academic and scientific writing hedges heavily because overclaiming damages credibility. Casual writing hedges rarely because over-hedging sounds evasive.
6. Connectors between ideas
Formal writing uses explicit logical connectors. Informal writing lets connections stay implicit.
| Formal | Informal |
|---|---|
| Furthermore, | Also |
| Nevertheless, | Still |
| Consequently, | So |
| In addition to this, | Plus |
| With regard to | About |
Note that some formal connectors are so overused by AI that they've become tells. "Furthermore" at the start of a sentence reads as machine-generated more often than not.
7. Direct vs indirect statements
Formal writing prefers indirect, diplomatic phrasing. Informal is direct.
Formal: "It would be appreciated if you could review the proposal at your earliest convenience." Professional: "Could you review the proposal when you get a chance?" Casual: "Can you look at the proposal?"
Same request, three distances. Each works in its context. None works in someone else's.
8. Rhetorical strategies
Formal writing uses evidence, citations, logical structure. Informal uses examples, anecdotes, direct appeals.
This is the deepest layer. It's not about word choice — it's about what kind of argument you're making. A formal argument says "the evidence shows". An informal argument says "here's what happened to me".
Choosing the right register
The right register isn't about being smart or lazy. It's about matching your context:
- Academic papers, grant applications, legal documents → formal
- Client proposals, business reports, LinkedIn articles → professional (between formal and informal)
- Marketing copy, blog posts, emails to colleagues → conversational (informal but polished)
- Text messages, tweets, Slack → fully casual
Mismatching produces cringe. A casual cover letter gets rejected. An academic Slack message gets mocked. Calibrate first, write second.
When a tool helps
Adjusting register manually across a long document is tedious and error-prone. A good rewriter handles all eight levers simultaneously.
ShiftText gives you five tone presets that each calibrate these eight variables together. Pick "professional" and contractions expand, sentences lengthen moderately, hedging increases, Latinate vocabulary appears where appropriate. Pick "casual" and everything swings the other way.
Use the tool for the first pass. Use your editorial judgment for the final call.
The real test
After you've written something, ask: would I say this out loud to my audience? If the answer is yes, you've matched the register. If it would feel weird coming out of your mouth, your register is off.
Speaking is informal by default. Writing is formal by default. Great writing closes the gap when it should — and keeps it open when it needs to.