First name what is fuzzy: time, number, quantity, estimate, or the whole situation. Then choose an approximation phrase that matches the context and register.

If you say the walk takes exactly 17 minutes when you have never timed it, English is not impressed by the confidence. Approximation is not vagueness; it is accurate honesty about how exact your information really is.

About: an everyday way to remove false precision

Cambridge’s grammar guidance explains that about can make numbers, quantities and times less exact.

That makes it useful in ordinary answers:

  • “There were about 20 people.”
  • “It takes about half an hour.”
  • “I’ll be there at about six.”
  • “We need about two litres.”

Nothing here promises a secret tolerance. About 20 does not mean “within exactly two people.” The acceptable amount of fuzziness depends on the situation and what the speaker actually knows.

Around: another common choice for approximate times and numbers

Around also has an approximation use. Cambridge notes this meaning in its grammar guidance on around and round.

In many everyday situations, about and around overlap:

  • “Let’s meet around seven.”
  • “The room holds around 50 people.”
  • “It’s around three kilometres from here.”

Do not turn that overlap into a fake rule that they are interchangeable in every sentence. The useful beginner move is simpler: for a normal approximate time or number, both are worth recognizing and practising.

Roughly: make the estimate feel like an estimate

Roughly is especially useful when you want to signal that a figure is a broad estimate or calculation rather than an exact value.

  • “The route is roughly 30 kilometres.”
  • “Roughly half the group chose the earlier slot.”
  • “It took roughly two hours.”

That does not mean roughly always describes a larger error range than about or around. There is no useful universal percentage chart here. If someone gives you “about = ±5%, roughly = ±10%,” gently place that chart in the recycling bin.

Approximately: useful when the register is more formal

Approximately often fits reports, technical explanations, instructions, research-style summaries, or contexts where the tone is more formal:

  • “The container holds approximately 2.5 litres.”
  • “The procedure takes approximately 45 minutes.”
  • “The two locations are approximately 12 kilometres apart.”

That does not make approximately “better English.” Telling a friend “I’ll arrive at approximately 7 p.m.” is grammatical, but it can sound more formal than the situation needs. Your friend asked when you are coming over, not for a satellite launch window.

More or less has two jobs you should not mix up

Cambridge’s grammar page on more or less shows that it can mean approximately, but it can also mean something closer to mostly, nearly, or in general.

Job 1: approximate quantity or number

  • “There were 50 people, more or less.”
  • “It cost £100, more or less.”

Job 2: mostly or nearly

  • “The project is more or less finished.”
  • “I more or less understand what happened.”

In the second group, there is no hidden number that you need to calculate. The phrase describes the overall state.

Precision Repair Diagnostic

Read each sentence and decide what is happening before opening the answer.

1. “The walk takes 17 minutes.” The speaker has never timed it and only knows it is usually somewhere near that length.

FALSE PRECISION. The sentence is grammatically valid, but it sounds exact. If the speaker intends an estimate, “It takes about 15–20 minutes” or “It takes around 17 minutes” makes the uncertainty visible.

2. “Let’s meet around six.”

NATURAL EVERYDAY APPROXIMATION. Around tells the listener that six is the center of the intended time, not necessarily an exact appointment at 18:00:00.

3. “The sample contained approximately 2.5 litres.”

FORMAL REGISTER FIT. If the context is technical and the value itself is approximate, approximately is a natural choice. If 2.5 litres is an exact measured value, do not add approximation just because the sentence sounds scientific.

4. “I’ll get there approximately seven-ish.”

MIXED REGISTER / REDUNDANT APPROXIMATION. The meaning is understandable, but formal approximately plus very informal -ish is an awkward combination for most ordinary contexts. Say “around seven,” “about seven,” or, informally, “seven-ish.”

5. “The redesign is more or less finished.”

NON-NUMERIC MORE OR LESS. Here the phrase means something like “mostly/nearly finished.” Replacing it with “approximately finished” would not preserve the natural meaning.

Do not approximate something that is actually exact

Approximation is useful when your information is genuinely approximate or when exact precision is unnecessary.

  • “The train leaves at 7:12.” — useful if that is the actual scheduled time.
  • “I’ll arrive at around seven.” — useful if your arrival time is flexible or uncertain.

The goal is not to sprinkle about over every number. The goal is to match your language to the precision you really have.

Four-context approximation drill

Take four facts from your own day and say them aloud:

Then ask one final question: Do I actually know this exactly? If yes, give the exact value. No approximation phrase is required.

Optional: practise approximate answers aloud

After doing the drill manually, you can choose a speaking-practice path in FunFluen and practise giving short approximate answers aloud. The topic is not preloaded, so bring your own examples.

Approximation is accurate honesty

The useful choice is not “Which synonym is best?” Start one step earlier: what is actually fuzzy?

For ordinary times and numbers, about and around are excellent words to know. Roughly can foreground an estimate. Approximately often fits a more formal register. More or less needs a meaning check because it can also mean mostly or nearly.

No secret percentages. No spreadsheet costume. Just language that is as precise as your information deserves.

For more ways to turn real communication into active practice, explore media-based language learning.