on (at) first glance

Quick answer

Use "at first glance" to mean "based on an initial look." "On first glance" is nonstandard and sounds awkward in standard English.

At first glance = an initial impression or immediate observation.
On first glance is usually a literal-translation error; replace it with at first glance.
Alternatives by tone: "upon initial inspection" (formal/technical) or "at first sight" (more visual or literary).

Core explanation: why at, not on

Choose prepositions by whether the phrase names a moment or a surface. At marks a point in time or viewpoint (at noon, at that moment). On marks a surface or location (on the table, on Monday).

"At first glance" refers to the moment you form an impression. Using "on" treats "glance" like a surface and breaks the idiom.

If the phrase names a moment → use at (at first glance).
If the phrase names a surface or physical location → use on.
Quick test: replace "glance" with "moment." If "at moment" reads naturally, use at.

Wrong: On first glance, the software looked bug-free.
Right: At first glance, the software looked bug-free.

Real usage and tone

"At first glance" is neutral and fits emails, reports, and conversation. Pick an alternative for a specific tone.

Formal/work: "Upon initial inspection, the specimen meets the criteria."
Neutral: "At first glance, the budget looks balanced."
Casual: "At first glance, that looks awesome."

Work: Upon initial inspection, the component passed all tests.
School: At first glance, her answer seemed correct.
Casual: At first glance, that color suits you.

Memory trick: replace glance with moment

Swap "glance" for "moment." If "at first moment" makes sense, use at. You don't stand on a glance, so "on" will feel wrong.

Moment = at; surface = on.
When editing, highlight the phrase and test the swap quickly.
Quick rewrite:
Wrong: On first glance, the file was complete. →
Right: At first glance, the file was complete.

Hyphenation: when to hyphenate first-glance

Leave "at first glance" unhyphenated when it modifies the verb (adverbial): "At first glance, the chart trends upward."

Hyphenate only when "first-glance" forms a compound adjective before a noun: "a first-glance impression." Never hyphenate the whole prepositional phrase.

Adverbial (no hyphen): At first glance, the draft is good.
Compound adjective (hyphenate "first-glance"): a first-glance summary.
Avoid odd forms like "at-first-glance report"-rewrite instead.

Work - Wrong: We sent an at-first-glance report. (awkward)
Work - Right: We sent a first-glance summary. (clean)

Spacing and punctuation: commas and placement

If "at first glance" begins a sentence, follow it with a comma: "At first glance, the figures align." If it is parenthetical, set it off with commas: "The figures, at first glance, align."

Keep the phrase as three separate words; never jam them into one or insert extra hyphens.

Introductory: At first glance, ... → comma required.
Parenthetical: ..., at first glance, ... → commas recommended.
Spacing: write separate words; avoid "atfirstglance" or "at-first glance."

Wrong: Atfirstglance the chart looked linear.
Right: At first glance, the chart looked linear.
Right: The chart, at first glance, looked linear.

Try your own sentence

Test the whole sentence, not just the phrase. Context often shows whether the phrase fits and whether a comma is needed.

Grammar pitfalls and close relatives

Use the phrase with perception verbs (seem, appear, look, feel) or followed by a clause. Avoid forced passives that hide the impression.

Watch similar idioms: "on closer inspection" is correct; "on closer glance" is uncommon. "At first sight" is correct but carries a different nuance.

Use with verbs like seem, appear, look, feel.
Keep idioms intact: "on closer inspection" (correct); "on closer glance" (not common).
Drop unnecessary articles: prefer "at first glance" (not "at a first glance").

Wrong: On closer glance, we found the error.
Right: On closer inspection, we found the error.
School - Wrong: At a first glance, the hypothesis seemed true.
School - Right: At first glance, the hypothesis seemed true.

Examples you can copy: work, school, casual

Replace "on first glance" with "at first glance" and add punctuation. When you need more formality, use the formal rewrites shown.

Work - Wrong: On first glance, the merger looked beneficial to both companies.
Work - Right: At first glance, the merger looked beneficial to both companies.
Work - Wrong: On first glance the prototype met the specs.
Work - Right: At first glance, the prototype met the specs.
Work - Rewrite:
Formal: Upon initial inspection, the prototype met the specifications.
School - Wrong: On first glance I thought the student had answered correctly.
School - Right: At first glance, I thought the student had answered correctly.
School - Wrong: On first glance the essay answered the prompt.
School - Right: At first glance, the essay answered the prompt.
School - Rewrite: At first glance, the essay seemed to address the prompt, but it needed clearer examples.
Casual - Wrong: On first glance she seemed upset with me.
Casual - Right: At first glance, she seemed upset with me.
Casual - Wrong: On first glance that color suits you.
Casual - Right: At first glance, that color suits you.
Rewrite example: Wrong: On first glance the data was clear. → Better: At first glance the data looked clear; a deeper analysis revealed outliers.

How to fix your sentence in three quick steps

Use this checklist when you spot a possible preposition error.

Step 1: Find "on first glance" in your sentence.
Step 2: Replace "on" with "at." Add a comma if the phrase starts the sentence.
Step 3: If it still sounds off, swap to "upon initial inspection," "at first sight," or rewrite to remove the phrase.

Work - Wrong: On first glance the deliverable met all requirements.
Rewrite: At first glance, the deliverable met all requirements.
School - Wrong: On first glance her lab report looks complete.
Rewrite: At first glance, her lab report looks complete.

Similar mistakes to watch for

Fixing "on first glance" is a quick win. Watch other preposition swaps that produce awkward idioms.

Wrong: "On closer glance" →
Right: "On closer inspection" or "Upon closer inspection."
Wrong: "On first sight" →
Right: "At first sight."
Wrong: "At a first glance" →
Right: "At first glance" (drop the article).

Wrong: On closer glance, we found discrepancies.
Right: On closer inspection, we found discrepancies.
Wrong: On first sight, I loved the poem.
Right: At first sight, I loved the poem.

FAQ

Is it incorrect to say "on first glance"?

Yes. "On first glance" is considered nonstandard. Use "at first glance" in standard English.

When should I use a comma after "at first glance"?

Place a comma when the phrase begins a sentence: "At first glance, the results look good." If it is parenthetical, set it off with commas: "The results, at first glance, look good."

Can I use "at first sight" instead?

"At first sight" is correct but more visual or literary. Use "at first glance" for general initial impressions.

How do I make the phrase more formal?

Use "upon initial inspection" or "upon initial review" for formal or technical contexts.

Is "first-glance" hyphenated?

Hyphenate when it functions as a compound adjective before a noun: "a first-glance impression." Do not hyphenate the full prepositional phrase.

Quick checklist before you hit send

Search your document for "on first glance" and replace it with "at first glance." Add a comma if it starts the sentence. If you need higher precision or formality, choose "upon initial inspection" or rewrite the sentence.