comparison · LoupeKit vs Designer Tools
LoupeKit vs Designer Tools: which one should you install?
Designer Tools has been shipping since 2018 and knows exactly who it is for: someone with a mockup open and a browser beside it. Rulers, smart guides, stored guidelines, grid overlays and an image overlay for comparing the built page against the comp. It is the cheapest tool on this list and the most focused, and for pixel-matching work that focus is the feature.
Matching a built page to a mockup: Designer Tools. Reading what the page already is: LoupeKit.
Designer Tools
Free tier · low monthly tiers · Chromium
Measurement and alignment first: rulers, element comparison, distance measurement, smart guides and saved guidelines on the free tier, grid overlays and mockup comparison a tier up, an accessibility inspector above that. Dark mode, sixteen-plus languages, keyboard shortcuts, and a branding inspector listed as coming soon.
LoupeKit
Free tier · nine surfaces · Chromium and Firefox
Measurement is one of sixty-three tools rather than the point of the product. The weight is on reading: what the page is built with and why the tool thinks so, its tokens as painted, diagnostics that rank what to look at rather than waiting to be asked, SEO, accessibility, and a score for how much of the markup reads as generated.
Feature by feature
5 of 10 rows differ · they are the shaded onesWhere LoupeKit stops, and why
1 of the rows above · each one is a decision- Interface in many languages
- The panel is English only. Translating it is not the work — keeping sixty-three tools, their hints and every refusal sentence correct in eight languages is, and a half-translated panel that falls back mid-sentence is worse than one that does not pretend.
The same jobs, side by side
Match a built page against a mockup
DESIGNER TOOLS An image overlay made for it, plus stored guidelines that survive a reload.
LOUPEKIT A comp overlay with four modes - opacity, a 50% inversion that turns every match flat grey, a wipe, and a measured difference - a rule drawn round the comp’s own rectangle, and guides pinned from the rulers that come back on that site after a reload.
Measure spacing between elements
DESIGNER TOOLS Rulers and smart guides, on the free tier. Its strongest work.
LOUPEKIT Distances to neighbours and to each viewport edge, from the inspector.
Put a column grid over the page
DESIGNER TOOLS Customisable overlays, on a paid tier.
LOUPEKIT Columns, gutters and baseline, free, measured against a 1440px reference.
Find out what the page is built with
DESIGNER TOOLS A branding inspector is listed as coming soon.
LOUPEKIT 1700 technologies with the evidence for each.
Get the page’s type and colour scale as a file
DESIGNER TOOLS Not offered.
LOUPEKIT A Tailwind theme, a CSS custom-property sheet or a W3C token file.
Pay once instead of monthly
DESIGNER TOOLS Monthly or yearly subscription.
LOUPEKIT A monthly plan or a single lifetime payment, both carrying the same features.
Pick Designer Tools if
If your day is spent matching a build to a comp. Smart guides that snap to the elements they are measuring are the part we do not have, and the measurement work around them is better than ours because it is the whole product rather than one tool in it. Persistent guidelines used to be on this list and are not any more - ours are pinned from the rulers and come back per site after a reload - so the difference there is depth rather than absence. It is also the only tool here with an interface in sixteen-plus languages, which matters if English is not the one you want to work in.
Pick LoupeKit if
If the page came from somebody else and the questions are about it rather than about its alignment: what it runs, what it ships, what it fails, and how much of it reads as generated.
Run both
Sensible for a designer-developer pair: one person matching the comp, the other reading the build. They overlap on measurement and nowhere else.
TWO BUILDS9 browsers
Chromelisting in reviewFirefoxlisting in reviewBravelisting in reviewOperalisting in reviewEdgelisting in review4 moreChromium browsers: Arc, Vivaldi, Chromium, Opera GXthe Chrome buildCHECKED 17 AUGUST 2026
Every figure about Designer Tools on this page was checked on that day against designer.tools, including its pricing page, and its Chrome Web Store listing, and nothing here is quoted from a review. Where a fact is not published anywhere we can point at, the table says so rather than estimating it. Products change; if something above is out of date, write to [email protected] and it will be corrected.
Designer Tools and every other product name on this site are the trademarks of their own owners. LoupeKit is not affiliated with, endorsed by or sponsored by any of them.