Translate an Entire Web Page Side by Side: Chrome Translate vs AI Bilingual Extensions

Bilingual page translation shows the original text and its translation together on the same page, usually with each translated paragraph directly under its source paragraph. Most built-in translators replace the page. A bilingual view keeps the original, so you can glance down when a phrase looks odd, check a number, or learn the language as you read.

In Copilotly, you right-click a page and choose Translate this page with Copilotly. Each heading, paragraph, list item, quote, caption and table cell gets its translation inserted beneath it, in one of 33 target languages. A bar at the top switches between Both, Translation and Original. Free accounts get 3 full pages a day and Pro gets 200. The details are on the page translation feature page.

This guide is a neutral comparison, not a sales page. It covers Chrome's built-in translate, AI extensions, and how to judge translation quality yourself, plus the failure modes of translating long or dynamic pages. I did not run a benchmark across models or tools, and I say so where it matters.

Who wants side-by-side

• Language learners reading real articles with the source one glance away.
• Researchers and students who need to quote the original, not the translation.
• Shoppers checking sizes, delivery times and return terms on foreign stores.
• Remote teams reading documentation in another language where code and terms must stay intact.

Chrome's built-in translate is free, quick and good enough for the gist. An AI extension is worth adding when you want the original kept beside the translation, or when you want to ask questions about the page afterward.

What Chrome documents

Chrome's translate help page says you can translate a page from the address bar icon or by right-clicking it, translate just a selection with "Translate selection to [Language]", and manage settings: whether to offer translation, your preferred language, and lists of languages to translate automatically or never offer to translate (as of November 2026). The page does not list supported languages, and it does not say whether the translated text replaces the original. It does not describe a side-by-side view.

For developers, Chrome also documents a Translator API that runs translation on the device with AI models built into the browser. Per that page, the model downloads the first time a site uses it, it works on desktop Chrome and not on mobile, and it is listed as supported in Chrome 138 and Edge 148, with Firefox and Safari not supported. The page was last updated May 20, 2025. This tells you on-device translation exists. It does not tell you what any particular extension uses.

The comparison

Dedicated translation extensions

Specialist extensions such as Immersive Translate are built around this single job. As of November 2026 I have not tested them head to head and will not claim a comparison. Expect a specialist to offer more translation engines to choose from, per-site rules for automatic translation, and more layout control. If translating web pages is all you need, compare one before you settle. What Copilotly adds is that the same extension also chats with your files, summarizes videos and rewrites text in place. See the Sider alternative page for how it compares with other all-in-one sidebars.

1. Install the extension from the download page.
2. Right-click anywhere on the page and choose Translate this page with Copilotly. Right-click the page body, not a link or image.
3. Watch it fill in. A bar appears with a progress indicator, a selector labelled "Translate into" and a Stop button. Translations are inserted below each original as they arrive.
4. Choose how to read it. When the bar says "Page translated", pick Both, Translation or Original.

The three views

• Both is the default: original with translation beneath. Use it when accuracy matters or you are learning.
• Translation hides the original so the page reads as if written in your language. Use it for the gist or for reviews and comments.
• Original hides the translation without discarding it. Use it to copy a source sentence exactly into a search or citation.

Language, stopping and removing

The target language starts from your browser language or the last one you picked, and is remembered between pages. It never translates a page into the language it is already in. Change the selector and the page translates again. Stop halts a run in progress. The cross removes the translation and restores the page. The translation is not saved with the page, so reloading the tab clears it, and it exists only in your browser, never on the website itself.

What it translates and skips

It targets readable content: headings, paragraphs, list items, quotes, captions and table cells. It skips code blocks, form fields and text boxes, scripts, navigation bars and footers, and anything you are editing, so code samples and interface labels stay intact.

I cannot honestly tell you one model is best for every language pair, because I did not benchmark them and the vendors do not publish a pair-by-pair ranking I can cite. What I can give you is a repeatable five-minute test, so you decide on your own languages and your own content.

Two product facts first. Whole-page translation in Copilotly is a Copilotly service with its own daily allowance, and the feature page does not document a model picker for it. So the test below uses the chat, where you can switch models, to compare. The model pages for Gemini, ChatGPT, Claude and DeepSeek describe how each family behaves, which can guide which to try first for your language pair.

Step 1: build a 6-sentence test paragraph

Pick text in the source language that includes: an idiom, a sentence with a negation ("not unless"), a number with a unit and a date, a proper name, a formal or polite register sentence, and a table row or list item. The feature page's own samples show the idea:

These two lines are illustrative samples from the feature page, not my test results.

Step 2: run the same text through each candidate

Paste the paragraph into the chat with this prompt, switching the model in the picker between runs:

Translate the following [source language] text into [target language]. Keep the same number of sentences. Keep names, numbers and units unchanged. Do not summarize or omit anything. After the translation, list any phrase you were unsure about.

Step 3: score each result on six points

Run it on two or three paragraphs from your real material. If you read both languages a little, the Both view makes this check fast. If you read neither, ask a bilingual friend to check one paragraph.

What tends to differ

Differences usually show up in rarer language pairs, informal speech, domain jargon, and long inputs. I will not name winners. If two models disagree on a sentence, that is the sentence to verify against a human source.

Translation runs block by block, so how a page is built affects the result.

Right-to-left languages

Arabic and Hebrew are among the 33 target languages. If the layout looks odd, the Translation view is usually the cleanest to read.

Failure modes specific to AI translation

• Fluent but wrong. AI translation reads naturally, which makes errors harder to spot than the stilted output of older engines. Check numbers, dates, units, names and negations.
• Silent omission. A language model can drop a clause or merge two sentences without flagging it. The Both view is the defense: glance at the source and see whether the translation covers it.
• Inconsistent terms. Because pages are translated in batches, the same technical term may be rendered two ways on one page.
• Idioms and brand names. Literal rendering of an idiom, or translating a product name that should stay.
• Cut-off pages. A long page may stop at the 400-block cap with no obvious sign unless you scroll to the end.

Checking a long page was fully translated

Scroll to the very end in Both view and confirm the last paragraph has a translation under it. If not, scroll there, wait for any content to load, and run again. Re-running the same page in the same state is not charged twice.

Copilotly counts whole-page translation per page, not per paragraph: 3 full pages a day on Free and 200 a day on Pro. The first batch carries the charge, and translating the same page again in the same state does not charge you twice. When you reach the Free limit, the bar says so and offers Pro. Pro is $6.99 a week, $19.99 a month or $149.99 a year, with a 7-day trial for first-time subscribers (see pricing).

What a key does and does not change

If you connect your own API key through bring your own key, chat requests run on your provider account. Per the feature page, whole-page translation is a Copilotly service with its own daily allowance, so a key does not lift that limit.

Why LLM translation can be cheap per page, and where it is not

This is an illustration of the economics, not how Copilotly bills. Assume a 3,000-word article, roughly 4,000 tokens at about 0.75 words per token. Translation sends that much in and gets about the same amount out, so about 4,000 input tokens and 4,000 output tokens. At OpenAI's gpt-5-mini list price of $0.25 per million input tokens and $2.00 per million output tokens (OpenAI API pricing, as of November 2026), that is 4,000 x $0.25 / 1,000,000 = $0.001 for input plus 4,000 x $2.00 / 1,000,000 = $0.008 for output, about $0.009, under a cent. Non-Latin scripts can use more tokens for the same meaning, so the real number varies. The point is that per-page cost is low on a small model, and it rises with page length and with the model's price.

Where limits bite

• Many pages a day. Three Free pages go fast if you research in a foreign language. Pro's 200 a day is generous for most people.
• Very long pages. The 400-block cap, not the daily count, is the limit. Split the work.
• Selection translate is separate. Select text and use Translate in the selection toolbar, which offers twelve languages and is counted as an ordinary message, not a page.

Page translation or selection translate?

The text blocks being translated are sent to the AI model that writes the translation. That is how it works, per the feature page, and it means you should not translate pages that show private information you would not paste into an email: a bank statement, a medical portal, an internal document.

Where the translation lives

The translation exists only in your browser tab. It does not change the website for anyone else, does not create translated pages that search engines can index, and disappears when you reload. If you run a site and want real multilingual pages, read Google's guidance on managing multi-regional and multilingual sites.

On-device vs cloud

Chrome's Translator API page describes client-side translation that avoids uploading content to a hosted translation service. If you must translate sensitive text and want it to stay on your machine, that kind of on-device tool, or a human translator under an NDA, is the right choice, not an AI sidebar. Check any tool's privacy policy for what it sends.

Quick rule

If you would not email the text to a stranger, do not run it through a cloud translator. Public articles, product pages and documentation are fine.

For a sentence or two, you do not need a whole page. Select the text and use Translate in the selection toolbar. It works on text on any page, and the result panel lets you copy it or apply it. It offers twelve languages and counts as an ordinary message, not a page.

Replying in another language

Select your draft and ask for the translation, then check it with a back-translation: translate the result back into your language in a fresh chat and compare. If the meaning drifted, simplify your source sentence and try again.

Translate this email into [target language]. Keep it [formal / friendly]. Use the polite form of "you". Keep names, dates and numbers unchanged. Afterwards, give me a one-line English back-translation so I can check the meaning.

Tone after translating

A translation can be correct and still sound off. Ask for a tone change: "Make this sound less blunt but keep every fact." For wording variations within one language, the paraphrasing tool is a free option that needs no account.

Ask questions about the translated page

After translating, press Alt+C to open the sidebar and ask about the page: which fees apply, what a section means, what the deadline is. Use web search to check a claim against other sources.

Use machine translation to understand a document and a qualified human to rely on one. For contracts, medical records, immigration paperwork or anything with legal or financial consequences, treat the translation as a reading aid. The American Translators Association is one place to find a professional translator. Rules vary by country and by who will accept the document, so ask the receiving office what it requires.

Before you rely on a translation

1. Read in Both view and keep the original visible.
2. Check every number, date, unit, currency and name against the source.
3. Search for negations (not, unless, except, only) and confirm each one carried over.
4. Scroll to the end and confirm the last block was translated and nothing was cut off at the 400-block cap.
5. Re-run after any content that loaded late.
6. Compare two models on the three most important paragraphs. Where they disagree, verify with a human or the original source.
7. Ask the chat: "List any sentences where the meaning is ambiguous in the source."
8. Back-translate the key clauses in a new chat and compare the meaning.
9. Quote and cite from the Original view, never from the translation.
10. For anything binding, get a professional translation.

Quick decision guide

To try it, install the extension, open a foreign-language article and use the 3 free pages a day to judge whether the output reads well for your languages. The Monica alternative page covers other all-in-one sidebars, and the AI tools by profession guide has more workflows.