Translation plagiarism checker for Spanish papers
Translating an English source into Spanish and handing it in without citing it is plagiarism: the ideas, the structure and the evidence belong to someone else. A regular checker misses it, because not a single word is the same. This one compares the Spanish text with sources in English, sentence by sentence, and shows you which sentences are a possible translation.
Open the free checkerWhat a translated sentence looks like
English source
The industrial revolution transformed the economic structure of Europe in the nineteenth century.
Spanish paper
La revolución industrial transformó la estructura económica de Europa en el siglo XIX.
No word is identical, but almost every important word has a twin in the other language, and they come in the same order. That is the trace the checker follows.
How it finds a possible translation
Each sentence of the paper is compared with each sentence of the English sources by what survives a translation:
Cognates
Words that keep their root across languages: revolution and revolución, structure and estructura.
Numbers and centuries
Dates, figures, acronyms and centuries (nineteenth century and siglo XIX) survive any translation.
Proper names
People, places and institutions appear in both texts.
Order of ideas
A translation keeps the order of the original, so neighboring sentences are checked too.
A sentence with many of those elements in common is marked as a possible translation, and the sentences around it are reviewed in more detail. Possible translations are shown apart and are not counted in the similarity percentage: two texts about the same topic can share names and dates, so the flag is a lead to review, not a verdict.
Which English sources it compares with
- Abstracts and academic articles in English found in the academic databases.
- English web pages found by the web search.
- The English version of each encyclopedia article found on the same topic.
- Any English source you add yourself (up to 5 PDF, Word or text files).
For Spanish teachers: check the source you suspect
If a paper reads like a translation of an article you know, add that article and the checker compares the two sentence by sentence:
- 01Open the free checker and upload the paper (PDF or Word) or paste its text.
- 02Tap “Your sources” and add the English article as a PDF, Word or text file.
- 03Run the analysis. Sentences translated from that article appear as possible translations, next to the sentence of the source they match.
Students can do the same before handing in a paper: if a sentence comes from an English source, cite it. The report gives you the APA 7 reference of every source it finds; check your instructor's rules for translated quotations.
How accurate it is, measured
41.6%
of 9,328 sentences translated by professionals at the European Parliament were flagged, with 0.00% false flags against 400 unrelated English sentences.
32 of 32
translated passages flagged on our own bank of academic texts (an easier test), and 0 of 16 unrelated ones.
Parliamentary speech translated by professionals keeps few cognates, which makes it the hard case; academic writing keeps many more. Even so, read the numbers as they are: a flag is strong evidence, and the absence of a flag does not prove a text is original.
What it cannot see
- A translation of a source it never finds. Adding the source you suspect solves this.
- A loose translation that changes the order, the names and the figures, or a free summary of the source.
- Papers written in English: this check is for Spanish documents compared with English sources.
Frequently asked questions about translation plagiarism
Can a plagiarism checker detect a text translated with Google Translate?
It does not detect the tool: it detects that a sentence in Spanish lines up with a sentence of an English source, whoever or whatever translated it (a person, Google Translate, DeepL or a chatbot). The comparison relies on what survives a translation: cognates, numbers, acronyms, proper names and the order of the ideas. It only works with sources it finds or that you add, so adding the English source you suspect is the most reliable way.
Are translations counted in the similarity percentage?
No. Possible translations are marked apart, like possible paraphrases, and are not added to the percentage. The percentage only counts verbatim and near-verbatim copying, which can be checked word by word.
How accurate is it?
Measured on 9,328 sentence pairs from the European Parliament translated by professionals (with few cognates), 41.6% of the translated sentences were flagged and 0.00% of 400 unrelated English sentences were. On our own bank of academic passages, an easier test, it flagged 32 of 32 translated passages and 0 of 16 unrelated ones. A flag is strong evidence worth reviewing; no flag does not prove that a text is original.
Does it work the other way, from Spanish into English?
No. It is built for documents written in Spanish and compares them with sources in English. An English paper translated from a Spanish source is not covered by this check.
Is it free? Do I need an account?
Yes. You can analyze your documents without paying and without creating an account. The analysis runs on your own device, so there is no usage limit due to server costs.
Is the paper uploaded to a server?
No. The file is read and compared inside your browser. To look for sources, only isolated phrases and keywords are sent to the search services, never the document; the details are in the privacy section of the plagiarism checker and in our privacy policy.