CAT Tools: Computer-Assisted Translation Explained

Chidinma Egwuogu
19 Jul 2023

10 min. read


Translation may seem like a strictly human endeavor. However, behind the scenes, powerful computer-assisted translation (CAT) tools help translators improve their workflow.

So, what are CAT tools? And why do 8 out of 10 translators swear by them?

In this comprehensive guide, we'll explore what CAT software is, how they work, and how they can help you purr-fect your translation process.

Pro tip: Stop juggling multiple translation tools. To streamline your translation workflow, use Centus—a localization management platform with translation memory, term base, QA checks, and many more advanced CAT features.

What are CAT tools?

What are CAT Tools? Computer-assisted translation (CAT) tools are digital tools that increase the productivity of translators. CAT tools are used to enter, edit, store, and organize multilingual content. Typical CAT tools features include translation memories, termbases, terminology extraction, style guides, quality assurance, and reference management, among others.

CAT tools can be installed locally on a computer or hosted in the cloud, accessible via a web browser. Less common are mobile app versions of CAT tools for iOS and Android devices.

Machine translation vs CAT software

Machine translation (MT) tools automatically convert text from one language to another, without human involvement. CAT tools, on the other hand, simplify the translation process, without entirely automating it. Many businesses combine both, using MT for initial translation and CAT to improve its accuracy.

The table below further details the difference between machine translation and CAT tools:

Purpose MT provides a quick, rough translation CAT tools are used throughout the translation process to manage terminology, leverage previous translations, and conduct quality checks
Human involvement MT tools translate without human involvement CAT tools simplify the translation process while requiring human involvement
Accuracy The accuracy of MT varies widely. It often requires human editing to ensure quality and context-appropriate translation. CAT tools improve the accuracy of human translators by providing reference materials and consistency checks. The final accuracy largely depends on the skills of the translator.
Use cases MT is often used for translating large volumes of content quickly, where perfect accuracy is not required. For example, translating social media content or internal documents. CAT tools are used in professional translation where quality and consistency are crucial. For example, legal documents, technical manuals, or marketing materials.

To sum it up, machine translation focuses on speed and automation, whereas computer-aided translation focuses on helping human translators maintain translation quality and efficiency.

Translation management systems (TMS) vs CAT tools

Translation management systems (TMS) are complete toolkits for handling translations. They combine CAT tools and machine translation features, along with project management tools. In simple terms, while CAT tools help with translation, TMS allows managing the entire translation and localization process from start to finish.

Here's a simpler side-by-side comparison:

Functionality TMS incorporates CAT tools and MT tools. Additionally, they have project management features such as reporting, resource allocation, tracking, and billing. CAT tools focus on aiding the actual translation work. They offer features such as translation memory, terminology management, and quality assurance.
Target users TMS are designed for use by translation project managers, translation agencies, language service providers, and enterprises CAT tools are targeted at individual translators, whether they are freelancers or employed
Use cases TMS are commonly used for complex or multiple translation and localization projects, where organization and coordination are essential CAT tools are used in the everyday work of translators, helping them to translate more efficiently and consistently

Common CAT tool features

Just like how a calculator helps with complex math problems, CAT tools assist with translation tasks that would’ve taken much more time and resources. To this end, it makes use of several tools like translation memory, termbases, and quality assurance tools, amongst others.

  1. Translation memory (TM) is a database of previously translated sentences, phrases, and paragraphs. If the same or similar text appears again, the TM suggests the earlier translation. This way, translators don't have to translate the same text multiple times, saving time and ensuring consistency across all their work.
  2. Termbase or translation glossary is a custom translation repository for translators. It keeps a record of specific terms and their approved translations. It also provides context on how they are to be used. For example, technical terms or company-specific language. This guarantees the correct use of terms across all documents.
  3. Segmentation is a feature that breaks down the text into manageable parts, typically sentences or phrases. This makes it easier for translators to work on small sections at a time.
  4. Terminology extraction is a tool that automatically identifies and extracts key terms and phrases from the text. These terms are then added to the termbase or glossary for reference, and to ensure consistent translation throughout the project.
  5. Alignment compares previously translated texts (typically from a different document on a similar subject) with the new source text to identify matches and potential suggestions. This can save translators time by pre-populating existing translations and highlighting areas that need more attention.
  6. Reference management tool organizes and provides easy access to reference materials such as previous translations, glossaries, and style guides.
  7. Review tools help translators and editors review, proofread, and make corrections to translations for higher-quality translations.
  8. Style guides outline specific language or brand guidelines to ensure consistency in tone, terminology, and style across all translations. Some CAT tools also let you import your own style guides.
  9. Automated quality check is a feature that scans translated text for potential errors such as missing translations or inconsistent terminologies, helping to maintain a high level of quality and accuracy.
  10. Project management features help track and manage multiple translation projects. These can include monitoring deadlines, managing different resources, and tracking project progress.

How do CAT tools work?

CAT tools break down the source text into smaller, manageable segments. As the translator translates the segments, the tool saves them in a database, known as translation memory (TM). Over time, the tool can suggest translations for similar or identical segments, thereby simplifying the translation process. How do CAT tools work

Let’s break this down further:

  • Stage 1. Text importation: The process begins when a translator imports a text document in the source language into the CAT tool. This document could be in various formats, including Word, PDF, Excel, or HTML.
  • Stage 2. Text analysis: Once the document is imported, the tool performs an analysis. It identifies and separates only the translatable text. This text is further divided into smaller segments, usually sentences or phrases, to be translated individually. This process, known as segmentation, makes the text easier to manage.
  • Stage 3. Translation memory: Next, the CAT tool checks each segment against previously translated segments stored in the translation memory. If the same translation or similar match is found, the tool suggests that translation.
  • Stage 4. Translation: For segments without a TM match, the translator manually translates the text, and the CAT tool stores both the source text and its translation in the translation memory. In some cases, they may also use machine translation for a rough translation that the translator can refine further.
  • Stage 5. Terminology management: While translating, the CAT tool continuously checks against the stored terminology database. If a term from the database appears in the text, the tool can suggest the approved translation.
  • Stage 6. Quality assurance: After the translation is complete, the CAT tool can perform automated quality checks. It can spot potential errors such as missing translations, spelling mistakes, or inconsistent use of terminologies. This is the same as testing a localized app or website before launch.
  • Stage 7. Exportation: Once all translations are finished and checked, the text can be exported from the CAT tool back into its original format, maintaining all original formatting and layout.

What are the benefits of using CAT tools?

CAT tools simplify translation work by automating editing, formatting, and terminology management tasks. They ensure consistent and high-quality translations across various projects and adapt to different professional needs. With CAT tools, translators work more efficiently, saving time and money. Recognizing these benefits, freelance and in-house translators extensively use CAT tools.

Here are the main benefits of CAT tools:


A recent survey by ProZ shows that 93% of CAT tool users agree using a CAT tool helps them translate more efficiently. CAT tools, with their translation memory and glossary features, help translators avoid redundant work. For instance, if a translator comes across a segment they have translated before, the tool can auto-fill the translated text, saving time and effort.


Consistency in translation is important, especially in large projects or those that involve technical jargon. With terminology management, CAT tools ensure that the same terms are translated the same way across a project.

Quality control

With features such as spell-check, grammar-check, and consistency-check, CAT tools help translators maintain high-quality translations. They also provide an overview of the translation, helping to spot and correct errors that might otherwise go unnoticed.


CAT tools also help with easier collaboration between translators, editors, and proofreaders. They allow multiple people to work on a document at the same time, making team projects more streamlined.


CAT tools reduce costs by speeding up translation tasks and reducing repetition. With less time spent on each project, expenses go down. Translation memories also save costs by reducing the work needed for repetitive or updated translations. Better translations from the start mean fewer costly revisions later on.

How to choose the right CAT tool

Selecting the right CAT tool involves assessing its ease of use, necessary features like translation memory, language and format support, pricing, customer support, and integration with other software. This can seem daunting, given the multitude of options available on the internet today. But it is not impossible.

Here are the key factors to consider when selecting the best CAT tool for your needs:

  • Ease of use: The user interface should be intuitive and easy to navigate. CAT tools with steep learning curves can slow down your translation process instead of aiding it. If the tool’s UI is not user-friendly, then you might want to look at more accessible options.
  • Features: Identify the features you need most. This could include translation memory, terminology management, spell-check, or collaborative capabilities. Ensure the CAT tool you choose provides these features. Remember, you might not need all the costly bells and whistles.
  • Support for languages and formats: Make sure the CAT tool supports all the languages you work with. It should also handle the file formats you commonly encounter.
  • Integration: If you use other software in your work, such as a translation management system, check that the CAT tool integrates well with them.
  • Training and support: Good customer support is crucial. You want to know that help is available if you encounter any problems. Some companies also provide training on how to use their CAT tool effectively.
  • Price: Consider your budget. While some CAT tools are free, others require a subscription. Look for a cost/value balance.
  • Reviews and recommendations: Read reviews and ask other users for their experiences with different CAT tools. This firsthand feedback can provide valuable insights.

Remember, the best computer-assisted translation tool depends on your specific needs and translation workflow. Think about the kind of projects you usually handle, your technical comfort level, and your workflow/interface preferences.

The only CAT tool you’ll ever need

 Centus dashboard

CAT tools can make your translation work simpler and quicker. Yet, the real power comes when you manage them efficiently, and that's where Centus comes in.

Centus is an affordable and easy-to-use translation management system designed to help you manage and optimize your CAT tools. It doesn't matter if you're just starting with translation or handling complex projects; Centus scales with your needs. And with excellent customer support, you're never alone in your translation journey.

Why juggle multiple CAT tools when Centus has all the CAT, TM, and TMS features you will ever need? Try Centus now!

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