Best Free IB Biology Websites (2025)

Having gone through the IB myself, I believe Bioninja is the best free IB Biology websites in 2025. During years in the IB, I used Bioninja not only for studying but also revising before every exam/test.

What makes Bioninja special is that it is created by real IB bio teachers who thoroughly know the syllabus inside and out. Compared to other, more general biology websites that over/under simplify content, omit details which you are required to know, or even get information wrong (at least, according to the IB syllabus, that is), Bioninja runs parallel to what is actually assessed. Why is this important? By aligning with the IB syllabus, it means you waste less time on irrelevant information, something of which I often fell victim to, and more on what is actually useful.

As per the structure, Bioninja is very well structured, having all the information organised into their respective topics, themes and units. Additionally, with good visual elements, and a clear distinction between HL and SL content, it makes the website easy to navigate, especially when you are revising for a specific topic. Combined with the the well written information thats, not too long or convoluted, the structure is definitely one of its strong suites.

Moving onto the content and the resources provided, Bioninja offers everything from downloadable PDFs, concise summaries, interactive diagrams, worksheets, and even PowerPoint slides. This means, whether you want to revise or relearn e.g. before the final exams, Bioninja has something for you.

Finally, as of writing this (Aug, 2025), the website has been updated to fit the newly introduced syllabus, something that not many resources have been able to do. That said, it should be mentioned that, with the syllabus being new, and same with the updated website, bioninja does not have all of the HL content yet :(

All in All, I would Strongly recommend using Bioninja for everything (from studying to revising) as it simply works and provides you with all the resouces you need.

While I never personally used Biology for Life during my time in the IB, my sister did, and she spoke very highly of it. From what I’ve seen, it’s a straightforward, free IB Biology resource with reliable and syllabus-focused content. That said, I’m not entirely sure if all of the material has been updated to match the most recent syllabus, so it’s worth double-checking topics with a newer site like BioNinja or StudyIB just to be safe.

The site is well-organised by syllabus topic, with clear explanations, diagrams, and downloadable resources that make it easy to find exactly what you need. It also includes sections on IB-specific skills like data analysis, lab work, and the IA things that are often overlooked by other sites.

Overall, based on my sister’s experience and my own review of the site, I’d say Biology for Life is a strong, trustworthy option. Just keep in mind the possible syllabus update gap, and you’ll get plenty of value from what it offers.

Where do I begin? StudyIB is a legendary website that has carried me throughout my time in the IB system. From first learning about the site in my psychology class (I will never forget you John Crane), to using it in economics, StudyIB has it all; however this is about bio so...

Usually StudyIB requires a payed login to access all of the resources, and it does; however the IB biology section has free introductory sections ( there is also a payed version with everything which is about $65 USD annually which I strongly recommend), even without an acount. A major strength of this website is how concise the information is. Similarly to Bioninja, the content is created by real IB biology teachers meaning it is curated to the IB. This is massive advantage when it comes to revising efficiently as it allows you to focus on the content without worrying that you are studying something that wont even be on the exam. Additionally, Be it in SL or HL, the website offers structured information on each topic, and is nicely organised.

Another strength is its vast array of tools which you can use to revise. For each topic (almost each topic), you have access to topic notes, flashcards, videos, quizzes and interactive mini "lessons" which are very helpful, as well as these small "skill" boxes. Essentially, each "skill box" has a few questions or some information which allow you to test yourself to see if you know everything you should know from the page. I have personally found this very helpful.

Overall, StudyIB is a good website that is reliable, and provides good information. Just keep in mind that not everything is available for free.

IB Guides is a bit of an everything website as it essentially has information on all of the base IB courses. This means, while it does have information on biology, and all of its respective units, it is rather concise and sometimes can lack details for HL students.

Also. it should be noted that, IB Guides is actually very old. Certain information was originally prepared for earlier syllabases (e.g. Biology 2009), and the site in general has not been very thoroughly revised in several years. That saud, IB Guide is strong in terms of structure and accessibility. Every topic is separated by syllabus topic meaning the website is easy to navigate.

That is about all I have to say, however if I could give one tip, use the website to review topics you already know, not for learning them. ALternativly, you can use it to guide your studying by seeing what topics you need to know.

So, to conclude, IB Guides is a convenient, well-organised website, but is very dated. It is useful as an initial pointer or general guide, but for current exam preparation, I strongly recommend more recent sites such as BioNinja or StudyIB (this is not to say that should not use the website to study for your exams, just use it as a supplement).

i-Biology, another website I didnt really use personally. Before you jump in, it’s worth knowing: the site is quite old as well meaning most of the links do not work anymore.

Each topic or unit, and sub-topic have a slideshow that you can go through. This is what I recommend you focus on when using this website as, like mentioned, it is a very old website. Also, if you’re working on your IA, Paper 3, or even your EE, some of the resources here can give you ideas and examples.

As per the structure, it is decent, with content split into topics and themes, however the UI and UX is not the greatest as you will see. Personally, I’d say use i-Biology when you have already studied amd just want to revises a little bit.

All in all, i-Biology is still a valuable IB Bio resource if you use it wisely.

At this point I am guessing we all already know Khan Academy so I will just keep it short. The videos and lessons he has are very good in general, with good information and detail. Additionally, the formatting of the lessons is a little different to some of the other websites meaning it can be a nice change of pace, especially during long study hours.

One thing I will say is that, the information is not detailed enough for HL bio so just keep that in mind. The way I used Khan Academy was more for revision. As you watch the videos and do the "tests", test yourself to see if you can recognise what information is missing and what not.

DISCLAIMER: Anki does require you to dowload it, however it is free and is rather simply to instal.

Anki is not really a website if I am going to be honest, however I really think that not enough people have realised the value in them so I just added them anyway. In this (not) website, there is a collection of flashcards made by other people, some for IB bio and others for bio in general. This means. the quality, correctness and syllabus allignment varies depending on which flashcard you decide to get. Personally, I have found them very useful for revision and active recall as you can get the app on your phone (not free, sorry) and study/revise during your commute. My commute was a little over an hour soooo.....

The main strength of this website is that it saves you time from making your own flashcards, and with navigating the website being easy, I strongly recommend you just take a look and see if you can find any flashcards you might want to use.

Some of you may have already seen some of their animations, however did you know they had a website? Sumanasinc is a good website that has a host of animations showing the different processes like miosis, the "Life Cycle of a Moss" and more. Being a visual learner myself I found these animations very helpful. The website is easy to navigate as it is essentially only one page (for biology), so there is not much else to say, other than I would recommend taking a quick looksi.

Again, I am going to be honest I never really used this website during my IB time, however that does not mean you should't. Bozeman Science is an educational video channel (It can also be found under the channels tab!) created by Paul Andersen, a former high school science teacher, and it’s a good resource for late studying. While it’s not IB-specific, it is great for filling in gaps or reinforcing difficult concepts. The guy is good at explaining stuff, like cellular respiration or the Calvin cycle in a way that’s clear, logical, and he often uses simple, hand-drawn visuals. The videos are well-paced, and his calmness makes them especially helpful when you are getting a little tired.

That said, because Bozeman Science is designed for a broad audience, the content doesn’t always match the IB syllabus point-for-point. Sometimes he’ll cover more/less detail than you need. Also, the production style is straightforward, not flashy, but the explanations are zupa.

Overall, Bozeman Science is one of the best general biology video resources out there. I’d say it’s ideal as a supplementary learning tool rather than your primary revision website.