When you hit a practice problem and have no idea where to start, the usual move is to open a new tab, paste the question into a chat tool, skim a paragraph you only half understand, and move on. You get an answer but no grasp of *how* to reach it, which is exactly what trips you up on the real test. A good AI study helper works the other way. Lensia is a Chrome extension whose main surface is a sidebar chat that opens next to your study page and stays there: you ask a question, read the explanation, ask a follow-up, and keep going until the concept actually lands. When something on the screen stops you mid-read, a floating panel grabs it in a couple of seconds without breaking your flow. Either way you learn the method, not just the letter. Install Lensia free.
One honest note up front: Lensia is a study aid. Use it on practice problems, your notes, review material, and to check your own work *after* you attempt it. Using it during a graded assessment where AI is restricted is academic dishonesty. This guide is about the legitimate use: understanding concepts and preparing before the test.
The sidebar chat is where you actually study
An AI study helper is only useful if it explains, and explaining usually takes more than one message. That is why the sidebar is the surface you will live in. Open it from the Lensia icon in your Chrome toolbar, and a chat docks in Chrome's side panel next to your material. It is on every plan.
Because it holds the whole conversation, the sidebar is built for working a topic out:
- Conversation history stays between sessions, so last week's genetics thread is still there when the exam looms.
- Bookmarks save the explanations you know you will reread, instead of scrolling to find them.
- A model picker lets you start a quick recall question on a fast model, then switch to a stronger one mid-thread when a proof needs real care.
Paste a problem, read the walkthrough, then type "why does step two work?" and press again. That loop is the difference between an answer and understanding. For the surface-by-surface breakdown, read how Lensia works.
The floating panel: grab a question off the page
Not every question deserves a full chat. Sometimes you are reading and one line stops you. Press Ctrl+Shift+X, drag a box around it, and a worked explanation floats up on top of the page in about three seconds. The page stays visible underneath and the panel is draggable, so you can park it beside the problem.
Two shortcuts make it faster. Ctrl+Shift+F repeats your last capture area without redrawing the box, which turns a page of similar practice items into one keypress each. Ctrl+Shift+E hides the panel entirely and brings it back.
There is also an Ask Mode switch on the panel, on every plan including Free. Flip it and the capture flow becomes a typing flow: write your own question, attach up to three images if one screenshot will not carry the whole thing, and send. Use it when you want the AI to read your exact wording, or to compare two images side by side.
A study habit that works on both surfaces
The tool is only half of it. The habit is the rest:
- Attempt the problem yourself first. That is where the learning happens.
- Stuck or unsure? Open the sidebar and ask, or capture the question with the panel.
- Read the explanation and compare it against your own attempt. Find the exact step where you went sideways.
- Close it, then redo the problem from scratch without looking. If you can reproduce the steps, you have learned it.
For multiple choice, include every answer choice so the AI can explain why one holds up and the others fall apart. For math, include the numbers, formulas, and conditions so it can show each step. A stronger move: ask the sidebar to generate extra practice on a topic from your notes, then attempt those cold. More on that in the study smarter guide.
Study on any site you already use
Both surfaces read from your screen, so nothing needs a special connection to your school's site. Work through review material, lecture slides, and practice content on Canvas (Canvas study guide), Moodle, Blackboard, Top Hat, Schoology, Google Forms practice sets, study sites, or a PDF open in the browser. If you can see it, Lensia can explain it. For platform-specific advice, read Canvas, Moodle and Blackboard tips every student should know.
What each plan unlocks
Every tier signs in with Google. Sign in once to activate and you are in.
Free covers the starter usage allowance, the sidebar chat with history and bookmarks, the floating panel with Ask Mode, Quick and Standard models, and the Lensia Max auto-router (it picks a fitting model per question and takes 15 percent off the cost).
Basic adds about 10x the usage, the reasoning toggle (a single on/off switch that tells the AI to slow down and check its work), custom instructions, web search and fetch URL inside the sidebar, and the Advanced models: GPT-5.4, GPT-5.5, Gemini 3.1 Pro, Gemini 3.5 Flash, Claude Sonnet 5, Claude Opus 4.8.
Pro adds the highest usage allowance, agent mode in the sidebar (it can read your open tabs, take a fresh screenshot, and chain steps before answering), and Auto-Solve Mode, which currently works on Vocabulary.com only for word-list practice. Every other platform uses the manual capture flow.
To build a full routine around all of this, read the AI homework helper complete guide.
Get started today
Setup takes under two minutes. Install Lensia from the Chrome Web Store, sign in with Google, open the sidebar on a problem you are stuck on, and reach for the floating panel on the next question you hit while reading. Understand the method, check your own work, and walk into the test prepared.