Homework is piling up, the textbook explanation is not clicking, and something is due. The smart way to use AI for homework is not to paste a question into a random chat tab and copy whatever comes back. It is to keep an AI open beside your work and actually talk through the problem. That is what Lensia does. It is a Chrome extension whose main surface is a sidebar chat: a panel that opens next to your assignment and stays there while you work, so you can ask, read, push back, and ask again until the method makes sense. Get Lensia free and have it running in about a minute.
Lensia is a study aid. Use it to learn how a problem is solved, to build your own practice, and to check your work after you have tried it yourself. Using it during a graded assessment where AI is restricted is academic dishonesty, and that is not what this guide is about.
Start with the sidebar chat
Open the sidebar from your Chrome toolbar. Chrome's side panel opens next to your assignment, so your work and the chat stay side by side. It is on every plan.
The reason the sidebar is the main way to use AI for homework is that homework questions rarely resolve in one message. You need the follow-up. Paste a problem, read the walkthrough, then type "why does step two work?" and keep going. Along the way it holds a real conversation:
- Conversation history stays between sessions, so the thread from Monday's problem set is still there on Thursday.
- Bookmarks save the explanations you will want again before a test.
- A model picker at the top lets you start a quick question on a fast model, then switch to a stronger one like Claude Sonnet 5 mid-thread when a problem gets heavy.
A good loop looks like this: attempt the problem yourself, paste your attempt into the sidebar, ask where it went wrong, then redo it from scratch without looking. For the study habits that make this pay off, read the study smarter guide, and for the full tour of both surfaces, how Lensia works.
What paid tiers add to the sidebar
The sidebar is free. On Basic and up it can run a web search or fetch a URL you give it, so it pulls a formula or source into the explanation instead of guessing. On Pro, agent mode lets it chain steps inside the sidebar: read the notes open in your tab, take a fresh screenshot, look something up, then walk you through the result.
The floating panel: grab a question off the page
Not every question needs a conversation. Sometimes you are reading and one line stops you, and you just want it explained without leaving the page. Press Ctrl+Shift+X, drag a box around the problem, and a step-by-step explanation floats up on top of your work in a few seconds. It runs on every plan.
The panel is more than a one-shot tool:
- Ask Mode is a switch that turns the panel into a custom-question box. Type your own prompt and attach up to three images from your screen, which is handy when one screenshot cannot hold the whole question or you want to compare two figures.
- Quick Capture (
Ctrl+Shift+F) repeats the last capture area without redrawing the box, so a worksheet of ten similar problems takes one keypress each. - Ctrl+Shift+E hides the panel completely and brings it back with the same keys.
Which subjects it handles
Both surfaces read whatever is on your screen, so they work on anything in a browser tab.
- Math and STEM: attempt it, then paste or capture the full problem with its numbers, graphs, and units. Turn on reasoning mode for multi-step derivations and compare the worked steps against yours. The math homework guide goes deeper.
- Science short answer and labs: drop a data table in with the question so the AI can explain how the data leads to the answer.
- History and reading: paste a passage into the sidebar and ask for an outline or thesis structure to study before you write your own.
- Multiple choice practice: works across Canvas, Moodle, Blackboard, Schoology, Top Hat, Google Forms, Pearson MyLab, and McGraw-Hill Connect. Use it on practice and review to learn why an answer is right, not to fill in a graded item.
- Vocabulary: a quick capture or a short sidebar question returns a clear definition in seconds.
Custom instructions
If you use Lensia across several classes, Custom Instructions save an explanation style once, like "explain like I'm in high school" or "always show the calculation," and the AI applies it on every capture and every chat without you retyping it.
Build speed before the test
The best time to use AI is before an assessment, not during one. Turn a study session into a rehearsal:
- Ask the sidebar to generate fresh practice problems on a topic, then solve them yourself.
- Capture a problem you already attempted and ask the AI to check your work and point to the exact step that went wrong.
- Time yourself so the real test feels familiar.
For a platform-specific version of this, read studying with AI on Canvas.
Models, reasoning, and Lensia Max
Both surfaces share the same models and budget:
- Quick models: GPT-5.4 Nano, Gemini 3.1 Flash Lite, DeepSeek V4 Flash, GPT-OSS 120B, Qwen3.5 Flash. Fast, good for definitions and easy recall.
- Standard models: GPT-5.4 Mini, Gemini 3 Flash, Claude Haiku 4.5, Grok 4.3, DeepSeek V4 Pro. A good balance of speed and depth.
- Advanced models (Basic and up): GPT-5.4, GPT-5.5, Gemini 3.1 Pro, Gemini 3.5 Flash, Claude Sonnet 5, Claude Opus 4.8. The clearest walkthroughs for hard multi-step problems.
Reasoning is a single on/off toggle; flip it on when a problem needs careful multi-step thinking. Leave the model on Lensia Max and it picks a fitting Quick or Standard model per question and takes 15 percent off the cost.
Choosing a tier
Every tier includes the sidebar chat and the capture panel, and every tier signs in with Google. Sign in once to activate.
- Free covers Quick and Standard models, Ask Mode, and a starter study budget. Good for the occasional homework question.
- Basic adds about ten times the usage plus the Advanced models, reasoning, web search, fetch URL, and custom instructions.
- Pro adds the highest budget, agent mode in the sidebar, and Auto-Solve on Vocabulary.com.
Start free and upgrade when you hit the limit. The complete AI homework helper guide covers every feature in detail.
Start studying smarter now
Open your assignment in Chrome, open the sidebar, and paste in the first thing you are stuck on. Then use Ctrl+Shift+X on the next problem you want explained fast. Install Lensia free; setup takes under two minutes.