The hard part of a timed online test is not knowing the material, it is recalling it fast enough while the clock runs. The fix is not a tool you lean on during the test, it is the practice you put in before it. Lensia is a Chrome extension built for that prep, and the piece you will use most is the sidebar chat: a panel that opens next to your practice material and stays there while you drill. You run a timed set, then work through every question you missed in the same chat until the reasoning is automatic. By test day the recall is yours. Install Lensia free and start prepping for your next timed online test today.
Read this first. Lensia is a study aid for preparing before the test. Use it on practice sets, past questions, and your own review, and to check your work after you attempt it. Using any AI during a graded, AI-restricted test is academic dishonesty, and this guide is about the opposite: getting fast enough that you do not need help when it counts. It also cannot run inside a locked-down exam browser like Respondus LockDown Browser, which disables Chrome extensions entirely.
Why timed tests reward drilling, not cramming
A timed test measures two things at once: whether you know the concept, and whether you can reach it under pressure. Cramming the night before loads the first and ignores the second. You have felt the result, staring at a question you *know* you studied while the timer eats your margin.
Drilling fixes the recall gap. You practice under something like real conditions, get the reasoning wrong a few times where it is cheap, and build the speed that only comes from reps. The sidebar chat is what makes that loop fast, because your practice and the explanation live side by side.
The sidebar chat: your prep workspace
Open the sidebar from your Chrome toolbar. Chrome's side panel opens next to your material, and it is on every plan.
It runs the whole drill loop in one place because it holds a conversation, not a single answer:
- Conversation history stays between sessions, so a week of practice threads is still there to review the night before.
- Bookmarks save the explanations for the concepts you keep missing, so your weak spots are one click away.
- A model picker lets you start quick recall drills on a fast model and switch to a stronger one mid-thread when a tricky derivation needs care.
Here is the loop in practice. Set a timer, work a practice set cold, and stop when it rings. Then paste each missed question into the sidebar, read why your answer fell apart, and ask "give me two more like this" to drill the same idea until it is fast. That is how you turn a shaky topic into an automatic one. For the study habits that make this stick, read the study smarter guide.
What paid tiers add
The sidebar is free. For heavier prep, Basic adds about ten times the usage, the reasoning toggle (a single on/off switch that tells the AI to slow down and check multi-step work), custom instructions, web search and fetch URL, and the Advanced models. Pro has the highest usage budget and adds agent mode in the sidebar, which can read your open notes, take a fresh screenshot, and chain steps before it answers.
The floating panel: check one question fast
Not every review needs a full chat. When you are reading back over a practice set and one answer stops you, the floating panel is faster. Press Ctrl+Shift+X, drag a box around the question, and a worked explanation floats up on top of the page in about three seconds, without pulling you out of what you are reading. It is on every plan.
Two things keep the panel useful, not just a one-off:
- Ask Mode turns the panel into a custom-question box. Type your own prompt and attach up to three images, so you can compare two practice diagrams or ask something a single screenshot cannot hold.
- Quick Capture (
Ctrl+Shift+F) repeats your last capture area without redrawing the box, which is ideal for stepping through a page of practice questions laid out the same way.
Press Ctrl+Shift+E to hide the panel and bring it back with the same keys. For how both surfaces fit together, read how Lensia works.
Build a timed-test prep routine
- Simulate the clock. Practice with a timer set to the real per-question pace, so speed is part of what you train.
- Grade it honestly. Mark what you missed and, more importantly, what you got right but slowly.
- Work the misses in the sidebar. Ask why each one fell apart, then ask for two similar questions and redo them.
- Drill the slow ones too. A right-but-slow answer is a wrong answer on a tight timer. Ask the sidebar to generate a focused set on that concept.
- Re-test cold the next day. If you can reproduce the reasoning without help, it is yours.
For multiple-choice-heavy tests, put every answer option into the sidebar so it can explain why the right one holds and the others fail. That reasoning is what transfers to the reworded version on the real exam. More on that in AI for multiple-choice practice.
Which plan fits your prep
Leave the model on Lensia Max and it picks a fitting Quick or Standard model per question and takes 15 percent off the cost, which adds up over a long drill session. Free covers a real prep session with the sidebar, the floating panel, Ask Mode, and Lensia Max. Basic and Pro add reasoning, the Advanced models, and more usage for a full exam season. Sign in with Google to activate. For a wider view of study tools, read the AI homework helper complete guide.
Get ready for your next test
Setup takes under two minutes. Install Lensia from the Chrome Web Store, sign in with Google, and open the sidebar next to your first practice set. Drill it, work your misses, and get fast enough that the clock stops being the thing you are afraid of.