Teaching over a video call has one recurring problem: the moment you need to show something rather than say it, most tools get in the way. A slide deck is fixed, a chat box is tiny, and a document is not built for drawing a triangle and labelling its angles while a student watches. What online lessons actually need is a board you can share on screen, write on live, and let the class follow line by line — the way a real classroom board works. A full-screen online whiteboard does exactly that, right inside your browser, with no sign-up and nothing to install. This guide is written for teachers and tutors: how to share the board cleanly on Zoom, Meet or Teams, how to run a lesson on it, and how it keeps your students' work private and your session saved.
Why Full-Screen Matters for a Lesson
When you share your screen in a video call, your students see everything you see — including your tabs, your bookmarks bar, your taskbar, and any notification that pops in. For a lesson, that clutter is not just untidy; it is a distraction competing with the thing you are trying to teach. Full-screen mode removes all of it. Using the browser's built-in Fullscreen API, the canvas is promoted to fill the entire display, so what the class sees is a clean board edge to edge and nothing else.
That clean frame does more than look tidy. It gives every diagram the whole screen to breathe, so a student squinting at a shared window on a small laptop can actually read what you write. It keeps a private message or a browser alert from flashing in front of a class. And it makes the board behave like a purpose-built teaching surface rather than a website you happen to have open — which is exactly what you want when a room, or a Zoom grid of faces, is looking at your screen. Under the hood it is the same drawing engine as the general online whiteboard; full-screen simply frames it for an audience.
Sharing the Board on Zoom, Meet or Teams
The workflow is deliberately simple, because a lesson should not start with a fight against software. Open the full-screen board app in your browser — it loads straight onto a blank canvas with the pen already selected, no welcome screen and no account form. Then start screen sharing in your video call and choose to share that browser window or tab. In Zoom, Google Meet and Microsoft Teams the step is the same: hit "Share screen," pick the window, and your students see the board.
For the cleanest result, press the fullscreen button (or open the full-screen whiteboard tool page and go fullscreen there) before or just after you start sharing, so the class only ever sees the canvas. A common setup is to share the whole screen while the board is in fullscreen; another is to share just the browser tab, which keeps the rest of your desktop out of the call entirely. Either way, because the board is an ordinary web page you can bookmark it, pin it as a tab, and have it ready one click before every lesson. If you teach from a two-monitor setup, keep the board fullscreen on one screen and your video call and notes on the other.
Running a Lesson: Building an Idea Live
The reason a whiteboard beats slides for teaching is that students learn from watching something take shape, not from being handed the finished picture. On the board you can work a maths problem line by line, sketch a diagram a textbook only ever shows completed, or build up a mind map one branch at a time so the class follows your reasoning as it unfolds. The smooth vector pen keeps freehand writing crisp — important when it is being squeezed through a video call's compression and redrawn on a dozen different screens.
Because everything you draw is a real, editable object rather than a flat picture, you can teach the way you actually think. Move a box to make room, re-point an arrow when a student asks "wait, which one?", change a colour to highlight the step that matters, or reorder items to show cause and effect. Smart shape recognition turns a rough freehand rectangle or circle into a clean shape, so a hand-drawn diagram does not look messy on a shared screen. Sticky notes are handy for parking a question to return to; the highlighter is perfect for emphasising a key term without rewriting it. When you need space, mouse-wheel zoom and space-bar panning let you pull back to the whole problem or push in on one detail without ever leaving the canvas.
Annotating Over Ideas and Worksheets
A lot of tutoring is annotation: taking something that already exists and marking it up while you explain. You can paste or place an image on the board — a scan of a worksheet, a photo of a student's homework, a diagram — and then draw straight over it. Circle the mistake, underline the instruction the student skipped, draw an arrow from the question to the clue that answers it. Line styles (solid, dashed, dotted), arrowheads, and adjustable width, colour and opacity give you a full annotation kit, so your marks read clearly on top of whatever you are correcting.
Everything stays movable, so annotation is never destructive. If you mark up a diagram and then want to reset it, you select and remove the marks; the underlying image is untouched. That makes the same worksheet reusable across several students in a day without re-importing it each time.
Students Following Along
The point of a shared board is that the whole class is looking at the same thing at the same time. On a screen share, students see your board update in real time as you draw — there is no lag between your explanation and the visual, the way there can be when you talk over a static slide. Because full-screen gives the board the entire display, the writing is large enough to read on a phone joining the call, and the controls are big, touch-friendly targets that are comfortable if you are teaching from a tablet or an interactive display rather than a mouse.
Accessibility is built in for the students who need it. The board announces its active tool and important state changes to assistive technology through aria-live regions, so a student relying on a screen reader is not shut out of what is happening on the canvas. That matters in a real class, where you cannot assume every learner is watching the pixels.
Handing Out the Lesson Afterwards
A lesson taught on a board should not vanish when the call ends. When you finish, export the whole board and send it to your students as notes: a print-ready PDF or PNG, a lossless SVG, or a JSON scene file that reopens for editing next time. Students get the exact board they watched you build — the arrows, the corrections, the order you revealed things in — rather than a tidied-up reconstruction that hides the working. There is also a copy-to-clipboard option that drops a PNG straight into a chat or an email, which is often all a quick tutoring recap needs. For a fuller comparison of when to reach for each format, our guide on a free full-screen online whiteboard covers the presenting-and-exporting side in more depth.
Autosave: Your Lesson Is Never Lost
Between back-to-back lessons, the last thing you want is to lose a board because a tab closed or a call dropped. The whiteboard autosaves to your browser's local storage after every change, so if you close the tab, switch monitors, or your laptop sleeps, your work is still there. Reopen the board app and your last scene is restored exactly as you left it — the bookmarkable full-screen app is designed to reopen straight into your saved board. That makes it a reliable place to prepare a lesson in advance: set up the diagram before class, leave it, and it is waiting when the student arrives.
Private by Design: Nothing Is Uploaded
Teaching often means handling material you should not scatter across the internet — a student's name on a worksheet, a photo of their handwriting, a class's work. This board is built so that never happens. Everything you draw is created locally in your browser on the HTML canvas, and the board file itself is never uploaded, never stored on a server, and never tied to an account. Your students see your screen because you are sharing it in the call, but the underlying file stays on your machine. Privacy here is not a policy you have to take on trust; it is simply where the data lives. If the no-account angle is what you value most, our guide to a free online whiteboard with no sign-up goes deeper on that.
The Honest Limits for a Classroom
It is worth being clear about the trade-off. Because your board stays on your device and is never uploaded, there is no built-in live co-editing where every student draws on the same canvas from their own machine — that is inherently a server feature, since something in the middle has to relay everyone's strokes. For the common lesson shape, though, that is rarely what you need: you are teaching, the class is watching your shared screen, and the board is your surface to build on. When a student does need to contribute, they can draw on their own copy and export it to you, or take control of the share and use the same board. For solo and small-group teaching over a video call, a private, full-screen, no-sign-up board covers the job cleanly, and export closes the gap whenever you need to hand something over.
Open It and Teach Your Next Lesson On It
The fastest way to see whether this fits your teaching is to open it before your next session. Launch the full-screen board app, share your screen in Zoom, Meet or Teams, and start writing on a clean edge-to-edge canvas — or open the full-screen whiteboard tool page for the full toolkit and go fullscreen from there. It runs in your browser, autosaves every lesson locally, works on any device, and never uploads a thing: a real board for online teaching, ready the moment class starts.