See how it will look before you connect.

The app’s settings screen draws your device with the settings you picked applied to it. This is that drawing, running in your browser. Change the orientation, the display mode or the resolution and watch both the PC and the tablet follow. Drag the window on the PC across onto the tablet.

Open the demo Close the demo

Drag the window to move it (or select the picture and use the arrow keys; Shift moves further). The 1 and 2 at the bottom left are the displays as Windows arranges them.

Device

The app reads the outline, corner radius and camera cut-out from the device itself.

Tablet Phone 4:3 tablet

Orientation while streaming

Applies only while streaming. Auto follows the device.

Landscape Portrait Auto

Display mode

Extend adds a new monitor. Mirror shows the screen you already have.

Extend Adds a second monitor to Windows. Mirror Shows a screen the host already has.

Virtual display resolution

The size of the monitor created on Windows. Matching this device avoids any scaling.

Refresh rate

How many hertz the monitor created on Windows runs at. It affects how smooth the pointer and scrolling feel.

Default Custom

Frame rate

How many frames are sent per second. It affects data usage and how warm the device gets.

Default Custom

Three typical device shapes stand in for yours. The PC screen is an example at 2560×1440. How many frames actually arrive depends on how often Windows composes the screen — see “What it does not do — yet” below.

Every line on this page is something we measured.

Second-monitor apps are easy to demo and hard to live with. So instead of adjectives, here is what came out of the test rig — and below, exactly how it was measured.

0steps

After a PC restart

Set up nothing

The installer adds the display driver, the firewall rule and the start-up entry itself. After a reboot the PC is already listening — open the app on the tablet and the screen is there. No “Windows Defender Firewall has blocked this app”, no port forwarding, no account.

12/12

Sessions recovered

It doesn’t break

Wi-Fi cut for 2, 5 and 10 seconds, four times each: every session came back on its own, onto the same virtual display. A tablet that leaves for good is cleaned up in 20.5 s, so you are never left dragging windows around a monitor that isn’t there.

7.999703

hdrSdrRatio on a Pixel 9

It does HDR

Measured on a Pixel 9: BT.2020 with a PQ transfer curve, end to end, with no silent fall back to SDR. HDR content on the PC arrives as HDR content on the tablet. HDR is part of Pro.

How this was measured. Host: Intel Core i7-11700, NVIDIA RTX 3060 + Intel UHD 750, Windows 11 (10.0 build 26200), gigabit Ethernet. Tablet: Lenovo Idea Tab Pro (Android 16), 1840×2944, Wi-Fi 6 at −46 dBm, same layer-2 network. Figures come from outside the product — NIC byte counters, GPU engine utilisation, and SurfaceFlinger frame timings on the tablet — not from the app’s own reporting. Bandwidth was measured on 1 September 2026, before transport encryption was added; a later run put the increase from encryption at roughly 2%. In the same test, on the same content, spacedesk used 24.7 Mbps. HDR was verified on a Pixel 9. Your numbers will differ with your resolution, your content and your network.

How it works

Three steps, once.

1 / 3
Install it on the PC

One installer. It sets up a virtual display driver, so Windows sees a genuine extra monitor with its own resolution — not a mirrored window you have to arrange around.
2 / 3
Open the app on the tablet

It finds the PC on your network by itself. If you would rather be explicit, scan the QR code the PC shows, or type the address once.
3 / 3
Leave it alone

Drag windows onto it, draw on it, walk out of Wi-Fi range and come back. Restart the PC and it is waiting again without being asked.

What else it does

Pen: Pressure, tilt and rotation arrive on the PC as real Windows pen input, so pressure-sensitive apps see a pen and not a mouse.
Webcam Pro: The tablet’s camera shows up on the PC as “PrismDesk Camera”, so you can pick it in Discord, Teams or OBS.
Four at once Pro: Four devices can connect to one PC, sharing a single capture and a single encoder. Four is the number we verified, so four is the number we publish.
Encrypted: TLS 1.3 on the control and input channels; AES-256-GCM on video, audio and camera. The tablet pins the PC’s certificate fingerprint.
Nothing leaves your network: No account, no telemetry, and no automatic update check — pixels go straight from your PC to your tablet, and nothing is collected about you. PrismDesk reaches the internet only while you are pressing a button: Activate (our payment provider) or Check for updates (one small file, no version and nothing about your PC). Leave both alone and it never leaves your network.
Quiet when idle: A still screen costs 8.9 kbps. Leaving a tablet propped up beside the monitor all day is not a bandwidth decision.

Price

The free edition needs no account and no card, and has no time limit to run out. Pro adds four things, once, for US$22.

Free

US$0

No account, no card, no time limit.

One device at a time
SDR picture
Pen and touch input
Audio from the PC

Download for Windows

Pro

US$22

One-time purchase. No subscription, no account.

Everything in Free, and:

HDRHDR10 to a device whose display and decoder support it.
Up to four devices at onceOne capture and one encoder, shared between them.
Device camera as a webcamShows up on the PC as “PrismDesk Camera”.
Input device modeThe device as a pen tablet with shortcut keys, for a screen your PC already has.

Pro is sold by Polar Software, Inc. as merchant of record, and one key covers three of your own Windows PCs. If it does not work on a PC that meets the requirements and we cannot fix it with you, you get your money back within 14 days — see refunds.

What it does not do — yet

Read this before you install. A second monitor that disappoints you on day two is worse than one you never installed. These are the things we would want to know first.

Windows 11 only — 64-bit, build 22000 or later. Windows 10 is not supported, and we have not tested it, so we do not claim it.
Same network only. Your PC and tablet share a LAN. PrismDesk is not a way to reach your desktop from a café.
We do not advertise a frame rate. The rate follows what Windows composes: on a 75 Hz primary display the achievable rates are 75, 37.5 and 25 — 60 is simply not on that list. Anyone promising you a number is promising you their monitor, not yours.
Long-run stability is not measured. We have not yet published a multi-hour soak test, so we will not tell you it is rock solid overnight.
Five Android devices tested — Pixel 3, Pixel 6, Pixel 9, Lenovo Idea Tab Pro and TCL Tab 11 Gen2. The TCL is the only budget device, and on it we checked only that it connects and shows the screen. Try the free edition on your own tablet before you pay for anything.

Requirements. Windows 11 64-bit (build 22000 or later) with administrator rights, and a GPU that can encode H.264 in hardware — NVIDIA NVENC, or an Intel or AMD encoder through Media Foundation. Android 8.0 (API 26) or later with a hardware H.264 decoder. Both devices on the same LAN, wired or Wi-Fi.

Help

Setting up, what to do when something does not work, and how each feature behaves. In Troubleshooting you can type the message you see and jump to the fix.

Get started

When something goes wrong

Features

Not there? Report a problem on GitHub or write to [email protected].

Try it on your own tablet.

The free edition needs no account and no card. Whether it works on your PC and your tablet is the only test that matters, so that is where to start.

1 · On your PC