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Welcome to Gamepad Tester — Key Rollover Test
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Key Rollover Test — Free Online Keyboard NKRO & Anti-Ghosting Tester

Free Online Key Rollover Test: Check Keyboard NKRO, Anti-Ghosting, Simultaneous Key Detection, Ghost Key Detection & Rollover Grade — 2KRO vs 6KRO vs Full NKRO — Instant, No Download Required

The most complete free online key rollover test. Find your exact keyboard rollover limit — 2KRO, 6KRO, 10KRO, or full N-Key Rollover (NKRO). Detect key ghosting and key blocking in real time. Test gaming combos like WASD plus Shift plus Space plus Ctrl. Check anti-ghosting coverage with preset gaming, typing, and shortcut key combinations. Works on all keyboards — mechanical, membrane, gaming, and laptop. No download, no install, no sign-up required.

NKRO Test Ghost Key Detect Live Key Counter 2KRO / 6KRO Check Gaming Combos Anti-Ghosting All Keyboards Mechanical / Membrane
Live Key Rollover Test
Press keys to test...
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Keys Now
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Peak NKRO
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Grade
Hold multiple keys at once — watch simultaneous count rise
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Keys Held Now
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Peak Simultaneous
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Rollover Grade
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Total Keys Pressed
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Ghosts Detected
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Unique Keys Tested
Live Key Rollover Test Tool
Key Rollover Test — NKRO, Anti-Ghosting & Gaming Combo Check
Click test area below and hold keys
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Hold multiple keys simultaneously — your rollover number will appear here
Click inside the test area below, then press and hold as many keys as you can at the same time. The counter shows how many keys are being registered simultaneously right now.
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NKRO Progress Meter
024681012+
Keys Held Right Now
No keys pressed — click the test area then hold keys
Click Below to Start — Press and Hold Keys
Click here to focus, then hold as many keys as possible simultaneously
⚠ Key Ghosting or Blocking Detected! Your keyboard is not registering all held keys correctly. The number of simultaneously registered keys dropped below your recent peak while you were still holding the same keys. This is a rollover limit or ghosting failure. Your keyboard's N-Key Rollover is approximately equal to your peak simultaneous count.
Hold down W + A + S + D then add Shift, Ctrl, Space, and more. A 6KRO keyboard will stop registering new keys after 6. A full NKRO keyboard registers every key you hold. The peak count shown is your keyboard's detected rollover limit. Note: Browsers may block some system keys like PrintScreen, Windows/Super, and some F-key combinations.
Gaming Combo Test — Press each combo and see how many keys register
Each card shows a common gaming or productivity key combination. Press those keys simultaneously in the rollover test area (first tab) and return here to see your results. Cards turn green if all keys were detected, red if any were missed.
WASD Movement
W + A + S + D
Not Tested
4-key diagonal movement combo used in virtually all PC games. Any keyboard should handle this — if one key is missing, check your keyboard matrix.
FPS Sprint Jump
W + Shift + Space + Ctrl
Not Tested
Forward sprint while crouching and jumping — common in Apex Legends, Fortnite, and Warzone. Requires 4-key simultaneous registration minimum.
Full FPS Combo
W + A + Shift + Space + Ctrl + E
Not Tested
6-key combo common in competitive FPS games — diagonal sprint jump while interacting. Tests the 6KRO limit of standard gaming keyboards.
MMO Ability Combo
1 + 2 + 3 + Shift + Ctrl
Not Tested
Number row abilities plus modifiers — used in WoW, FFXIV, and similar MMOs. Tests keyboard matrix coverage across number row and modifier keys.
Editor Shortcuts
Ctrl + Shift + Alt + Z
Not Tested
Triple-modifier shortcut used in code editors and creative software. Tests whether all three modifier keys register together with an action key.
Rhythm Game Chord
D + F + J + K + Space
Not Tested
5-key chord pattern used in osu!, StepMania, and other rhythm games. Many budget keyboards ghost on this combination due to matrix layout.
Fast Typist Roll
A + S + D + F + G + H
Not Tested
Home row simultaneous hold — tests the most commonly typed keys together. Should pass on any keyboard claiming 6KRO or higher.
NKRO Stress Test
Q+W+E+R+A+S+D+F+Space
Not Tested
9-key simultaneous press — a true NKRO keyboard registers all 9. Any key dropped indicates the rollover limit has been reached. Only full NKRO boards pass.
Arrow + Modifier
↑ + ↓ + ← + → + Shift
Not Tested
All arrow keys plus Shift — used in text selection and some fighting game inputs. Tests the arrow key cluster matrix independently of the main keyboard area.
To test each combo: go to the Rollover Test tab, click the test area, hold the specified keys, then switch back here. The combo card will update automatically when those keys are detected as held simultaneously. Green means all required keys registered — your keyboard handles that combination cleanly.
Key Rollover Types — Understanding 2KRO vs 6KRO vs NKRO
Type
Max Keys
Description & Use Case
Rating
2KRO
2 keys
Cheap membrane keyboards and basic USB HID boot protocol. Cannot handle gaming or fast typing. Pressing three keys causes ghosting or blocking. Common on budget office and laptop keyboards.
Poor
3KRO
3 keys
Slightly better budget keyboards. Can handle simple combos like Ctrl+Alt+Delete. Still fails on gaming movement combos that require 4+ simultaneous keys.
Poor
6KRO
6 keys
Standard for most gaming keyboards and quality USB keyboards. Handles the vast majority of gaming combos. The USB HID standard specifies 6 simultaneous non-modifier keycodes. Most "gaming" keyboards without explicit NKRO advertising are 6KRO.
Adequate
10KRO
10 keys
Enhanced gaming keyboards with improved matrix design. Covers all practical gaming use cases. Found in mid-range mechanical gaming keyboards. Modifiers (Shift, Ctrl, Alt) typically add on top of the base count.
Good
NKRO
Unlimited
Full N-Key Rollover — every key is registered individually regardless of how many are held simultaneously. Required for competitive gaming, rhythm games, music production MIDI input, and professional data entry. Standard on quality mechanical keyboards. PS/2 natively supports NKRO. USB NKRO requires specific firmware.
Best
Modifier key note: Shift, Ctrl, Alt, and Windows/Super keys are handled separately by most keyboards and do not count toward the rollover limit. A 6KRO keyboard means 6 regular keys plus any modifiers simultaneously. This is why a 6KRO keyboard still handles combos like Ctrl+Shift+Alt+Z — modifiers are free. The rollover limit only applies to non-modifier keycodes.
Key Press History — Last Simultaneous Combinations Recorded
No key combinations recorded yet — press multiple keys simultaneously in the Rollover Test tab
Key Event Log
——Click the test area and press keys to begin logging...
What the Key Rollover Test Checks

Simultaneous Key Count

Counts exactly how many keys your keyboard registers at the same moment. The live counter updates every frame as you hold and release keys. Your peak simultaneous count is your keyboard's effective N-Key Rollover number — the true limit before ghosting or blocking occurs.

Ghost Key Detection

Detects key ghosting automatically — when your keyboard stops registering a key that is still physically held. The ghost alert fires when the live count drops below your established peak while the same keys remain pressed. Ghosting is caused by keyboard matrix limitations on budget and mid-range boards.

Gaming Combo Verification

Nine preset gaming and productivity key combinations test specific rollover scenarios — from basic WASD to 9-key NKRO stress tests. Each combo auto-detects whether all required keys registered simultaneously, giving you a pass/fail result for real-world use cases like FPS, MMO, rhythm games, and code editors.

Rollover Grade Classification

Automatically classifies your keyboard's rollover: Poor (2KRO), Adequate (6KRO), Good (10KRO), or Excellent (NKRO). The grade updates live as you reach new peak simultaneous key counts. Use this to verify whether your keyboard's advertised NKRO specification matches its actual performance.

Live Visual Keyboard

Every key pressed lights up red on a visual keyboard layout in real time. The hero keyboard preview at the top of the page also lights up as you type — giving you immediate visual confirmation of which keys are registering. Keys stay highlighted while held and return to default on release.

Key Event Log & History

Every keydown and keyup event is logged with a millisecond timestamp and the key's code. The Key History tab records every simultaneous combination that reached 2 or more keys — letting you review your test session and export which combos your keyboard handled successfully.

How to Run the Key Rollover Test

How to Use the Free Online Key Rollover Tester

Determine your exact NKRO limit in under 2 minutes — no download, no install, works in any modern browser.

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Open and Focus the Test Area

On the Rollover Test tab, click inside the grey test area to give it keyboard focus. The border will turn red to confirm focus is active. Without focus, keys may not register in the test. If keys are still not registering, click directly inside the test box again — some browsers require an explicit click inside the focused element before capturing keyboard events.

Click the test areaRed border = focusedAny modern browser
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Hold Keys Simultaneously

Begin pressing and holding multiple keys at the same time. Start with 2–3 keys, then progressively add more without releasing. Watch the live counter at the top — it shows exactly how many keys are registered at this moment. Hold W, A, S, D together first. Then add Shift, Space, Ctrl, and more. The peak number shown is your current best rollover count.

Start with WASDAdd keys one by oneDon't release yet
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Find Your Rollover Limit

Keep adding keys while holding all previous ones. Watch the live counter carefully. When the count stops increasing even as you press additional keys, you have reached your keyboard's rollover limit. The last number before it stopped increasing is your NKRO value. If the count drops while you are still holding keys, ghosting has occurred — your keyboard's matrix cannot handle that specific combination.

Counter stops = limit foundCount drops = ghostingPeak = your NKRO
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Test Gaming Combos

Switch to the Gaming Combos tab after running your basic rollover test. Each combo card shows a specific key combination used in real games and productivity apps. Hold the listed keys in the rollover area — the combo card automatically updates to show pass or fail when those exact keys are detected as held simultaneously. This tells you whether your keyboard handles real-world scenarios, not just raw key counts.

9 preset combosAuto pass/failFPS, MMO, Rhythm
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Read Your Grade

Check the Rollover Grades tab for a complete breakdown of all rollover types and what each means for your use case. Your keyboard's classification (2KRO through Full NKRO) appears live in the stats bar at the top. If your keyboard is advertised as NKRO but only reaches 6 on this test, it may be operating in USB boot mode — check for an NKRO toggle in your keyboard's companion software or a dedicated hardware key combination.

2KRO = basic6KRO = adequateNKRO = unlimited
Why Use This Key Rollover Tester

Why Choose Gamepad Tester for Your Key Rollover Test

Instant — Zero Install

Open in any modern browser and test immediately. No download, no driver software, no account required. Works on Windows, macOS, Linux, and Chromebook with Chrome, Firefox, Edge, and Safari. The entire key rollover tester runs locally in your browser.

Automatic Ghost Detection

Most key rollover testers only count simultaneous keys — this tool also automatically detects and flags ghosting and blocking events in real time. When a held key drops out unexpectedly, the alert fires immediately so you know exactly when and where your keyboard's matrix is failing.

Real-World Gaming Combos

Nine preset combo tests cover the actual key combinations used in FPS, MMO, rhythm games, and code editors — not just abstract simultaneous counts. This tells you whether your keyboard passes or fails at the specific inputs your games require, not just whether it reaches a number in a lab test.

Live Visual Keyboard Display

Every keypress lights up on a visual keyboard layout in real time — both in the hero section and in the test area. Visual confirmation makes it immediately clear which keys are registering and which are being silently dropped by the keyboard's matrix without any numbers required.

100% Private — No Data Sent

Every keystroke you press stays on your device. No key inputs, combinations, or test results are sent to any server. The rollover tester runs entirely in your browser using local JavaScript event listeners. Your typing patterns and key combinations remain completely private.

Works with All Keyboard Types

Mechanical keyboards, membrane keyboards, gaming keyboards, laptop built-in keyboards, wireless keyboards, and USB hubs all work identically from the browser's perspective. The rollover test reads native browser keyboard events — no HID driver or manufacturer software required.

Frequently Asked Questions

Key Rollover Test FAQs

What is key rollover and what does the test measure?
Key rollover is the number of keys your keyboard can register simultaneously. When you press more keys than your keyboard's rollover limit, one of two problems occurs: ghosting (a key that is physically held is not reported to the computer) or blocking/jamming (additional keypresses are completely ignored). This test measures your exact rollover limit by tracking how many simultaneous keys are registered through the browser's keyboard event system. Your peak simultaneous key count during the test is your keyboard's effective NKRO value.
What is the difference between 2KRO, 6KRO, and NKRO?
2KRO (2-Key Rollover) means only 2 keys register at once — standard on cheap membrane keyboards. Pressing 3 keys causes ghosting. 6KRO (6-Key Rollover) is the USB HID Boot Protocol standard — 6 simultaneous non-modifier keys. Most gaming keyboards without an explicit NKRO label are 6KRO. This handles the majority of gaming scenarios but can fail on complex 6+ key combos. NKRO (N-Key Rollover) means unlimited simultaneous key registration — every key on the keyboard is independently scanned and reported regardless of how many others are held. This is the gold standard for competitive gaming, rhythm games, fast typing, and professional use. Note: modifier keys (Shift, Ctrl, Alt) are typically handled separately and do not count toward the rollover limit on any tier.
Why does my keyboard only reach 6 keys even though it is advertised as NKRO?
Many keyboards that advertise NKRO only achieve it in a specific mode. Over USB, the default HID Boot Protocol limits keyboards to 6 simultaneous keycodes. Full NKRO over USB requires the keyboard to use an extended HID report format, which some keyboards only activate when NKRO mode is toggled. Check your keyboard's manual for an NKRO activation key combination — common shortcuts include Gaming Mode toggle, a dedicated NKRO button, or holding Fn plus a specific key during connection. PS/2 connections natively support full NKRO without any software toggle. If your keyboard has companion software like Razer Synapse or Corsair iCUE, NKRO may be a toggle in the settings.
What is key ghosting and how is it different from blocking?
Ghosting is when pressing a combination of keys causes a key you did not press to appear as pressed — a phantom input. This happens because the keyboard matrix cannot disambiguate which switch caused an electrical signal when multiple circuits are activated simultaneously. Blocking (also called jamming) is when pressing certain key combinations causes one or more of your actual presses to simply not register — a missing input. Both are caused by keyboard matrix design limitations in keyboards without full anti-ghosting. Anti-ghosting typically adds a diode to every key in the matrix, preventing phantom signals. NKRO keyboards with dioded matrices are inherently anti-ghosting because the diodes prevent the cross-circuit conditions that cause ghost inputs.
Does key rollover matter for gaming?
Yes, significantly in specific game genres. FPS games like CS2, Valorant, and Apex Legends frequently require 5–6 simultaneous key presses — diagonal movement (W+A or W+D), sprint (Shift), jump (Space), and interact (E or F). A 2KRO keyboard fails here. Rhythm games like osu! and StepMania require 4–8+ simultaneous key presses in rapid succession for chord patterns — only 6KRO or NKRO keyboards handle these correctly. MMOs and MOBAs require ability combos with number row plus modifiers. For general FPS and gaming, 6KRO is usually sufficient. For rhythm games, fast typing, competitive gaming where every input matters, or any game with 6+ key combos, full NKRO is recommended.
Why are some keys blocked in the test (like PrintScreen or Windows key)?
Some keys are intercepted by the operating system or browser before they reach this page. The Windows/Super key is captured by the OS for system shortcuts and cannot be read by browser applications. PrintScreen is similarly OS-level on most systems. Some F-keys (especially F1–F4) may trigger browser actions like Help, Bookmarks, or Developer Tools before the keydown event reaches the page. The Escape key may exit full screen or cancel browser focus. These are not keyboard failures — they are OS and browser design limitations. On macOS, the Command key behaves similarly to the Windows key. For the most accurate results, focus the test area before testing and avoid key combinations that trigger OS-level actions.
Does this key rollover test work with wireless and Bluetooth keyboards?
Yes — this tester reads standard browser keyboard events which are connection-agnostic. USB, 2.4GHz wireless, and Bluetooth keyboards all produce identical keyboard events in the browser. However, wireless keyboards may have a lower effective NKRO than their wired specification because some manufacturers reduce the report rate or simplify the HID descriptor for wireless mode to reduce power consumption and latency. If you notice your wireless keyboard achieves fewer simultaneous keys than its wired specification, try connecting via USB to compare. Low battery can also affect simultaneous key registration on some wireless keyboards as the radio transmission may drop input reports under power constraints.
My keyboard says anti-ghosting but still fails the test. Why?
Anti-ghosting is marketing terminology that is often misused. True anti-ghosting using diodes on every key switch prevents phantom inputs but does not necessarily increase the rollover limit. A keyboard can be anti-ghosting (no phantom keys) but still 6KRO (only 6 simultaneous keys). Anti-ghosting in advertising sometimes refers only to specific key zones — such as the WASD area plus common gaming keys — rather than the entire keyboard. Zone-based anti-ghosting means only those specific key clusters have diodes, while the rest of the keyboard still has full ghosting potential. Full NKRO with a fully-dioded matrix is the only specification that guarantees both no ghosting and unlimited simultaneous key registration across the entire keyboard.
How do I fix key ghosting on my keyboard?
Key ghosting is a hardware design limitation of the keyboard matrix — it cannot be fixed through software, driver updates, or cleaning. The only solutions are: use a keyboard with full NKRO (fully dioded matrix), toggle NKRO mode if your keyboard supports it via firmware or companion software, switch to a PS/2 connection if your keyboard and motherboard support it (PS/2 natively supports full NKRO), or remap your key combinations to avoid the specific matrix positions that conflict on your current keyboard. For competitive gaming, upgrading to a confirmed NKRO mechanical keyboard is the definitive solution. Budget mechanical keyboards in the $50–$80 range from brands like Keychron, Ducky, and Varmilo typically offer full NKRO over USB.
Is this key rollover test free and does it store my keystrokes?
This key rollover tester is completely free — no download, no installation, no account, no email required. It runs entirely in your browser. No keystroke data is sent to any server. The keyboard event listener runs locally in JavaScript — your key presses, combinations, and timing data never leave your device. You can use this tool as many times as needed, on any device, without any restrictions or data collection. The entire test — simultaneous key counting, ghosting detection, combo checking, and the event log — is processed client-side only.

Gamepad Tester — free browser-based key rollover test tool. Check keyboard NKRO, anti-ghosting, simultaneous key detection, and ghost key detection. Works with all mechanical, membrane, gaming, and wireless keyboards. No download required. Compatible with Chrome, Firefox, Edge, and Safari. All keystrokes processed locally — fully private.  ·  ← Back to Gamepad Tester  ·  Mouse Test →