Test Your USB Drive — Detect Fake Capacity & Measure Speed
A free browser-based tool to test USB flash drives for fake capacity. Many cheap drives sold online are counterfeits — a 128 GB drive might only have 8 GB of real storage with firmware that lies about size. This tool writes unique test patterns to your drive and reads them back, detecting fakes exactly like h2testw — without installing any software.
Verify USB drive capacity and expose counterfeit flash drives in your browser
Browser Not Supported
This tool requires the File System Access API, which is only available in desktop Chrome and Edge browsers.
Step 1: Choose a test mode and click the button below to select your USB drive folder.
Step 2: Review settings and start the test. Test files will be created in the selected folder.
Features
How to Test a USB Drive
Insert the USB flash drive into your computer. Make sure it appears in your file explorer.
Choose the USB drive folder from the browser directory picker. Chrome or Edge 86+ required.
Quick Test writes up to 4 GB (fast). Full Test fills the entire drive (thorough).
Watch real-time progress with speed, ETA, and a block-level visualization.
See if your drive is genuine, fake, or degraded — with exact capacity and speed measurements.
Frequently Asked Questions
How do fake USB drives work?
Fake drives have a modified firmware that reports a larger capacity than the physical storage. A 128 GB fake might only have 8 GB of real NAND flash. When you write beyond 8 GB, the controller silently overwrites earlier data. Files appear to save, but are corrupted when you try to read them back.
Is this tool the same as h2testw?
Yes, the principle is identical. Both tools write known data patterns to the drive and verify them by reading back. The difference is that this tool runs in your browser — no Windows installation needed.
Will the test delete my files?
No. The tool creates temporary test files (timbrica_test_*.bin) in a folder you select. Your existing files are not touched. Test files are automatically cleaned up after the test.
Why does it only work in Chrome and Edge?
The tool uses the File System Access API to write and read files directly on your drive. This API is currently only supported in Chromium-based browsers (Chrome, Edge, Opera). Firefox and Safari do not support it yet.
How long does a full test take?
It depends on the drive size and speed. A typical USB 3.0 drive at 30 MB/s takes about 1 hour per 50 GB (write + verify). USB 2.0 drives are much slower — about 1 hour per 10 GB.
Can I test SD cards or external hard drives?
Yes! The tool works with any storage device that appears as a folder in your file system — USB flash drives, SD cards, external HDDs/SSDs, and even network drives.
We can — and it's free! Just send us a quick message with your idea. If you'd like to discuss it in detail, leave your email and we'll get back to you. You can stay anonymous.
