Disk Speed Test — Free Online
Test your SSD, HDD, or NVMe drive speed directly in your browser — no app installation required. Free DVL DiskMark-style online benchmark
Storage Benchmark
Measure sequential and random read/write speeds with DVL DiskMark-style test profiles
This test uses the File System Access API to write/read real files on your drive. Works best on Chrome/Edge desktop. Select a folder — no data will be modified outside the test file.
Android Chrome and iOS Safari have limited support — results may be lower than desktop.
Select a drive to test
Select a folder — no data will be modified outside the test file
Select a folder and click Start
How It Works
Click 'Select Folder' to choose any empty folder on your drive. The benchmark creates a temporary test file and runs eight DVL DiskMark-style tests: sequential 1MB reads/writes (queue depths 1 and 8) and random 4K reads/writes (queue depths 1 and 32). Results are displayed in real time. The temporary file is automatically deleted when the test completes.
About DVL DiskMark Tests
DVL DiskMark is the industry standard for storage benchmarks. Our online version tests the same four profiles: SEQ1M Q8T1 (sequential 1MB blocks, 8 queued requests), SEQ1M Q1T1 (single-threaded sequential), RND4K Q32T1 (random 4KB with deep queue), and RND4K Q1T1 (single-queue random). These tests reveal your drive's peak throughput (sequential) and latency characteristics (random 4K) — key metrics for OS responsiveness and large file transfers.
Frequently Asked Questions
Does this test write files to my drive?
Yes. The test creates a temporary file (~256MB) in your selected folder to measure real disk performance. The file is automatically deleted when the test completes. No other files are modified.
Why do I need to select a folder?
The File System Access API requires you to explicitly grant permission via the folder picker. This is a security feature — no website can access your files without your consent.
What is the difference between SEQ and RND?
SEQ (Sequential) tests measure large-file transfer speeds — useful for copying movies, games, or backups. RND (Random 4K) tests measure small-file access latency — critical for OS boot times, app loading, and database performance.
What does Queue Depth (Q) mean?
Queue Depth is the number of I/O requests the drive processes simultaneously. Higher queue depths (Q8, Q32) show the drive's maximum throughput. Lower queue depths (Q1) show single-request latency — more relevant for everyday tasks.
Why are my results lower than DVL DiskMark?
This web test uses the File System Access API which has overhead compared to native apps. Results may be 10-30% lower than DVL DiskMark. Use this for relative comparisons — the same drive tested multiple times should give consistent results.
Does this work on mobile?
The File System Access API requires a desktop browser (Chrome/Edge). On mobile, you can still run a memory-based performance test that measures your device's RAM throughput.
What's a good result?
For modern SSDs: SEQ read > 2000 MB/s (NVMe) or > 500 MB/s (SATA). For HDDs: SEQ read 100-200 MB/s. RND4K: > 40 MB/s (good NVMe), 10-30 MB/s (SATA SSD), < 2 MB/s (HDD).
Tips for Accurate Results
- Close other applications before testing
- Run the test 2-3 times and take the average
- Test on an empty or near-empty folder
- Ensure your device is plugged in (not on battery)
- SSD performance drops when the drive is near full
- For best results, test a drive with at least 10% free space