Speedtest-Lite
Estimate your internet connection speed with download speed, upload speed, and latency (ping) measurements - all using modern web APIs with no Flash or Java required. Run a quick test to verify your ISP performance, troubleshoot connection issues, or check if your connection is suitable for streaming, gaming, and video calls.
Estimate your internet connection speed by downloading a test payload and timing it. Measures download speed, upload speed, and latency - all in your browser.
Press "Start Test" to measure your connection speed
Test may use ~130 KB of data for download test and ~500 KB for upload test. Results are approximate and may vary based on network conditions.
Why Use Our Speedtest-Lite?
Accurate Speed Estimation
Measures download speed by fetching a real file and timing the transfer using the Fetch API and performance timing. Upload speed is measured by generating a test payload and timing the POST request. Latency is measured with multiple HEAD request samples for a median result.
No Flash, Java, or Plugins
Built entirely with modern web APIs - Fetch API, ReadableStream, Performance API, and Crypto API. No plugins, no Flash, no Java required. Works in any modern browser on desktop and mobile.
Test History & Stats
Your test results are saved automatically to localStorage. View your history sorted by date with download speed, upload speed, and latency for each test. Summary stats show your best download, best upload, and average latency across all tests.
Lightweight & Private
The test uses a small publicly available test file (~90 KB) and sends a minimal upload payload (~500 KB). No personal data is collected or transmitted - the tool simply times data transfers to estimate your connection speed.
Common Use Cases for Speedtest-Lite
Verify Your Internet Speed
Quickly check if your internet service provider is delivering the speed you're paying for. Run a test and compare your actual download and upload speeds against your plan's advertised speeds.
Remote Work Readiness
Before important video calls or large file transfers, test your connection to ensure you have sufficient bandwidth. The latency measurement is especially useful for assessing VoIP and video conference quality.
Troubleshoot Connection Issues
Running a speed test can help diagnose slow internet issues. Compare results from different times of day and track your history to identify patterns or verify that fixes have improved your connection.
Compare ISPs & Plans
When choosing between internet service providers or plans, run multiple tests to build a reliable picture of real-world performance. The test history helps you track performance over time.
Gaming & Streaming Checks
Gamers can check latency (ping) which is critical for online gaming. Streamers can verify upload speeds for live streaming quality. The speed rating labels help you quickly assess if your connection is suitable.
Home Network Optimisation
Test your connection from different rooms or devices to identify dead zones or Wi-Fi issues. Run a baseline test near the router, then compare with tests from other locations in your home.
Understanding Our Speedtest-Lite
What is a Speed Test?
A speed test measures the performance of your internet connection by transferring real data between your device and a remote server, then calculating the transfer rate. The three key metrics are download speed (how fast data comes to you), upload speed (how fast data leaves you), and latency (the delay before data starts moving). Our Speedtest-Lite uses the Fetch API and Performance API for all measurements - no plugins needed.
How Our Speed Test Works
- Latency Test: We send 3 HEAD requests to a test server, measuring the round-trip time for each. The median result is reported as your latency (ping). Low latency (under 50ms) is excellent for real-time applications like gaming and video calls.
- Download Test: We fetch a real JPEG image file (~90 KB) using the Streams API, reading the data in chunks and measuring the total time. Download speed is calculated as (total bits transferred) / (duration in seconds), reported in Mbps.
- Upload Test: We generate a 500 KB random payload using the Crypto API and POST it to a test endpoint. Upload speed is calculated the same way as download. If the upload endpoint is unavailable, we estimate upload speed as approximately 30% of your download speed.
Understanding Your Results
- Download Speed (Mbps):How fast you can receive data. Higher is better. 25+ Mbps is good for HD streaming, 100+ Mbps for 4K streaming and large downloads. Rated from Very Fast (>100 Mbps) to Slow (<10 Mbps).
- Upload Speed (Mbps): How fast you can send data. Important for video calls, file uploads, and live streaming. Typically lower than download on most connections.
- Latency (ms): The delay before data transfer begins. Lower is better. Under 20ms is excellent for gaming, under 50ms is good, under 100ms is fair, and over 200ms may cause noticeable lag.
Accuracy & Limitations
Speedtest-Lite provides a reasonable estimate of your connection speed, but results can vary based on many factors: current network congestion, Wi-Fi signal strength, the performance of the test server, and other devices using your connection. For the most accurate results, test while connected via Ethernet and close other bandwidth-heavy applications. The test uses a relatively small payload (~90 KB download, ~500 KB upload) which is sufficient for a quick estimate but may not fully saturate very high-speed connections (500+ Mbps). We use a publicly available Wikipedia image as the test file - if this server is slow, your results may be affected.
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Frequently Asked Questions About Speedtest-Lite
The speed test measures three things: latency (ping) by timing HEAD requests to a server, download speed by fetching a real JPEG file and timing the transfer via the Streams API, and upload speed by generating a random payload and POSTing it to a test endpoint. All measurements use the Fetch API and Performance API.
Speedtest-Lite provides a reasonable estimate of your connection speed. Results can vary based on network congestion, Wi-Fi signal strength, test server performance, and other devices on your network. For best accuracy, use a wired Ethernet connection and close other bandwidth-heavy applications during the test.
The download test uses approximately 90 KB (a small JPEG image). The upload test generates and sends approximately 500 KB of random data. Total data usage is roughly 600 KB per full test - well within typical mobile data allowances.
Download speeds are rated: Very Fast (100+ Mbps), Fast (50-100 Mbps), Good (25-50 Mbps), Fair (10-25 Mbps), and Slow (under 10 Mbps). Latency is rated: Excellent (under 20 ms), Good (20-50 ms), Fair (50-100 ms), Poor (100-200 ms), and Very Poor (over 200 ms).
Most residential internet connections are asymmetric - they offer much higher download speeds than upload speeds. This is normal for cable, DSL, and fibre-to-the-home connections. The upload test may also be affected by the availability of the test endpoint.
Yes. Speedtest-Lite works on any device with a modern browser, including smartphones and tablets. All measurements use standard web APIs that work across Chrome, Safari, Firefox, and Edge on both desktop and mobile.
The test requires network access to download test files and upload test payloads. It may fail if you're offline, behind a restrictive firewall or proxy, or if the test server is temporarily unavailable. Check your internet connection and try again.
Your test results (download speed, upload speed, latency, and timestamp) are saved to your browser's localStorage. This data never leaves your device. You can view your full history and clear it at any time with the "Clear All" button.
Yes, 100% free. There is no signup required, no premium tier, no usage limits, and no ads. Run as many tests as you like for free, forever.