DSL Speed Test
Click start and the adaptive engine measures ping, download and upload in under a minute — with no account and no app.
How the measurement works
The measurement engine begins with tiny requests and grows the transfer size stepwise, so the total data moved is close to the minimum needed for a confident number.
Instead of forcing one fixed download on everyone, the tool adapts: it sends progressively larger payloads and stops the moment the estimate stabilizes.
Adaptive testing also means the test is gentle on mobile data plans: it stops transferring as soon as the estimate is statistically stable.
What the numbers mean
A higher download number means quicker page loads and smooth 4K streaming; upload matters for video calls, backups and large file sends.
Ping is measured over many small round trips, and the result you see is the median of all of them, so an occasional slow packet does not distort the reading.
What affects your speed
A test reaches a steady state only after TCP congestion control ramps up, which is why very short downloads can under-report fast connections — this test's ladder avoids that by using progressively larger payloads.
This service measures the path to Cloudflare's edge, which is close to how your ISP peers with the broader internet — a fair general baseline.
A few final tips
The result screen labels the server you measured against, so you always know exactly what path a number represents before you compare it with anything else.
Run the test a few times over a few days before drawing conclusions. One-off speeds are noisy; a median of several runs is a much more reliable picture of your connection.
Your data stays in your browser for the duration of the test; only a small, anonymous summary is saved afterward, and never the raw payload.
Making the result useful
DSL Speed Test is built to run on your connection in under a minute — press start, read the four numbers, and compare them with what your plan promises.
Speed test limitations
Upload speeds can be throttled or capped separately from downloads on some plans, so a fast download with a slow upload is often the plan working as designed rather than a fault.
A single measurement is a snapshot. Network traffic, time of day and local congestion all shift results, which is why comparing a few runs across different days is more meaningful than any one number.
Related tests & guides
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