# Ashburn, USA → Johannesburg, South Africa RTT

🇺🇸 **Ashburn, USA (IAD)** → 🇿🇦 **Johannesburg, South Africa (JNB)**

Measurement round: `2026-08-16T04:07:28Z`.

Ashburn to Johannesburg averaged 228.3 ms across 50 replies. The observed range was 216.38 to 264.39 ms; these figures describe one probe round, not a long-term service target.

Standard deviation was 10.74 ms, or 4.7% of the average. This describes variation within the sample without identifying its cause.

## Latency Summary

| Metric               | Value                                                        |
| -------------------- | ------------------------------------------------------------ |
| RTT                  | **228.3 ms**                                                 |
| Jitter               | **7.98 ms**                                                  |
| Packet Loss          | **0%**                                                       |
| Standard Fiber Floor | **128.11 ms**                                                |
| Fiber Efficiency     | **56.1%**                                                    |
| Latency Tier         | Fair                                                         |
| Source Region        | [North America](/docs/network/latency/regions/north-america) |
| Destination Region   | [Africa](/docs/network/latency/regions/africa)               |

## Ping Measurement Series

50 ICMP echo probes were recorded in this round. Individual replies and their distribution are shown below.

## Download This Route's Data

Download the probe round as CSV, JSON or YAML under CC BY 4.0. [Citation details](#about-this-measurement) include the route and round timestamp.

## Theoretical Fiber Latency

The propagation model uses public city-centre coordinates from GeoNames: [Ashburn](https://www.geonames.org/4744870) (39.04372, -77.48749) and [Johannesburg](https://www.geonames.org/993800) (-26.20227, 28.04363). These are not facility coordinates or a surveyed cable path.

| Physical Reference                            | Value         |
| --------------------------------------------- | ------------- |
| WGS-84 geodesic distance                      | **13,082 km** |
| Vacuum RTT floor                              | **87.27 ms**  |
| Standard fiber RTT floor ($n_g=1.4679$)       | **128.11 ms** |
| Low-latency fiber material floor              | **127.59 ms** |
| Engineering floor (5% path allowance)         | **134.53 ms** |
| Research 1.33× mapped-fiber reference         | **170.38 ms** |
| Estimated unamplified path loss               | **2747.2 dB** |
| Transparent optical spans / inline amplifiers | **172 / 171** |
| Published RTT inflation over fiber floor      | **1.78×**     |

The span count assumes 80 km optical spans. Attenuation is a power-loss term, not a propagation delay. See the [model assumptions and equations](/docs/network/latency/theoretical-fiber-latency).

## Stability & Trend

Statistics from the same 50 replies. They describe this probe round, not continuous historical monitoring.

| Round Statistic    | Value         |
| ------------------ | ------------- |
| Minimum RTT        | **216.38 ms** |
| Average RTT        | **228.3 ms**  |
| Maximum RTT        | **264.39 ms** |
| Standard deviation | **10.74 ms**  |
| Stdev / average    | **4.7%**      |

## Route Context

* Departure PoP: [Ashburn (IAD)](/docs/network/latency/iad-ashburn)
* Destination PoP: [Johannesburg (JNB)](/docs/network/latency/jnb-johannesburg)
* Region overview: [North America](/docs/network/latency/regions/north-america) → [Africa](/docs/network/latency/regions/africa)
* Full global matrix: [Backbone Latency Matrix](/docs/network/latency)
* Physical methodology: [Theoretical Fiber Latency](/docs/network/latency/theoretical-fiber-latency)

## Related City-Pair Routes

**Reverse direction**

* [Johannesburg to Ashburn latency and RTT](/docs/network/latency/pairs/jnb-iad-rtt): 229 ms

**Fastest routes departing Ashburn (IAD)**

* [Ashburn to New York latency and RTT](/docs/network/latency/pairs/iad-nyc-rtt): 6 ms
* [Ashburn to Miami latency and RTT](/docs/network/latency/pairs/iad-mia-rtt): 27.4 ms
* [Ashburn to Los Angeles latency and RTT](/docs/network/latency/pairs/iad-lax-rtt): 60.7 ms
* [Ashburn to Seattle latency and RTT](/docs/network/latency/pairs/iad-sea-rtt): 62.3 ms
* [Ashburn to London latency and RTT](/docs/network/latency/pairs/iad-lon-rtt): 70.3 ms

**Fastest routes arriving at Johannesburg (JNB)**

* [Amsterdam to Johannesburg latency and RTT](/docs/network/latency/pairs/ams-jnb-rtt): 171.9 ms
* [Berlin to Johannesburg latency and RTT](/docs/network/latency/pairs/ber-jnb-rtt): 172.1 ms
* [London to Johannesburg latency and RTT](/docs/network/latency/pairs/lon-jnb-rtt): 179.6 ms
* [Paris to Johannesburg latency and RTT](/docs/network/latency/pairs/par-jnb-rtt): 180.9 ms
* [Frankfurt to Johannesburg latency and RTT](/docs/network/latency/pairs/fra-jnb-rtt): 188.4 ms

**Same corridor (North America → Africa)**

* [New York to Johannesburg latency and RTT](/docs/network/latency/pairs/nyc-jnb-rtt): 221.5 ms
* [Miami to Johannesburg latency and RTT](/docs/network/latency/pairs/mia-jnb-rtt): 259.8 ms
* [Seattle to Johannesburg latency and RTT](/docs/network/latency/pairs/sea-jnb-rtt): 282.1 ms

## About This Measurement

These ICMP measurements cover the two backbone endpoints. Access networks, routing policy and load can change an end user's result. A probe round is not an SLA.

The underlying replies are available under **CC BY 4.0** in the [Hats Network latency dataset](/opendata/latency/). Per-pair files are available at `/opendata/latency/latest/pairs/iad-jnb.pings.{csv,json,yaml}`. Cite the route, round timestamp and dataset version. Example: "Hats Network latency dataset, Ashburn → Johannesburg round 2026-08-16T04:07:28Z, CC BY 4.0".

***

*Round published August 16, 2026. See the [full interactive latency matrix](/docs/network/latency) or browse more [city-pair routes](/docs/network/latency/pairs).*

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## License and attribution

- **Canonical source:** [View the human-readable HTML page](https://hatsnet.io/docs/network/latency/pairs/iad-jnb-rtt).
- **Original documentation:** © Hats Network Inc., licensed under [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0/).
- **Public latency data:** © Hats Network Inc., licensed under [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/).
- **Full terms:** [Content and Data License](https://hatsnet.io/docs/legal/content-and-data-license) — includes attribution requirements, third-party material, trademarks, source code and other exclusions.