Live Stream Upload Speed Calculator
Estimate the upload speed you need when you stream live to a service such as YouTube Live. Add a safety margin for headroom, and compare the result with the upload speed you measured.
What this tool covers (the upload side)
This tool calculates the speed of the upload connection, the side where you send video to a streaming service such as YouTube Live. The service delivers the stream to your viewers, so the upload speed you need does not grow with the number of viewers. It depends on the bitrate and the number of streams you send.
How it is calculated
- Bitrate of one stream = video bitrate + audio bitrate
- Total bitrate = bitrate of one stream × number of simultaneous streams
- Estimated required upload speed = total bitrate × (1 + safety margin ÷ 100)
Video and audio are entered separately and added together. The prefixes k, M and G are powers of 1,000 (1 Mbps = 1,000,000 bits per second). For the difference between units such as bps and MB/s, see the Bitrate Calculator.
About the number of streams
The number of streams is the number of independent streams you send from the same connection.
- Sending to two streaming services at the same time with separate encoder settings: 2 streams.
- Sending one video to a service that re-streams it to several sites: you send 1 stream. The number of re-streaming destinations is not counted.
A 0% safety margin, and what is not included
- The safety margin starts at 0%, and that result is the theoretical amount of data sent. It does not guarantee a stable stream. 0% is the minimum speed needed to send the bitrate as it is.
- The safety margin is the percentage you add when you want headroom. With 50%, the estimate is 1.5 times the calculated value. How much headroom you need depends on your connection and the recommendations of your streaming service. The tool does not set a figure for you, so check the service's recommended conditions too.
- Momentary changes in connection speed, protocol overhead and packet loss are not included. In practice these can make you need more speed than the calculated value.
Comparing with a measured upload speed
If you enter a measured upload speed (for example from a speed test), the tool shows two figures:
- Headroom against the estimated requirement (by calculation): the measured upload speed minus the estimated required upload speed with the safety margin. When it is negative, you are short by that amount, by calculation.
- Share of the measured connection used by the stream: the total bitrate as a percentage of the measured upload speed. It is calculated with the bitrate sent, without the safety margin. Above 100%, the measured speed cannot carry the data, by calculation.
A speed test result alone cannot guarantee that a stream will be stable. Measured speeds change with the time of day, the measuring method, congestion, wireless conditions and equipment. This comparison also leaves out momentary changes in speed, protocol overhead and packet loss. A measured value at or above the estimate does not mean the stream will be stable. Measure several times and check how much the results vary.
Examples
- Video 6 Mbps + audio 160 kbps: 6.16 Mbps for one stream.
- Two streams at the same time: 12.32 Mbps. With a 50% safety margin, 18.48 Mbps.
- A measured upload speed of 30 Mbps: the headroom is 11.52 Mbps by calculation (30 − 18.48), and the stream uses about 41.07% of the connection (12.32 ÷ 30, without the safety margin).
- A measured 10 Mbps with a 0% safety margin (12.32 Mbps needed): 2.32 Mbps short by calculation, and the stream uses 123.2% of the connection.
Notes
- The video bitrate must be greater than 0. The audio bitrate is 0 if left empty. Decimals are allowed (up to 12 digits before the decimal point and 6 decimal places). Use a period as the decimal separator; commas are accepted only as thousands separators.
- The number of streams is 1 to 20, and the safety margin is 0 to 1,000%. You can calculate without a measured upload speed.
- If you send several qualities from the same connection (for example for adaptive streaming), add up the bitrates of each quality, or enter each as a stream.
- For the time a file takes to transfer, see the File Transfer Time Calculator. For the relation between video size and bitrate, see the Video File Size Calculator.
Frequently asked questions
Do I need a faster upload when I have more viewers?
Not when you stream to a service such as YouTube Live. The service delivers the stream to the viewers. The upload speed you need depends on the bitrate and the number of streams you send.
Is an upload speed equal to the bitrate enough?
The result with a 0% safety margin is the theoretical minimum. In practice, changes in speed, protocol overhead and packet loss mean it may not be enough exactly. Leave some headroom.
How many streams is it when the service re-streams to several sites?
You send 1 stream. The re-streaming is done on the service's side, so it is not counted.
If my measured upload speed is above the estimate, will the stream be stable?
It cannot be guaranteed. A speed test shows the speed at the moment you measured it, which varies with the time of day, congestion, wireless conditions and equipment. Momentary changes in speed, protocol overhead and packet loss are not in this calculation. Use the result as a guide, leave headroom, and test with a trial stream.
How do I measure my upload speed?
Use a speed test service and read the upload (not the download) speed. Measure on the equipment and connection you stream with, at a time close to when you will stream.