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Bandwidth and download time calculator

Download or upload time for a file at a given speed, the data a link moves in a set time, and a website's monthly bandwidth from page views.

Atualizado Exemplos verificados: 6

Internet plans quote megabits per second (Mbit/s); download dialogs often show megabytes per second (MB/s), 8 times smaller.
%
Share of the line rate lost to packet headers. TCP/IPv4 over Ethernet carries 1460 payload bytes per 1538 bytes on the wire, about 5%.
Experimentar
Transfer time
1 h 10 min 10 s
Transfer time: 1 h 10 min 10 s
Transfer time in seconds
4,210.53s
Data
50GB / 46.566GiB
Payload speed after overhead
95Mbit/s

Moving 50 GB at 100 Mbit/s with 5% overhead takes 1 h 10 min 10 s; speeds are in bits and sizes in bytes, so the size is multiplied by 8 first.

Same transfer at other speeds

10 Mbit/s11 h 41 min100 Mbit/s1 h 10 min1 Gbit/s7 min 1 s10 Gbit/s42.1 sYour 100 Mbit/s1 h 10 min
Como é calculado S

  1. Size in bits

    5×1010 B×8=4×1011 bit5 \times 10^{10}\ \text{B} \times 8 = 4 \times 10^{11}\ \text{bit}

  2. Payload speed

    100 Mbit/s×(1−5%)=95 Mbit/s100\ \text{Mbit/s} \times (1 - 5\%) = 95\ \text{Mbit/s}

    Headers, acknowledgements and retransmissions share the line with your data.

  3. Divide size by speed

    t=4×10119.5×107=4,210.53 st = \frac{4 \times 10^{11}}{9.5 \times 10^{7}} = 4{,}210.53\ \text{s}

Sobre Bandwidth and download time calculator

Transfer time is the size in bits divided by the speed in bits per second: t = 8 × bytes ÷ (rate × (1 − overhead)). The factor of 8 is there because internet plans quote megabits per second while files are measured in bytes. The other two modes run the same equation the other way, for the data a link moves in a set time, or multiply page views by page weight for a website's monthly traffic.

The default, a 50 GB download on a 100 Mbit/s plan with 5% protocol overhead, takes 1 h 10 min 10 s; with no overhead it would take 1 h 6 min 40 s. A site with 100,000 monthly views of a 2 MB page serves 200 GB a month.

Real downloads can be slower than the result when the server, Wi-Fi or a congested route caps the speed below the plan's rate. Sizes follow IEC 80000-13: 1 GB is 10^9 bytes and 1 GiB is 2^30 bytes.

Exemplos resolvidos

50 GB at 100 Mbit/s with no overhead

Quero calcular
Transfer time
Data size
50 GB
Connection speed
100 Mbit/s
Protocol overhead
0%
Transfer time in seconds
4,000 s
Transfer time
1 h 6 min 40 s

Fonte de verificação: Python 3.8: 50e9 × 8 / 100e6 = 4000 s

Same transfer with 5% overhead

Quero calcular
Transfer time
Data size
50 GB
Connection speed
100 Mbit/s
Protocol overhead
5%
Transfer time in seconds
4,210.53 s
Payload speed after overhead
95 Mbit/s

Fonte de verificação: Python 3.8 decimal: 4000 / 0.95 = 4210.526315…

1 GiB at 1 Gbit/s (binary size, edge)

Quero calcular
Transfer time
Data size
1 GiB
Connection speed
1 Gbit/s
Protocol overhead
0%
Transfer time in seconds
8.59 s

Fonte de verificação: Python 3.8: 2**30 × 8 / 1e9 = 8.589934592 s

One hour at 100 Mbit/s

Quero calcular
Data moved in a time
Connection speed
100 Mbit/s
Time spent transferring
1 h
Protocol overhead
0%
Data
45 GB
Data
41.91 GiB

Fonte de verificação: Python 3.8: 100e6 × 3600 / 8 = 45e9 B; 45e9 / 2**30 = 41.90951 GiB

Perguntas

How long does it take to download 1 GB at 100 Mbps?

About 80 seconds at the full line rate: 1 GB is 8,000 megabits, and 8,000 ÷ 100 = 80 s. With 5% protocol overhead it takes about 84 s. At 10 Mbit/s the same file takes 13 min 20 s, and at 1 Gbit/s about 8 s, as long as the server and Wi-Fi keep up.

What is the difference between Mbps and MB/s?

Mbps (megabits per second) measures network speed, while MB/s (megabytes per second) is how browsers and download managers show progress. One byte is 8 bits, so divide Mbps by 8: a 100 Mbit/s plan tops out at 12.5 MB/s, and 1 Gbit/s at 125 MB/s. Protocol overhead lowers the figure you see by a further few percent.

Why is my download slower than my internet speed?

Part of the gap is protocol overhead: over Ethernet, TCP/IPv4 carries 1,460 bytes of data in each full 1,538-byte frame on the wire, so about 5% of the line rate goes to headers, preamble and inter-frame gap. The rest comes from the server's own limit, Wi-Fi signal, congestion on the route, or other devices sharing the connection.

How much bandwidth does a website need per month?

Multiply monthly page views by the average page weight, which your browser's network panel shows. 100,000 views of a 2 MB page is 200 GB a month, about 6.7 GB a day or an average of 0.62 Mbit/s. Visits bunch up in busy hours, so size hosting and caching for several times that average.

Is 1 GB 1,000 MB or 1,024 MB?

Under the SI and IEC 80000-13 prefixes, 1 GB is 1,000 MB, or 10^9 bytes, while 1 GiB (gibibyte) is 1,024 MiB, or 2^30 = 1,073,741,824 bytes. Network speeds and drive labels use decimal units. Windows counts in binary units but labels them GB, so a 50 GB file shows there as 46.57.

Qual é a precisão de “Bandwidth and download time calculator”?

A precisão depende dos dados inseridos e das hipóteses do método. O cálculo decimal usa 50 algarismos significativos, mas estimativas, métodos numéricos e dados de origem podem ter menor precisão; o arredondamento exibido não elimina essas limitações. Exemplos resolvidos verificados com fontes independentes: 6. Por exemplo, “50 GB at 100 Mbit/s with no overhead” é verificado com Python 3.8: 50e9 × 8 / 100e6 = 4000 s.

De onde vem o método?

IEC 80000-13:2008 — decimal (kB, MB, GB) and binary (KiB, MiB, GiB) prefixes for bytes; IEEE 802.3 Ethernet: 8-byte preamble, 14-byte header, 1500-byte payload, 4-byte FCS and 12-byte inter-frame gap (1538 bytes per full frame); NIST — Prefixes for binary multiples.

Sobre esta calculadora

t=8×bytesrate×(1−overhead)monthly=views×page weight\begin{aligned} t &= \frac{8 \times \text{bytes}}{\text{rate} \times (1 - \text{overhead})} \\[4pt] \text{monthly} &= \text{views} \times \text{page weight}\end{aligned}

Fontes

  1. IEC 80000-13:2008 — decimal (kB, MB, GB) and binary (KiB, MiB, GiB) prefixes for bytes
  2. IEEE 802.3 Ethernet: 8-byte preamble, 14-byte header, 1500-byte payload, 4-byte FCS and 12-byte inter-frame gap (1538 bytes per full frame)
  3. NIST — Prefixes for binary multiples

Verificado com as referências

Esta calculadora inclui 6 exemplos resolvidos com respostas de fontes independentes. Eles fazem parte do conjunto de testes e você também pode executá-los aqui.

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