File transfer time calculator
Calculator
Transfer time is file size divided by connection speed: a file's size in bits, divided by the bits per second your connection carries. Enter the size and your upload speed (not the download speed your plan advertises) and the answer below updates instantly.
Upload time
13 min 20 s
Uploading a 10 GB file on a 100 Mbps connection takes about 13 minutes 20 seconds.
100 Mbps ≈ 12.5 MB/s. Assumes the speed holds for the whole transfer; turn on protocol overhead for a more realistic figure.
Transfer times for common file sizes and speeds
Both tables follow your inputs. The first keeps your speed and varies the file size; the second keeps your file size and varies the speed. Every row is also written out as a sentence under "In words".
| File size | Time at 100 Mbps |
|---|---|
| 1 GB | 1 min 20 s |
| 5 GB | 6 min 40 s |
| 10 GB | 13 min 20 s |
| 20 GB | 26 min 40 s |
| 50 GB | 1 h 6 min |
| 100 GB | 2 h 13 min |
| 1 TB | 22 h 13 min |
In words
- Uploading 1 GB at 100 Mbps takes about 1 minute 20 seconds.
- Uploading 5 GB at 100 Mbps takes about 6 minutes 40 seconds.
- Uploading 10 GB at 100 Mbps takes about 13 minutes 20 seconds.
- Uploading 20 GB at 100 Mbps takes about 26 minutes 40 seconds.
- Uploading 50 GB at 100 Mbps takes about 1 hour 6 minutes.
- Uploading 100 GB at 100 Mbps takes about 2 hours 13 minutes.
- Uploading 1 TB at 100 Mbps takes about 22 hours 13 minutes.
| Connection speed | Time for 10 GB |
|---|---|
| 10 Mbps | 2 h 13 min |
| 25 Mbps | 53 min 20 s |
| 50 Mbps | 26 min 40 s |
| 100 Mbps | 13 min 20 s |
| 500 Mbps | 2 min 40 s |
| 1000 Mbps | 1 min 20 s |
In words
- Uploading 10 GB at 10 Mbps takes about 2 hours 13 minutes.
- Uploading 10 GB at 25 Mbps takes about 53 minutes 20 seconds.
- Uploading 10 GB at 50 Mbps takes about 26 minutes 40 seconds.
- Uploading 10 GB at 100 Mbps takes about 13 minutes 20 seconds.
- Uploading 10 GB at 500 Mbps takes about 2 minutes 40 seconds.
- Uploading 10 GB at 1000 Mbps takes about 1 minute 20 seconds.
Typical upload speeds by connection type
Most home and mobile connections are asymmetric: the advertised number is the download speed, and the upload speed, the one that matters when you are sending a file, is often a tenth of it. A "100 Mbps" cable plan that uploads at 10 Mbps sends a 10 GB file in about 2 hours 13 minutes, not 13 minutes. Run a speed test and enter the upload figure above. Ranges below are typical real-world figures, not guarantees.
| Connection | Typical download | Typical upload |
|---|---|---|
| ADSL / ADSL2+Copper phone line; uploads are a tiny fraction of downloads. | 8–24 Mbps | 0.5–1 Mbps |
| Cable (DOCSIS 3.x)Fast down, but upload is usually capped at 5–10% of the download tier. | 100–1,000 Mbps | 10–50 Mbps |
| FTTC / VDSLFibre to the cabinet, copper for the last stretch. | 40–80 Mbps | 10–20 Mbps |
| Full fibre (FTTP)Often symmetric; the only home connection where uploads match downloads. | 100–1,000+ Mbps | 100–1,000 Mbps |
| 4G / LTEVaries with signal and congestion; expect the low end indoors. | 20–100 Mbps | 5–30 Mbps |
| 5GStrong in cities; upload is still well below download. | 100–1,000 Mbps | 20–100 Mbps |
| StarlinkSatellite; upload is consistently the slow direction. | 50–250 Mbps | 10–30 Mbps |
| Office leased lineSymmetric and uncontended; the stated speed is what you get. | 100 Mbps–10 Gbps | 100 Mbps–10 Gbps |
What if the connection drops?
Long transfers rarely run uninterrupted: Wi-Fi roams, laptops sleep, mobile networks hand over between masts. A transfer that cannot resume restarts from zero and the whole estimate above starts again. With a resumable transfer only the part in flight is re-sent, so the time lost is seconds. HeftySend uploads are resumable by default; the single button below takes you to the uploader.
Popular calculations
Written-up answers for the file sizes and connection speeds people ask about most: what the size and the speed really are, the same file at nearby speeds, the same speed for nearby sizes, the effect of protocol overhead and the upload-versus-download catch.
Sending something big? Let it survive a dropped connection.
HeftySend uploads in parts and resumes from the last confirmed part, so a Wi-Fi blip or a sleeping laptop costs seconds, not the whole transfer. No account needed for transfers up to 100 GB.
Send up to 100 GB freeHow this is calculated
Transfer time is the number of bits to move divided by the bits per second the connection carries. The calculator converts the file size to bits, the speed to bits per second, divides, and optionally adds protocol overhead. The same formula applies to uploads and downloads; only the speed you enter differs.
Formula
time (seconds) = file size (bytes) × 8 ÷ connection speed (bits per second)
with protocol overhead: time × 1.10
example: 10 GB = 80,000,000,000 bits ÷ 100,000,000 bits/s = 800 seconds = 13 minutes 20 seconds
Assumptions
- Decimal units: 1 KB = 1,000 bytes, 1 MB = 1,000,000 bytes, 1 GB = 1,000,000,000 bytes and 1 TB = 1,000,000,000,000 bytes, the convention internet providers, drive manufacturers and macOS use.
- Mbps and Gbps are bits per second (1 Mbps = 1,000,000 bits per second); MB/s is bytes per second, eight times larger. 100 Mbps = 12.5 MB/s.
- The speed you enter is sustained for the whole transfer with nothing else using the connection.
- The optional protocol overhead adds 10%: TCP/IP headers, TLS and HTTP framing typically cost 5–10% of the raw link rate.
- Durations are rounded to the two largest units (for example 2 hours 13 minutes).
What the estimate does not cover
- Wi-Fi losses, network congestion, ISP throttling and the receiving server's own speed limits.
- Time spent zipping, compressing or checksumming files before they are sent.
- Retransmissions after a dropped connection; a non-resumable upload starts again from zero.
- Binary (GiB) sizes: a file Windows reports as 10 GB is about 10.74 decimal GB, roughly 7% more than the figure entered.
Frequently asked questions
How long does it take to upload 10 GB?
About 13 minutes 20 seconds at 100 Mbps, 1 hour 6 minutes at 20 Mbps (a typical cable or 4G upload speed) and 1 minute 20 seconds at 1 Gbps. Put your own upload speed into the calculator; it is usually far lower than the download speed your plan advertises.
How long does it take to upload 100 GB?
About 2 hours 13 minutes at 100 Mbps, 11 hours 6 minutes at 20 Mbps and 13 minutes 20 seconds at 1 Gbps, before protocol overhead. On an ADSL line at 1 Mbps the same 100 GB would take 9 days 6 hours.
How long does it take to transfer 1 TB?
About 22 hours 13 minutes at 100 Mbps, 2 hours 13 minutes at 1 Gbps and 4 days 15 hours at 20 Mbps. Transfers this large almost always span a connection drop or a sleeping laptop, so use a resumable upload.
Why is my real upload slower than the calculator says?
The calculator assumes the speed you enter is sustained for the whole transfer. Real uploads lose 5–10% to TCP, TLS and HTTP framing (turn on the protocol-overhead option), and home connections are asymmetric: a 100 Mbps cable plan often uploads at 10–20 Mbps. Wi-Fi, other devices on the network, a slow disk and the receiving server's own limits can all cap throughput. Run a speed test and use the upload figure, not the download figure.
What is the difference between Mbps and MB/s?
Mbps is megabits per second and MB/s is megabytes per second. One byte is 8 bits, so 100 Mbps equals 12.5 MB/s. Internet plans are sold in megabits; file sizes are measured in bytes, which is why a 100 Mbps connection moves about 12.5 MB of file data per second, not 100 MB.
Is 1 GB 1,000 MB or 1,024 MB?
This calculator uses decimal units: 1 GB = 1,000 MB = 1,000,000,000 bytes, the convention used by internet providers, drive manufacturers and macOS. Windows reports sizes in binary units (1 GiB = 1,073,741,824 bytes) but labels them GB, so a file Windows calls 10 GB is about 10.74 decimal GB and takes roughly 7% longer than the decimal figure suggests.
What happens if my connection drops during a large upload?
A plain browser upload starts again from zero. HeftySend uploads in parts and resumes from the last confirmed part when the connection comes back, so a dropped connection costs seconds rather than the whole transfer. Transfers up to 100 GB are free and need no account.