Data Transfer Unit Converter

How to use this calculator

Three inputs. All of them matter.

Speed is the number you’re starting with. Type it in the field. Decimals work fine — 1.5, 0.25, 100, 1000 are all valid.

From unit is the unit your number is expressed in. The dropdown covers every common data transfer unit: bps, Kbps, Mbps, Gbps on the bits side; B/s, KB/s, MB/s, GB/s on the bytes side. Pick the one that matches your source.

To unit is the unit you want. Same options. Pick your target.

Click Calculate and the blue results panel shows your converted speed plus four additional outputs: Megabits per second (Mbps), Megabytes per second (MB/s), estimated time to download 1 GB in seconds, and time to download 1 GB in minutes. Those download time estimates are the most immediately useful outputs — they translate an abstract speed number into something you can actually feel.

What problem this calculator solves

Data transfer speeds live in two parallel universes that never explain themselves to each other.

Network engineers, ISPs, and hardware manufacturers measure bandwidth in bits per second (bps, Kbps, Mbps, Gbps). This makes their numbers look larger, which is convenient for marketing. A 1 Gbps fiber connection sounds impressive.

Operating systems, download managers, and file transfer tools display speed in bytes per second (B/s, KB/s, MB/s, GB/s). Since 1 byte = 8 bits, these numbers are always one-eighth the size of the equivalent bits figure.

So your 1 Gbps fiber plan delivers 125 MB/s of actual file transfer speed — which is still excellent, but it’s the number your download manager will show you, and it looks 8x smaller than the plan you paid for.

Neither measurement is wrong or misleading in isolation. But seeing them side by side without context creates real confusion about whether your connection is performing correctly.

The bits vs bytes problem, explained simply

Eight bits make one byte. Always. This is fixed. It doesn’t vary by context, by country, or by the device you’re using.

A bit is the smallest unit of digital information: a 0 or a 1. A byte is a group of 8 bits. Text files, images, videos, and executables are all measured in bytes (or kilobytes, megabytes, gigabytes). Network transmission capacity is measured in bits per second.

Your ISP sold you bandwidth in bits. Your operating system measures file sizes in bytes. To find your real download speed in the units you can verify with a progress bar, divide your connection speed in Mbps by 8.

This is the single most common source of confusion in internet speed testing. Someone on a 50 Mbps connection wonders why downloads top out at around 6 MB/s instead of 50 MB/s. They assume something is wrong. The connection is fine. 50 ÷ 8 = 6.25 MB/s, exactly as expected.

The prefix problem: kilo, mega, giga in networking

One more layer of complexity: the prefixes kilo (K), mega (M), and giga (G) mean slightly different things depending on whether you’re talking about data storage or data transfer rates.

In networking and data transfer: 1 Kbps = 1,000 bps. 1 Mbps = 1,000,000 bps. 1 Gbps = 1,000,000,000 bps. These are decimal (SI) prefixes. The calculator uses these.

In data storage: 1 KB is sometimes 1,024 bytes (binary prefix, abbreviated KiB properly), and sometimes 1,000 bytes depending on whether you’re reading a hard drive manufacturer’s spec or an operating system’s file size. This is a separate debate that doesn’t affect speed conversion but does affect file size calculation.

This calculator uses decimal prefixes throughout (1 Kbps = 1,000 bps, 1 Mbps = 1,000,000 bps), which matches how ISPs, router manufacturers, and network equipment rate their speeds.

Master conversion table: all units to Mbps and MB/s

The single most useful reference. Every common speed value converted to the two units you’ll see most often.

From	Value	Mbps	MB/s	Equivalent in bps
bps	1	0.000001	0.000000125	1
bps	1,000	0.001	0.000125	1,000
Kbps	1	0.001	0.000125	1,000
Kbps	56	0.056	0.007	56,000
Kbps	128	0.128	0.016	128,000
Kbps	512	0.512	0.064	512,000
Mbps	1	1.00	0.125	1,000,000
Mbps	5	5.00	0.625	5,000,000
Mbps	10	10.00	1.25	10,000,000
Mbps	25	25.00	3.125	25,000,000
Mbps	50	50.00	6.25	50,000,000
Mbps	100	100.00	12.50	100,000,000
Mbps	300	300.00	37.50	300,000,000
Mbps	500	500.00	62.50	500,000,000
Gbps	1	1,000.00	125.00	1,000,000,000
Gbps	2.5	2,500.00	312.50	2,500,000,000
Gbps	10	10,000.00	1,250.00	10,000,000,000
MB/s	1	8.00	1.00	8,000,000
MB/s	10	80.00	10.00	80,000,000
MB/s	100	800.00	100.00	800,000,000
GB/s	1	8,000.00	1,000.00	8,000,000,000

Download time table: how long does it actually take?

The most practical output from the calculator. Real file sizes against real connection speeds. These assume 100% utilisation — add 20% for a realistic estimate.

Connection speed	1 MB file	100 MB file	1 GB file	10 GB file	1 TB file
1 Mbps (0.125 MB/s)	8 sec	13.3 min	2.2 hr	22.2 hr	93 days
5 Mbps (0.625 MB/s)	1.6 sec	2.7 min	26.7 min	4.4 hr	18.5 days
10 Mbps (1.25 MB/s)	0.8 sec	80 sec	13.3 min	2.2 hr	9.3 days
25 Mbps (3.125 MB/s)	0.3 sec	32 sec	5.3 min	53.3 min	3.7 days
50 Mbps (6.25 MB/s)	0.16 sec	16 sec	2.7 min	26.7 min	1.9 days
100 Mbps (12.5 MB/s)	0.08 sec	8 sec	81 sec	13.3 min	22.2 hr
300 Mbps (37.5 MB/s)	instant	2.7 sec	27 sec	4.4 min	7.4 hr
500 Mbps (62.5 MB/s)	instant	1.6 sec	16 sec	2.7 min	4.4 hr
1 Gbps (125 MB/s)	instant	0.8 sec	8 sec	81 sec	2.2 hr
2.5 Gbps (312.5 MB/s)	instant	0.32 sec	3.2 sec	32 sec	53 min
10 Gbps (1,250 MB/s)	instant	0.08 sec	0.8 sec	8 sec	13.3 min

Real-world speed benchmarks for common technologies

These figures ground the abstract unit conversions in actual hardware and network capabilities.

Technology	Typical speed	In Mbps	In MB/s	Notes
Old dial-up modem	56 Kbps	0.056	0.007	Maximum 56 Kbps; often slower
ADSL (older broadband)	8 Mbps down	8	1.0	Asymmetric; upload much slower
ADSL2+ (improved)	24 Mbps down	24	3.0	Distance-limited from exchange
4G LTE (mobile)	20–150 Mbps	20–150	2.5–18.75	Varies by signal and congestion
5G (sub-6 GHz)	100–900 Mbps	100–900	12.5–112.5	Real-world typical: 150–400 Mbps
5G (mmWave)	1–4 Gbps	1,000–4,000	125–500	Short range, limited availability
Cable internet (DOCSIS 3.0)	200–400 Mbps	200–400	25–50	Shared bandwidth in neighbourhood
Cable internet (DOCSIS 3.1)	500–1,200 Mbps	500–1,200	62.5–150	Multi-gigabit capable
Fibre (GPON)	300–1,000 Mbps	300–1,000	37.5–125	Most residential fibre globally
Fibre (XGS-PON)	2–10 Gbps	2,000–10,000	250–1,250	Next-gen residential fibre
USB 2.0	480 Mbps	480	60	Theoretical; real: ~30–40 MB/s
USB 3.0 / 3.1 Gen 1	5 Gbps	5,000	625	Real: ~300–400 MB/s
USB 3.1 Gen 2	10 Gbps	10,000	1,250	Real: ~800–1,000 MB/s
USB4 / Thunderbolt 3/4	40 Gbps	40,000	5,000	Theoretical maximum
SATA SSD	600 MB/s	4,800	600	Interface limit for SATA
NVMe SSD (PCIe 3.0)	3,500 MB/s	28,000	3,500	Sequential read, typical spec
NVMe SSD (PCIe 4.0)	7,000 MB/s	56,000	7,000	Sequential read, typical spec
Wi-Fi 5 (802.11ac)	433–1,300 Mbps	433–1,300	54–162	Theoretical; real: 200–600 Mbps
Wi-Fi 6 (802.11ax)	600–9,600 Mbps	600–9,600	75–1,200	Multi-antenna, real: 400–1,200
Gigabit Ethernet	1 Gbps	1,000	125	Standard wired home networking
10 Gigabit Ethernet	10 Gbps	10,000	1,250	Server/enterprise networking

Bits per second: the full scale from bps to Tbps

The full range of data transfer speeds spans about 12 orders of magnitude from a single bps to modern backbone links. Seeing the whole scale helps calibrate what your connection figure actually means.

Unit	Abbreviation	In bps	In Mbps	Real-world context
Bits per second	bps	1	0.000001	A single binary signal
Kilobits per second	Kbps	1,000	0.001	Old dial-up, IoT sensors
Megabits per second	Mbps	1,000,000	1	Home broadband unit
Gigabits per second	Gbps	1,000,000,000	1,000	Fibre and enterprise links
Terabits per second	Tbps	1,000,000,000,000	1,000,000	Internet backbone cables
Petabits per second	Pbps	10¹⁵	10⁹	Theoretical/research

The internet’s total global traffic is measured in Petabits per second. A single submarine cable (such as the MAREA cable between the US and Spain) carries around 200 Tbps of capacity. Your 100 Mbps home connection represents about 0.00005% of one cable’s capacity.

Common mistakes when reading speed figures

Confusing Mbps with MB/s. The capitalisation matters. Mbps is megabits per second (lowercase b). MB/s is megabytes per second (uppercase B). A 100 Mbps connection moves 12.5 MB/s of data. If your download manager shows 12.5 MB/s on a 100 Mbps plan, the connection is performing exactly as expected.

Assuming the advertised speed is what you get. ISPs advertise “up to” speeds which represent the physical connection maximum, not the typical delivered speed. Cable internet is shared infrastructure — your neighbourhood’s usage affects your actual throughput, especially during peak hours (typically 7–10 PM). A “300 Mbps” plan might deliver 180 Mbps at 9 PM on a weekday.

Ignoring upload speeds. Most residential internet connections are asymmetric: fast download, slow upload. A 100 Mbps download plan might come with 10 Mbps or 20 Mbps upload. For video calls, file sharing, cloud backup, and working from home, upload speed matters just as much as download. The calculator converts both equally — enter your upload speed separately to see what that means for sending files.

Not accounting for protocol overhead. TCP/IP, the protocol used for most internet data transfer, adds header overhead of around 5–10% per packet. HTTPS encryption adds a small amount more. A 100 Mbps connection has roughly 90–95 Mbps of usable throughput for your actual file data. The rest is protocol overhead.

The bytes-per-second family: conversion table

Bytes-per-second units are what file systems, operating systems, and download managers use. This table converts across the full range.

From	To B/s	To KB/s	To MB/s	To GB/s
1 B/s	1	0.001	0.000001	0.000000001
1 KB/s	1,000	1	0.001	0.000001
1 MB/s	1,000,000	1,000	1	0.001
1 GB/s	1,000,000,000	1,000,000	1,000	1
10 MB/s	10,000,000	10,000	10	0.01
100 MB/s	100,000,000	100,000	100	0.1
500 MB/s	500,000,000	500,000	500	0.5
1,250 MB/s	1,250,000,000	1,250,000	1,250	1.25

And converting from bytes to bits (multiply by 8):

Bytes/s unit	Bits/s equivalent
1 KB/s	8 Kbps
1 MB/s	8 Mbps
10 MB/s	80 Mbps
12.5 MB/s	100 Mbps
62.5 MB/s	500 Mbps
125 MB/s	1 Gbps
1,000 MB/s	8 Gbps

Using the download time output for practical planning

The time-to-download outputs in the calculator make unit conversion immediately useful. Here’s how to extend the 1 GB estimate to any file size.

From the 1 GB time in seconds:

• Time for any file: (file size in GB) × (seconds for 1 GB)
• Time in minutes: divide by 60
• Time in hours: divide by 3,600

Why ISPs advertise in Mbps instead of MB/s

The short answer: larger numbers.

A 100 Mbps plan sounds more impressive than a 12.5 MB/s plan, even though they’re identical. The practice is completely standard and technically accurate — the industry settled on bits per second as the convention for network bandwidth because that’s how physical transmission capacity is measured at the hardware level.

If ISPs advertised in MB/s, a "gigabit" fiber plan would be marketed as "125 MB/s fiber." That's technically accurate and more relatable — 125 MB/s is a number anyone who's moved files around can appreciate. But "1 Gbps" sounds more futuristic. Marketing chose Gbps. It's not going to change.

This creates a persistent gap between what people expect and what they observe. The expectation comes from the advertised Mbps figure. The observation comes from the MB/s figure in the download bar. The gap is always exactly a factor of 8, and it always confuses people who haven’t internalised that conversion.

The calculator makes this gap visible by showing both Mbps and MB/s in the result panel simultaneously.