Free tool · Ethernet
Bandwidth to PPS
bits and packets, both ways.
Convert a bit rate into packets per second, or back, for any Ethernet frame size, with the 20 bytes of preamble and gap counted or left out. Includes a 95th percentile calculator. It all runs in your browser.
FreeNo sign-upNothing stored
Result
10 Gbps at 64-byte frames
64 bytes · Minimum frame
- Packet rate
- 14.88 Mpps · 14,880,952.38 pps
- Bit rate on the wire
- 10 Gbps (frame + 20 bytes)
- Bit rate of the frames
- 7.62 Gbps (header to FCS)
- IP throughput
- 5.48 Gbps (packets of up to 46 bytes)
- Bytes counted per frame
- 84 bytes · 672 bits
- Time per packet
- 67.2 ns
- Line spent on preamble and gap
- 23.8 %
- Counting
- On the wire: preamble, SFD and gap included
The formula, with your numbers
Every frame costs its own bytes plus 20 bytes of preamble, start delimiter and inter-frame gap, times 8 bits. Divide the bit rate by that and you have frames per second.
pps = bit rate ÷ ((frame + 20) × 8)
Bytes per frame on the wire = 64 + 20 = 84
Bits per frame = 84 × 8 = 672
Packets per second = 10,000,000,000 ÷ 672 = 14,880,952.38 ≈ 14.88 Mpps10 Gbps at other frame sizes
| Frame | What it is | Packet rate | Exact pps |
|---|---|---|---|
| 64 B | Minimum frame | 14.88 Mpps | 14,880,952.38 |
| 78 B | TCP SYN with options | 12.76 Mpps | 12,755,102.04 |
| 558 B | 512-byte DNS reply | 2.16 Mpps | 2,162,629.76 |
| 1,518 B | Full 1,500 MTU | 812.74 Kpps | 812,743.82 |
| 9,018 B | 9,000 jumbo | 138.3 Kpps | 138,304.93 |
95th percentile of bandwidth samples
Paste the samples from your graphs or counters, for example one 5-minute average per line. The result follows the usual burstable-billing method: sort, drop the top 5 %, read the highest value left.
One value per line; spaces, tabs and semicolons also separate values. Up to 200,000 samples. Any unit works if you use it throughout.
- 95th percentile
- 240 Mbps
- Peak
- 1,240 Mbps
- Average
- 248.65 Mbps
- Samples
- 40
- Sort the 40 samples from lowest to highest.
- Drop the top 5 %: 40 × 5 % = 2, rounded down to 2 samples.
- The highest value left, number 38 of 40, is the 95th percentile: 240 Mbps.
Reference
Ethernet line rate in packets per second
The most frames a link can carry each second at common speeds, with preamble, start delimiter and the minimum inter-frame gap counted and the result rounded down to whole frames, as RFC 2544 does.
| Link speed | 64-byte frames | 128-byte frames | 512-byte frames | 1,518-byte frames | 9,018-byte frames |
|---|---|---|---|---|---|
| 1 Gbps | 1,488,095 | 844,594 | 234,962 | 81,274 | 13,830 |
| 10 Gbps | 14,880,952 | 8,445,945 | 2,349,624 | 812,743 | 138,304 |
| 25 Gbps | 37,202,380 | 21,114,864 | 5,874,060 | 2,031,859 | 345,762 |
| 40 Gbps | 59,523,809 | 33,783,783 | 9,398,496 | 3,250,975 | 553,219 |
| 100 Gbps | 148,809,523 | 84,459,459 | 23,496,240 | 8,127,438 | 1,383,049 |
| 400 Gbps | 595,238,095 | 337,837,837 | 93,984,962 | 32,509,752 | 5,532,197 |
A 1,518-byte frame carries a full 1,500-byte packet, a 9,018-byte frame a 9,000-byte jumbo packet, and a 64-byte frame up to 46 bytes.
02Guide
How to convert bandwidth to packets per second
Divide the bit rate by the bits each frame occupies on the link. On Ethernet that is the frame size plus 20 bytes, times 8, so 10 Gbps of 64-byte frames is 10,000,000,000 ÷ ((64 + 20) × 8) = 14,880,952 packets per second: the 14.88 Mpps line rate quoted for 10 Gigabit Ethernet. Going the other way, multiply the packet rate by the same number of bits.
Choose whether you start from a bit rate or a packet rate, enter the value with its unit and pick a frame size or one of the presets. The summary next to the form updates while you type; Calculate shows the worked formula, the same rate at other frame sizes and a 95th percentile calculator. Units are decimal, as link speeds are: 1 Gbps is 1,000,000,000 bits per second.
Everything is computed in your browser. Calculate keeps the inputs in the part of the address after the #, which browsers never send to a server, so you can share the link and nothing you typed leaves your device.
Why every frame costs 20 bytes more
Each Ethernet frame is preceded by a 7-byte preamble and a 1-byte start frame delimiter, and followed by an inter-frame gap of at least 12 byte times (96 bits). None of that belongs to the frame and none of it shows up in a packet capture, but it occupies the link all the same. Without it a 10 Gbps port would fit 19.5 million 64-byte frames per second; with it, 14.88 million. RFC 2544, the standard method for benchmarking network devices, uses the same 64-bit preamble and 96-bit gap for its maximum frame rates.
Interface counters, flow exports and most graphs count the bytes of frames or packets, not the preamble and gap, and devices differ on whether the 4-byte FCS is included. A port that is full at line rate therefore graphs below its nominal speed, most visibly with small packets: at 64 bytes the extra 20 bytes are 23.8 % of the line. Use On the wire for port speeds and line rate, and Frame only when the bit rate comes from such counters.
Frame size, packet size and padding
The MTU limits the IP packet, 1,500 bytes on standard Ethernet. The frame wraps it in a 14-byte header (two MAC addresses and the EtherType) and a 4-byte frame check sequence, so a full packet is a 1,518-byte frame. An 802.1Q VLAN tag adds 4 more. A frame is never shorter than 64 bytes: anything with less than 46 bytes of payload is padded, which is why a 40-byte TCP SYN without options costs exactly as much as a 46-byte packet.
For a mix of sizes, enter the average frame size weighted by packet count: divide an interface's byte counter by its packet counter over the same interval, and add 4 if the counters leave out the FCS. This page quotes no internet-wide average: published mixes differ by network and by year, and your own counters describe your traffic.
| Frame | IP packet | What it is |
|---|---|---|
| 64 bytes | up to 46 bytes (padded) | The smallest Ethernet frame. A TCP SYN or ACK without options is a 40-byte IPv4 packet and is padded up to 64 bytes, as is any packet of 46 bytes or less. |
| 78 bytes | 60 bytes | A 60-byte IPv4 SYN carrying the usual MSS, SACK, timestamp and window-scale options. It is above the 46-byte minimum payload, so nothing is padded: 60 + 18 = 78 bytes. |
| 558 bytes | 540 bytes | A DNS message at the classic 512-byte UDP limit of RFC 1035, plus 8 bytes of UDP, 20 of IPv4 and 18 of Ethernet header and FCS. |
| 1,518 bytes | 1,500 bytes | A 1,500-byte IP packet, the standard Ethernet MTU, with its 14-byte header and 4-byte FCS: the largest untagged standard frame. |
| 9,018 bytes | 9,000 bytes | A 9,000-byte IP packet on a network configured for jumbo frames, plus 18 bytes of header and FCS. |
Why packet rate matters as much as bandwidth
Routers, firewalls and servers do a roughly fixed amount of work per packet: a route lookup, a rule match, an interrupt or a trip through the kernel. Their limits are therefore quoted in packets per second as well as bits per second. The same 10 Gbps is 812,743 packets per second at full-size frames and 14.88 million at the minimum, more than eighteen times the per-packet work, so a device sized for the first can be overwhelmed by the second while the link is far from full.
That is why capacity planning needs both numbers. Floods of minimum-size packets, such as a SYN flood, exhaust the per-packet budget of a server or firewall long before they fill its uplink; TCP vs UDP explains why the two protocols produce such different packet sizes, and Layer 3/4 vs Layer 7 how volumetric attacks differ from application-layer ones.
How the 95th percentile is calculated
The 95th percentile is the value that 95 % of the samples are at or below. Transit and colocation contracts often bill on it: the provider records the average rate every five minutes, sorts a month of samples, discards the top 5 % and bills the highest value left, commonly taking the higher of the inbound and outbound figures. A 30-day month has 8,640 five-minute samples, so the 432 highest go: about 36 hours of bursts that cost nothing. The calculator under the result uses exactly that method, with the cut rounded down; check your contract for the sampling interval and how directions are combined.
Bursts longer than 5 % of the month set the bill, and traffic counts whether anyone wanted it or not, including a flood that reaches a metered port. Filtering attack traffic upstream, as DDoS protection does, keeps it off that port in the first place.
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