Packets Per Second Calculator
Inputs
| Link rate | 1 Gbps |
|---|---|
| Packet size | 1,500 B |
| Framing overhead | 0 B |
Packets Per Second Calculator
Work out how many packets per second a link can carry from its bit rate, the packet size, and any per-packet framing overhead. Shows why small packets cap a fast link long before its headline bit rate is reached.
Inputs
Link and Packet Details
Results
Enter a value to see results.
Packets Per Second
Bits Per Packet
Packets Per Second
Packets per second (pps) is the rate at which a link or device handles individual packets, as opposed to the raw number of bits it moves. It is the metric that decides whether a switch, router, or firewall keeps up under load, because network hardware does a fixed amount of work for every packet no matter how large or small that packet is. Sizing for pps — not just bits per second — is what keeps voice traffic, gaming, and packet floods from overwhelming a device whose headline bit rate looks more than adequate.
The formula
b=(P+F)×8 pps=bR=(P+F)×8Rwhere is the link rate in bits per second, is the packet size in bytes, is any per-packet framing overhead in bytes, and is the total on-the-wire size of one packet in bits. The factor of 8 converts the per-packet byte count into bits so it can be divided into the bit-rate figure.
Worked example. A 1 Gbps link carrying full-size 1500-byte packets with no extra framing overhead:
b=(1500+0)×8=12000 bits pps=120001000000000≈83333 packets/sSo a gigabit link tops out near 83,000 large packets each second. Halve the packet size to 750 bytes and the same link must forward roughly twice as many packets — about 166,000 per second — for the same bit rate.
Why packet size dominates
Because pps is the link rate divided by the per-packet bit count, it scales inversely with packet size. The table below shows the maximum frame rate of a 1 Gbps link at common payload sizes, ignoring framing overhead:
| Packet size | Bits per packet | Packets per second |
|---|---|---|
| 64 B | 512 | ~1,953,000 |
| 128 B | 1,024 | ~977,000 |
| 512 B | 4,096 | ~244,000 |
| 1500 B | 12,000 | ~83,000 |
| 9000 B (jumbo) | 72,000 | ~13,900 |
Moving from 1500-byte to 64-byte packets multiplies the packet rate by more than 20 while the bit rate stays the same. Each of those packets still needs a route lookup, an access-control check, and a counter update, so a device's pps capacity — not its Gbps rating — is what gives way first under a flood of tiny packets.
Framing overhead
The packet size alone undercounts what actually occupies the wire. On Ethernet, every frame is wrapped with extra bytes that still consume bit rate:
- Preamble and start delimiter — 8 bytes that let receivers synchronise.
- Ethernet header — 14 bytes of source and destination MAC plus the type field.
- Frame check sequence — 4 bytes of error-detecting CRC.
- Inter-frame gap — a mandatory 12-byte idle period between frames.
That adds about 38 bytes to every packet. Including it lowers the calculated packets per second slightly and matches the worst-case frame rate that interface vendors publish. For a 64-byte payload the overhead is proportionally large; for a 1500-byte payload it shaves only a couple of percent off the rate. Use the Ethernet quick pick to add the 38-byte allowance, or leave the overhead at zero to count payload only.
Line rate versus packets per second
Line rate is the physical bit rate of the link, such as 1 Gbps or 10 Gbps. Packets per second is how many discrete packets fit into that bit rate at a given size. A device can sustain line rate for large packets yet still drop small ones once its pps ceiling is reached, which is why datasheets quote both a Gbps figure and a separate pps (often written in millions, as Mpps) measured with minimum-size packets. When you compare hardware for latency-sensitive or attack-prone workloads, the small-packet pps number is the one that matters.
Related calculators
To see how header sizes shape the usable payload of each packet, use the MTU to MSS Calculator calculator. To estimate the data rate a TCP flow can actually achieve over a lossy path, use the TCP Throughput Calculator calculator. To convert a bit rate between bps, Mbps, Gbps, and bytes per second, use the Throughput (bps) Converter calculator.
Frequently Asked Questions (FAQ)
What does packets per second mean?
Packets per second (pps) is the rate at which a device forwards individual packets, regardless of how large each one is. Network hardware does a fixed amount of work per packet — look up a destination, apply rules, update counters — so pps, not raw bit rate, is often the real limit. A switch rated for 1.5 million pps can be saturated by small packets while its bit-rate capacity sits half-empty.
Why do small packets reduce throughput?
Every packet carries the same per-packet cost in hardware, and small packets spread a fixed bit rate across many more of them. A 1 Gbps link carries about 83,000 full 1500-byte packets per second, but roughly 1.49 million 64-byte packets per second. The smaller packets demand almost 18 times the forwarding work for the same number of bits, which is why DDoS floods and VoIP traffic stress devices far more than bulk file transfers.
What is the difference between line rate and packets per second?
Line rate is the raw bit rate of the physical link, such as 1 Gbps. Packets per second is how many discrete packets fit into that bit rate at a given size. A device that handles line rate for large packets can still drop small ones if its pps capacity is exceeded, so vendors quote both a Gbps figure and a separate pps (or Mpps) figure for worst-case small-packet performance.
Should I include Ethernet framing overhead?
For an accurate on-the-wire count, yes. Beyond the packet payload, each Ethernet frame adds a 7-byte preamble, a 1-byte start delimiter, 14 bytes of header, a 4-byte frame check sequence, and a 12-byte inter-frame gap — about 38 bytes in total.
Adding this overhead lowers the packets-per-second figure slightly and matches the maximum frame rate that interface vendors publish. Set the overhead to zero if you only want the rate based on payload size.