Starlight Tools
Packets Per Second Calculator
Convert bandwidth and packet size into Ethernet packets per second (PPS or Mpps). Account for VLAN tags, minimum-frame padding, FCS, preamble, start-frame delimiter and inter-frame gap, or work backward from a target PPS.
Inputs
Results
Enter valid values to calculate packet rate.
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How to use the PPS calculator
- Enter nominal bandwidth: choose bps, Kbps, Mbps, Gbps or Tbps. Network-rate units are decimal.
- Identify your size: choose a complete Ethernet frame, an IP packet, or application payload so headers are not counted twice.
- Set encapsulation: add VLAN and protocol headers only when they are not already present in the entered size.
- Choose line accounting: include preamble/SFD and inter-frame gap for theoretical Ethernet line-rate PPS.
- Apply headroom: reduce usable link rate to model an operating limit, then compare PPS with device forwarding specifications.
Packets per second formulas
Wire bytes per packet: MAC frame bytes + selected preamble/SFD + selected IFG
PPS: (bandwidth in bits/s × usable fraction) ÷ (wire bytes × 8)
Required bandwidth: (target PPS × wire bytes × 8) ÷ usable fraction
Packet time: 1 ÷ PPS
Payload efficiency: useful entered bytes ÷ wire bytes × 100%
For IP-packet mode, the calculator adds a 14-byte Ethernet header, 4-byte FCS and selected VLAN tags, then pads the MAC frame to at least 64 bytes. Application mode also adds the selected IP and transport headers.
Common Ethernet PPS values at 100% of line rate
| MAC frame | Wire occupancy | 1 Gbps | 10 Gbps | 100 Gbps |
|---|---|---|---|---|
| 64 B minimum | 84 B | 1.488 Mpps | 14.881 Mpps | 148.810 Mpps |
| 128 B | 148 B | 844.595 kpps | 8.446 Mpps | 84.459 Mpps |
| 512 B | 532 B | 234.962 kpps | 2.350 Mpps | 23.496 Mpps |
| 1518 B standard | 1538 B | 81.274 kpps | 812.744 kpps | 8.127 Mpps |
| 1522 B VLAN | 1542 B | 81.064 kpps | 810.636 kpps | 8.106 Mpps |
| 9018 B jumbo | 9038 B | 13.831 kpps | 138.305 kpps | 1.383 Mpps |
Values include 8 bytes of preamble/SFD and the minimum 12-byte inter-frame gap. PPS is per direction.
What Ethernet overhead is included?
A basic Ethernet MAC frame runs from destination address through the frame check sequence (FCS). A standard untagged frame with a 1500-byte IP packet is 1518 bytes. For line-rate timing, Ethernet also transmits a 7-byte preamble, 1-byte start-frame delimiter and observes at least a 12-byte inter-frame gap.
VLAN tags increase a frame by 4 bytes when the same IP packet is carried. Very small payloads are padded so the basic MAC frame is at least 64 bytes. Jumbo-frame limits are vendor-specific, so enter the actual frame size rather than assuming that “9000 MTU” and “9000-byte frame” mean the same thing.
Standards and reference notes
- RFC 894 specifies a 46-byte minimum Ethernet data field and a 1500-byte maximum IP datagram for Ethernet encapsulation.
- RFC 3635 defines the standard MTU for Ethernet-like interfaces as 1500 octets.
- IEEE 802.3 task-force material summarizes the 7-byte preamble, 1-byte SFD, 64–1518-byte basic frame and minimum 12-byte inter-packet gap used here.
Packets per second FAQs
How many packets per second can 1 Gbps Ethernet carry?
About 1,488,095 minimum-size 64-byte frames per second, or about 81,274 standard 1518-byte frames per second, when the 20 bytes of preamble/SFD and inter-frame gap are included.
Why are 20 bytes added outside the Ethernet frame?
The physical link sends 8 bytes of preamble and start-frame delimiter, then leaves a minimum 12-byte inter-frame gap. They consume time even though they are not counted in the MAC frame size.
Does a VLAN tag change PPS?
Yes, when it increases the transmitted frame by 4 bytes. If your entered frame size already includes the tag, select Ethernet-frame mode and do not add it a second time.
Is the result bidirectional?
No. PPS is per direction. Full-duplex Ethernet provides the nominal line rate separately in each direction.
Does the calculator include PCS encoding and FEC?
No. It models MAC frames, preamble/SFD and inter-frame gap. Encoding, FEC and other PHY-specific overhead vary by Ethernet variant.
Will a firewall rated for this PPS always keep up?
No. Real capacity depends on packet-size mix, enabled services, flow churn, queues, bursts and vendor test conditions. Check tested throughput and PPS with the production feature set.
Is this calculator private?
Yes. Inputs are processed locally and are not sent to a calculation backend.
Planning limits
This is a deterministic Ethernet capacity estimate, not a device guarantee. Validate production designs against vendor data sheets, test methodology, packet-size distribution, feature configuration, oversubscription, burst behavior and measurements from the intended path.
Last reviewed: July 2026.