Quick answer
Packet loss = (sent − received) ÷ sent × 100. Sending 1,000 packets and receiving 985 is a loss of 1.5%.
Enter packets sent and received. The calculator returns the loss percentage.
Related tools: IP Subnet Calculator: IPv4 network, broadcast, mask and host range from an address and CIDR prefix. Download Time Calculator: Time to download a file at a given speed. Bandwidth Calculator: Bandwidth needed to move a file in a given time.
How to use the Packet Loss Calculator
- Enter packets sent (above 0).
- Enter packets received (0 or more).
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Packets sent | A number | > 0 |
| Packets received | A number | ≥ 0 |
Formula and method
Formula
loss = (sent − received) ÷ sent × 100
IEEE-754 double precision; shown to the decimals indicated.
Duplicates are not handled.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Packets sent = 1000; Packets received = 985.
| Result | Value |
|---|---|
| Packet loss | 1.5% |
Example 2
Inputs: Packets sent = 50; Packets received = 50.
| Result | Value |
|---|---|
| Packet loss | 0% |
Example 3
Inputs: Packets sent = 200; Packets received = 150.
| Result | Value |
|---|---|
| Packet loss | 25% |
The first line is the headline result (packet loss). IEEE-754 double precision; shown to the decimals indicated.
Why it matters
Even 1% loss hurts TCP throughput and makes voice and video choppy. Under 0.1% is considered healthy for most connections.
Rules
Received cannot exceed sent. Test over enough packets for the figure to be stable.
Reading packet loss
(1,000 − 985) ÷ 1,000 = 1.5% loss. The sample size matters: one lost packet in 100 and ten in 1,000 are both 1%, but the larger sample is more reliable.
Loss of even a few percent can break real-time voice and video and lowers throughput on TCP connections because lost data is resent. Zero loss does not prove a healthy link, since delay and jitter are separate measurements.
How the result changes with packets sent
Holding every other input at the first worked example, this table changes only packets sent. It shows how sensitive the answer is to that one value; each row was produced by running this calculator.
| Packets sent | Packet loss |
|---|---|
| 1000 | 1.5% |
| 2000 | 50.75% |
| 4000 | 75.375% |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Packets sent: entering "0" shows "Packets sent must be greater than 0." beside that field and no result.
- Packets received: entering "20" shows "Received packets cannot exceed sent packets." beside that field and no result.
Choosing between the Packet Loss Calculator and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [IP Subnet Calculator](/technology/ip-subnet-calculator/) | iPv4 address and cIDR prefix length | Network |
| [Download Time Calculator](/technology/download-time-calculator/) | file size, size unit and connection speed | Time |
| [Bandwidth Calculator](/technology/bandwidth-calculator/) | data size, size unit and time allowed | Bandwidth required |
| [Data Transfer Calculator](/technology/data-transfer-calculator/) | speed, speed unit and duration | Data transferred |
| [Latency to Distance Calculator](/technology/latency-to-distance-calculator/) | round-trip latency and signal speed as a fraction of c | Approximate distance |
Background: networking and display
Network speeds are quoted in bits per second and file sizes in bytes, and a byte is 8 bits, so a 100 Mbps link moves at most 12.5 megabytes per second; real throughput is usually below the advertised rate. Pixel density is the diagonal in pixels divided by the diagonal in inches: a 1920×1080 display of 24 inches is about 92 pixels per inch, and a 3840×2160 display of 27 inches about 163.
Assumptions and limitations
- Received cannot exceed sent
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for packets sent and packets received to confirm this.
Frequently asked questions
What loss is acceptable for VoIP?
For voice over IP, packet loss should stay under about 1%; above that, calls start to break up.
How do I measure it?
With ping or a traceroute tool.
What causes loss?
Congestion, faulty links or Wi-Fi interference.
How many packets should I send for a reliable measurement?
More is better. Hundreds or thousands give a steadier estimate than a handful, and loss can vary over time.
Does 0% packet loss mean the network is fine?
Not necessarily. Latency and jitter can still be poor even when no packets are lost.
What does the Packet Loss Calculator calculate?
Percentage of packets lost. It returns Packet loss.
What formula does the Packet Loss Calculator use?
loss = (sent − received) ÷ sent × 100. Duplicates are not handled.
What do I need to enter in the packet Loss Calculator?
You enter Packets sent and Packets received.
How is the result rounded or limited?
IEEE-754 double precision; shown to the decimals indicated. Received cannot exceed sent.
What is an example of a packet Loss result?
With packets sent 1000 and packets received 985, the packet loss is 1.5%.
Where does the method come from?
The method follows: RFC 2680, A One-way Packet Loss Metric for IPPM (IETF, 1999): packet loss as the fraction of packets not received.
Related calculators
- IP Subnet Calculator — IPv4 network, broadcast, mask and host range from an address and CIDR prefix.
- Download Time Calculator — Time to download a file at a given speed.
- Bandwidth Calculator — Bandwidth needed to move a file in a given time.
- Data Transfer Calculator — Amount of data moved at a speed over a time.
- Latency to Distance Calculator — Approximate one-way distance from round-trip latency.
- Network Throughput Calculator — Maximum TCP throughput from window size and round-trip time.
Sources
- RFC 2680, A One-way Packet Loss Metric for IPPM (IETF, 1999): packet loss as the fraction of packets not received
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.