Wireless packet airtime estimate calculator

Packet payload plus supplied fixed overhead; retries omitted.

rf-wireless-airtime.napkin / editable

SCENARIO COMPARISON

Compare the numbers.

This source describes an analytical model. Its quantities and checks are the view.

Scenario	airtimes	utilization
	0.001	0.1
	0.00084	0.084

All calculated quantities are listed with the inputs. Switch to Source to inspect the equations.

SCENARIOS / CALCULATED VALUESSAME SOURCE

Change an input to see the consequences.

channel utilization budget0.10 ✓ passes

BASELINE INPUTS

payloadBits800 overheadBits200 bitRate1000000 s^-1packetsPerSecond100 s^-1

CALCULATED

airtime0.001 s

utilization0.1

Edits change the baseline source.

THE SOURCE

Edits below update the same model.

# Wireless packet airtime estimate
# Scope: Packet payload plus supplied fixed overhead; retries omitted.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

payloadBits = 800
overheadBits = 200
bitRate = 1000000 s^-1
packetsPerSecond = 100 s^-1

airtime := (payloadBits+overheadBits)/bitRate [s]
utilization := airtime*packetsPerSecond

check channel utilization budget: utilization <= 0.2

scenario alternative: payloadBits = 640

Calculated from your source · not saved

Baseline · Baseline

channel utilization budget0.10 ✓ passes

alternative · alternative

channel utilization budget0.08 ✓ passes

Illustrative first-order example. Checks are editable requirements, not design standards. The broader topic may require additional equations, data, and validation.

Formula and units

This example uses the following equations. Input names and units match the editable source above.

airtime: airtime = (payloadBits+overheadBits)/bitRate [s]
utilization: utilization = airtime*packetsPerSecond

Original worked example

These are the baseline values in the downloadable source. Edits above let you test your own values.

Given

payload bits: 800
overhead bits: 200
bit rate: 1000000 s^-1
packets per second: 100 s^-1

Calculated

airtime: 0.001 s
utilization: 0.1

Assumptions and limits

Packet payload plus supplied fixed overhead; retries omitted.

The requirement checks use the limits written in this example. Passing a check does not establish that the model covers every load, material behavior, or operating condition in a real design.

Download this .napkin example ↓

Take it further with your agent

Napkin keeps the inputs, equations, checks and assumptions together in one study. Your agent sets it up; you change the numbers.

Try with Claude ↗

codex 'Use Napkin (https://napkin.engineering/mcp, or the local Napkin plugin) to build a study: Wireless packet airtime estimate. Inputs: modulation/rate; packet fields; overhead; retransmission assumption. Outputs: airtime; payload throughput; energy estimate. Model scope: Link and transmission models with declared propagation assumptions. Read napkin_capabilities and the current snapshot. Ask me for the values that matter, label assumptions with units, author .napkin source, validate it and apply it with napkin_source using the current revision, then open the study. Add checks for the limits I supply. Keep unsupported analyses explicit.'

Claude needs the Napkin connector; Codex needs the Napkin plugin. Set up your agent ↗

The broader study

The topic brief below describes the broader scope. The worked example above states the particular calculation it implements.

Inputs: modulation/rate, packet fields, overhead, retransmission assumption
Outputs: airtime, payload throughput, energy estimate
Modes: calculate, compare, sweep
Drawing: Link-budget and coverage plots

EXECUTABLE WORKED EXAMPLE · FIRST-ORDER MODEL · CHECK THE SCOPE & ASSUMPTIONS