Radio Duty Cycle Calculator

Tune radio airtime, reporting interval, channels, and device count to see compliance and capacity pressure

animation
networking
radio
duty-cycle
lpwan
lorawan
compliance
intermediate
A guided duty-cycle workbench for understanding radio airtime limits, required off-time, collision pressure, and battery trade-offs in unlicensed IoT networks.
Animation Radio Timing Compliance

Radio Duty Cycle Calculator

Change airtime, reporting interval, region, channel count, and fleet size. Watch one radio cycle update so duty cycle, required off-time, collision pressure, and battery impact stay connected.

0.019%Transmitter duty cycle
1.0%Selected rule
CompliantCompliance status
3.8 yearsEstimated battery life

Goal

See why a short radio burst can require a much longer quiet period in shared spectrum.

Try First

Select EU 868 1%, then increase airtime until the compliance gauge turns orange or red.

Watch

The TX slice, off-time, hourly budget, collision pressure, and diagnosis change together.

Why It Matters

Duty-cycle limits protect fair channel access, but they also shape latency, capacity, and battery life.

Scenario

Choose a starting device profile.

Regional Rule

Select the regulatory teaching model.

Playback

Radio Timing

Fleet Load

A reporting cycle starts with a radio transmission. Duty cycle compares that transmitter airtime with the full repeat interval.
Stay below limit.Expected behavior
56 ms every 5 min.Observed timing
Large safety margin.Working diagnosis

One Reporting Cycle

The TX slice is enlarged for teaching visibility. The numeric readouts carry the exact calculation.

Current duty: 0.019% Limit: 1.0%

Calculation Detail

The selected device is well below the current duty-cycle rule.

Hourly TX Budget

A 1% rule allows 36 s of TX per hour.

0.67 s used

Network Pressure

Unslotted ALOHA collision risk is a rough channel-load teaching estimate.

0.3% risk

Energy Estimate

Battery life uses average current across TX, RX, and sleep time.

3.8 years
Beginner Ramp

Duty cycle asks: out of a repeated time window, how much time is the transmitter actually on? A 1% limit means at most 1 second of TX in every 100 seconds.

Formula Reference
  • Duty cycle = TX airtime / report interval x 100%.
  • Required interval = TX airtime x 100 / limit percent.
  • Required off-time = required interval - TX airtime.
Regulatory Caution

This is a teaching calculator. Real products must check the exact regional band, sub-band, power, channel plan, listen-before-talk rules, dwell-time rules, and certification requirements.

EU 868 MHz

Many EU 868 MHz sub-bands use duty-cycle limits such as 0.1%, 1%, or 10%. LoRaWAN designs must account for the sub-band used by the channel plan, not only the number of channels shown in a gateway UI.

US 915 MHz

US 902-928 MHz operation is not usually managed by a simple 1% duty-cycle cap. Designs often need to satisfy frequency-hopping, dwell-time, digital-modulation, or power-density requirements instead.

Capacity Reality

The collision estimate uses a rough unslotted ALOHA model. Real capacity depends on spreading factors, channels, capture effect, gateway sensitivity, interference, payload size, acknowledgments, and retransmissions.

Practice 1

Use EU 868 1%. Set airtime to 1300 ms. What is the maximum number of messages per hour before the rule is exceeded?

Practice 2

Keep the same device count but double the channel count. What changes in collision pressure, and what does not change for one device's duty cycle?

Practice 3

Select US 915 MHz. Why does the diagnosis talk about dwell time instead of a simple duty-cycle percentage limit?

Related Study

LoRaWAN Spreading FactorExplore why spreading factor changes airtime and capacity. Protocol Overhead CalculatorConnect payload and headers to total bytes on the radio. RF Path Loss CalculatorCheck whether a lower data rate is needed for the link budget. Battery Life CalculatorExtend the energy estimate into a wider device power budget.