Tool
LoRaWAN airtime calculator
Don’t waste your airtime. Use the fastest data rate you can: a shorter time on air means a longer battery life, less gateway utilisation and more messages within the duty cycle and the Fair Use Policy.
Time on air
61.7 ms
DR5 · SF7 · 125 kHz · 23 bytes on air
Fits: 232 of 242 bytes left at DR5.
- Fair Use Policy
- 486 / day
- Duty cycle
- 6.2 s
- Symbols
- 48 + 12.25 preamble
- Bit rate
- 5,469 bit/s
30 s of uplink airtime per day ≈ one uplink every 2 min 58 s
Minimum time between transmissions on one 1% sub-band (max 583 per hour)
1.024 ms per symbol
Nominal, before LoRaWAN overhead
The default channels sit in a 1% duty-cycle sub-band; the RX2 downlink channel (869.525 MHz) allows 10%.
All EU868 uplink data rates
10 bytes of payload. Select a row to inspect it.
| Data rate | Modulation | Time on air | Max payload | Fair use / day | Duty-cycle gap |
|---|---|---|---|---|---|
| SF12 · 125 kHz | 51 B | 20 | 2 min 28 s | ||
| SF11 · 125 kHz | 51 B | 36 | 1 min 22 s | ||
| SF10 · 125 kHz | 51 B | 80 | 37 s | ||
| SF9 · 125 kHz | 115 B | 145 | 21 s | ||
| SF8 · 125 kHz | 242 B | 265 | 11 s | ||
| SF7 · 125 kHz | 242 B | 486 | 6.2 s | ||
| SF7 · 250 kHz | 242 B | 972 | 3.1 s | ||
| FSK · 50 kbps | 242 B | 5,514 | 0.5 s | ||
| LR-FHSS · 137 kHz · CR 1/3 | 50 B | 14 | 3 min 23 s | ||
| LR-FHSS · 137 kHz · CR 2/3 | 115 B | 25 | 1 min 58 s | ||
| LR-FHSS · 336 kHz · CR 1/3 | 50 B | 14 | 3 min 23 s | ||
| LR-FHSS · 336 kHz · CR 2/3 | 115 B | 25 | 1 min 58 s |
How this is calculated
Time on air
The same formulas The Things Stack uses to schedule traffic: the Semtech LoRa design guide for LoRa (8-symbol preamble, explicit header, coding rate 4/5, low data rate optimisation for SF11 and SF12 at 125 kHz), plus the FSK and LR-FHSS frame formats. Uplinks include the 16-bit payload CRC; downlinks don’t carry one.
Payload limits
Maximum sizes come from the LoRaWAN Regional Parameters (RP002-1.0.4). Every frame adds 13 bytes on air — MAC header, device address, frame control and counter, port and the 4-byte message integrity code — plus any MAC commands in FOpts. See regional parameters and spreading factors.
Duty cycle and fair use
Where a duty cycle applies (1% on the EU868 default channels), a device must stay silent for 99× its time on air before transmitting again on that sub-band. On The Things Network, the Fair Use Policy adds 30 seconds of uplink airtime and 10 downlinks per device per day. Read more about the duty cycle.