SMS Capacity
Calculate SMS throughput capacity for a messaging gateway or SMPP connection.
About SMS Capacity
SMS throughput on a signaling channel is bounded by dividing the available bandwidth by the total size of each message, which includes both the SMS payload itself (up to 140 bytes/1120 bits for a single-segment message) and the signaling protocol overhead needed to route and deliver it (SS7/MAP headers for network-to-network delivery, or SMPP PDU overhead for application-to-SMSC connections). This models a dedicated signaling link; in practice SMS delivery also depends on SMSC processing capacity and downstream mobile network paging/delivery success rates.
Formula
SMS throughput
sms_per_sec = bandwidth_bps / (sms_size_bits + overhead_bits)
Worked example
With the default values below, SMS Capacity returns Max SMS Throughput of 45.71. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Available Signaling Bandwidthminimum 1 bps
- 64,000 bps
- SMS Payload Sizeminimum 1 bits
- 1,120 bits
- Protocol Overhead per Messageminimum 0 bits
- 280 bits
Results
- Max SMS Throughput
- 45.71 msg/sec
- Max SMS Throughput
- 164,571 msg/hr
- Total Bits per Message (payload + overhead)
- 1,400 bits
Step by step
- 1Values used
- 2SMS throughput
- 3Max SMS Throughput= 45.71 msg/sec
- 4Max SMS Throughput= 164,571 msg/hr
- 5Total Bits per Message (payload + overhead)= 1,400 bits
Assumptions and limits
- The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax or compounding frequency into account.
- Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
Why is the standard SMS payload 140 bytes?
The original GSM SMS standard reserved a 140-byte (1120-bit) payload within a signaling message, which encodes to 160 characters using 7-bit GSM encoding, 140 characters using 8-bit encoding, or 70 characters using 16-bit UCS-2 encoding (needed for non-Latin scripts like Arabic, Chinese, or emoji) — longer messages are split into multiple linked segments, each consuming this same per-segment capacity.
What's the difference between SS7/MAP overhead and SMPP overhead?
SS7/MAP overhead applies to signaling between mobile network elements (MSC to SMSC, inter-carrier delivery) and is fairly fixed by the protocol standard. SMPP overhead applies to the connection between an application/aggregator and an SMSC (Short Message Service Center) and can vary based on optional TLV parameters used — both add meaningfully to the raw 1120-bit payload size when calculating real-world throughput.
Is signaling bandwidth usually the real bottleneck for SMS throughput?
Not always — modern SS7/SIGTRAN links and SMPP connections often have far more raw bandwidth than SMS traffic needs; the practical bottleneck is more often SMSC processing capacity (store-and-forward queuing, retry logic), per-connection throughput limits imposed by carriers/aggregators, or downstream mobile network congestion during high-volume campaigns.