API Bandwidth

Free API Bandwidth calculator with clear step-by-step results.

About API Bandwidth

Converts an API's request rate and payload sizes into the bandwidth and monthly egress volume it will actually consume. Both directions of the exchange are counted, header and TLS framing are added as an overhead percentage, and a peak-to-average factor gives the figure you size the link or the rate limit against.

Formulas

Average throughput

Mbps = RPS x (request KB + response KB) x (1 + overhead) x 8 / 1000

Monthly egress

TB/month = KB per second x 86,400 x 30.4 / 10^9

Worked example

With the default values below, API Bandwidth returns Average bandwidth of 31.050. Change any input above and every figure here is recalculated in your browser.

Inputs used

Average requests per secondminimum 0: 250
Average response payloadminimum 0 KB: 12 KB
Average request payloadminimum 0 KB: 1.5 KB
Header and TLS overheadaccepts 0–100 %: 15 %
Peak-to-average factoraccepts 1–20 x: 2.5 x

Results

Average bandwidth: 31.050 Mbps
Bandwidth to provision for peak: 77.625 Mbps
Data transferred per day: 335.340 GB
Data transferred per month: 10.1943 TB

Step by step

1Values used
2Average throughput
3Monthly egress
4Average bandwidth= 31.050 Mbps
5Bandwidth to provision for peak= 77.625 Mbps
6Data transferred per day= 335.340 GB
7Data transferred per month= 10.1943 TB

Assumptions and limits

The result is derived only from the 5 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 4 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 add an overhead percentage?

JSON payload size ignores HTTP headers, cookies, TLS record framing and TCP/IP headers. On small responses that overhead can exceed 30%; on large ones it is closer to 2%.

Is 1 GB taken as 1000 MB or 1024 MB?

Decimal - 1 GB = 10^6 KB. Cloud providers bill egress in decimal units, so this matches an invoice rather than a disk-usage tool.