HTTP Payload Size Calculator
Break an HTTP response into payload and protocol overhead.
About HTTP Payload Size Calculator
The bytes on the wire exceed the response body because headers and protocol framing ride along. For small responses the overhead can exceed the payload itself. This is why batching many tiny API calls into one request reduces total transfer far more than the payload arithmetic suggests.
Formula
HTTP Payload Size
Transfer = (compressed body + headers) × (1 + framing overhead)
- framing overhead
- TCP, TLS and HTTP/2 framing bytes on the wire
- payload efficiency
- Share of transferred bytes that carry actual content
Worked example
With the default values below, HTTP Payload Size Calculator returns Total Transfer Size of 15,517. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Response body sizeminimum 0 bytes
- 48,000 bytes
- Response header sizeminimum 0 bytes
- 520 bytes
- Body compression savingaccepts 0–100 %
- 70 %
- TCP and TLS framing overheadaccepts 0–50 %
- 4 %
Results
- Total Transfer Size
- 15,517 bytes
- Compressed Body Size
- 14,400 bytes
- Total Transfer Size
- 15.153 KB
- Non-Payload Overhead
- 1,117 bytes
- Payload Efficiency
- 92.803%
Step by step
- 1Values used
- 2HTTP Payload Size
- 3Total Transfer Size= 15,517 bytes
- 4Compressed Body Size= 14,400 bytes
- 5Total Transfer Size= 15.153 KB
- 6Non-Payload Overhead= 1,117 bytes
- 7Payload Efficiency= 92.803
Assumptions and limits
- The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 3 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
How is HTTP Payload Size calculated?
Transfer = (compressed body + headers) × (1 + framing overhead) The bytes on the wire exceed the response body because headers and protocol framing ride along. For small responses the overhead can exceed the payload itself.
Why does HTTP Payload Size matter?
This is why batching many tiny API calls into one request reduces total transfer far more than the payload arithmetic suggests.
What values do I need to enter?
This calculator takes 4 inputs: Response body size, Response header size, Body compression saving, TCP and TLS framing overhead. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.