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Web Proxy Capacity Calculator

Size a secure web gateway cluster: appliances required with N+1 sparing, users per node and access-log storage.

About Web Proxy Capacity Calculator

Divide the peak request rate by the rated per-appliance rate and round up for the active node count, then add spares so a failure or maintenance window does not push the survivors past capacity. Access logs are sized independently: every request writes a line, and at proxy volumes that dominates your SIEM ingest bill. Web proxy log volume is routinely the largest single feed into a SIEM, so discovering the storage cost after deployment turns a security control into a budget problem.

Formula

Web Proxy Capacity

active appliances = ceil(peak rps ÷ rated rps); total = active + spares; log storage = requests per day × bytes per request × retention days.

rated rps
Vendor-rated request rate per appliance with your policy enabled
spares
Extra nodes so a failure does not reduce capacity below peak

Worked example

With the default values below, Web Proxy Capacity Calculator returns Appliances Required of 2. Change any input above and every figure here is recalculated in your browser.

Inputs used

Users to serveaccepts 1–5,000,000 users
20,000 users
Requests per user per houraccepts 1–100,000 req/h
300 req/h
Peak-to-average factoraccepts 1–10 ×
2.2 ×
Rated requests per second per applianceaccepts 10–5,000,000 req/s
6,000 req/s
Spare appliances for redundancyaccepts 0–20 appliances
1 appliances
Access log bytes per requestaccepts 50–8,192 bytes
350 bytes
Log retentionaccepts 1–3,650 days
90 days

Results

Appliances Required
2
Active Appliances
1
Peak Request Rate
3,666.7 req/s
Utilisation of Active Nodes
61.1%
Users per Appliance
10,000
Access Log Storage
4.13 TiB

Step by step

  1. 1Values used
  2. 2Web Proxy Capacity
  3. 3Appliances Required= 2
  4. 4Active Appliances= 1
  5. 5Peak Request Rate= 3,666.7 req/s
  6. 6Utilisation of Active Nodes= 61.1
  7. 7Users per Appliance= 10,000
  8. 8Access Log Storage= 4,536,000,000,000.00

Assumptions and limits

  • The result is derived only from the 7 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 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

How is Web Proxy Capacity calculated?

active appliances = ceil(peak rps ÷ rated rps); total = active + spares; log storage = requests per day × bytes per request × retention days. Divide the peak request rate by the rated per-appliance rate and round up for the active node count, then add spares so a failure or maintenance window does not push the survivors past capacity. Access logs are sized independently: every request writes a line, and at proxy volumes that dominates your SIEM ingest bill.

Why does Web Proxy Capacity matter?

Web proxy log volume is routinely the largest single feed into a SIEM, so discovering the storage cost after deployment turns a security control into a budget problem.

What values do I need to enter?

This calculator takes 7 inputs: Users to serve, Requests per user per hour, Peak-to-average factor, Rated requests per second per appliance, Spare appliances for redundancy, Access log bytes per request, Log retention. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

Should the rated rps come from the datasheet?

Only as a starting point. Datasheet figures assume minimal policy: no TLS interception, no sandboxing, no data-loss inspection and a small category database. With full TLS interception enabled, expect a third or less of the rated figure, so validate against a proof of concept with your real policy.

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