Chapter 9: Calculator

Interactive real-time calculators for SIEM sizing, storage planning, EPS capacity, alert triage, and ROI analysis

Accurate sizing and capacity planning are critical to a successful cybersecurity monitoring deployment. Under-sizing leads to event loss, alert delays, and system instability; over-sizing wastes budget that could be invested in additional detection capabilities. The following five interactive calculators provide real-time estimates for the key sizing parameters of a cybersecurity monitoring system, based on industry-standard formulas and empirical data from production deployments.

1 EPS Capacity & Collector Sizing Calculator

Estimate the required Events Per Second (EPS) throughput and number of log collectors based on your environment size and device inventory.

1100
5010,000
5500
050
1.5x5x
Estimated Peak EPS
12,500
events per second at peak load
Firewalls
4,000
Endpoints
3,500
Network
1,500
Cloud
1,000
2
Log Collectors Required
Medium
Deployment Tier
Formula: EPS = (Firewalls × 400) + (Endpoints × 7) + (Switches × 50) + (Cloud × 200). Peak EPS = Average EPS × Multiplier. Collectors = ceil(Peak EPS / 20,000).

2 Log Storage Sizing Calculator

Calculate the total storage capacity required for your SIEM based on daily log volume, retention period, and compression ratio.

10 GB10 TB
30d730d (2yr)
2:110:1
10%40%
Total Storage Required
6.4 TB
raw capacity with RAID & buffer
4.0 TB
Compressed Data
40 GB
Compressed/Day
5.3 TB
After RAID Overhead
6.4 TB
With Hot Spare
Storage Breakdown
Data
RAID
Spare
Formula: Compressed Daily = Daily Volume / Compression Ratio. Raw Storage = Compressed Daily × Retention Days. With RAID = Raw × RAID Factor. Final = With RAID × (1 + Spare%).

3 Alert Triage Workload & Analyst Staffing Calculator

Estimate the daily alert volume, analyst workload, and required SOC staffing based on your environment and tuning maturity.

505,000
20%95%
0%80%
5 min60 min
4 hrs8 hrs
Daily Actionable Alerts
90
alerts requiring analyst triage per day
Alert Funnel
Raw
500
After FP
150
Actionable
90
4
Analysts Required
22.5 hrs
Daily Triage Hours
Formula: After FP = Raw × (1 - FP%). Actionable = After FP × (1 - Correlation%). Daily Hours = Actionable × Triage Time / 60. Analysts = ceil(Daily Hours / Productive Hours).

4 Log Collection Network Bandwidth Calculator

Calculate the network bandwidth required for log forwarding from all sources to the log collector and SIEM platform.

100100,000
100B2,000B
1.5x5x
Required Bandwidth
27.6 Mbps
peak bandwidth for log collection
9.2 Mbps
Average Bandwidth
Recommended Link
9.2%
Avg Link Utilization
27.6%
Peak Link Utilization
Peak Link Utilization
27.6%
Formula: Avg Bandwidth (bps) = EPS × Event Size × 8 × Overhead Factor. Peak = Avg × Burst Multiplier. Recommended Link = next standard link speed above Peak × 2 for headroom.

5 Cybersecurity Monitoring ROI Calculator

Estimate the return on investment of your cybersecurity monitoring system based on breach cost reduction, MTTR improvement, and compliance savings.

$50K$5M
1%50%
$100K$50M
10%90%
$0$2M
3-Year Net ROI
+247%
return on investment over 3 years
$555K
Annual Benefit
10.8 mo
Payback Period
$1.67M
3-Year Benefit
$1.5M
3-Year Cost
3-Year Benefit Breakdown
Breach Reduction
Compliance
Formula: Annual Breach Savings = Breach Probability × Breach Cost × Breach Reduction. Annual Benefit = Breach Savings + Compliance Savings. ROI = (3-Year Benefit − 3-Year Cost) / 3-Year Cost × 100%.
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