ISP capacity planning
ISP Bandwidth Calculator
Estimate required upstream capacity from subscribers, average plan speed, oversubscription, and optional headroom.
Required capacity
5 Gbps1 : 10 oversubscriptionCapacity planning
How to estimate ISP bandwidth
Count active customers
Use the subscribers sharing the same aggregation, backhaul, or upstream capacity.
Set plan and contention
Enter the representative plan speed and the oversubscription ratio used in your network design.
Add operational headroom
Reserve capacity for traffic growth, failures, maintenance, and peak-hour variation.
Network context
What affects required ISP capacity
Busy-hour demand
Peak concurrent usage matters more than monthly averages when sizing links.
Subscriber mix
Residential, business, mobile, gaming, and video-heavy customers create different utilization patterns.
Resilience and growth
Redundant paths, forecast growth, bursts, and SLA commitments require additional headroom.
How is ISP bandwidth capacity calculated?
Multiply customers by average plan speed, then divide by the oversubscription ratio.
What does 1:10 oversubscription mean?
It means ten units of sold access speed share one unit of planned upstream capacity.
Is 5 Gbps enough for 1,000 customers on 50 Mbps plans?
It is the mathematical result at 1:10 oversubscription. Actual busy-hour measurements and headroom should confirm the design.