Edge Location Planner

Work out how many edge locations a latency target needs, from the distance budget the speed of light allows.

About Edge Location Planner

Subtracting processing time from the latency target leaves a propagation budget, which converts directly into a maximum user-to-edge distance at 200,000 km/s. Because locations cover area rather than distance, mean distance falls with the square root of location count — so halving latency needs about four times the footprint, which is where the cost curve bites. This is the quantitative version of 'just add more PoPs': the squared relationship means the last 10 ms costs far more than the first 50 ms, and beyond a point buying more locations is worse value than cutting processing time or payload size.

Formula

Edge Location

distance budget: Furthest a user can be and still meet the latency target
route factor: How much longer the cable path is than the straight line
squared term: Halving mean distance needs roughly four times the locations

Worked example

With the default values below, Edge Location Planner returns Locations Needed of 15. Change any input above and every figure here is recalculated in your browser.

Inputs used

Locations todayaccepts 1–500 locations: 6 locations
Average user distance to the nearest locationaccepts 1–20,100 km: 1,800 km
Latency targetaccepts 1–5,000 ms: 25 ms
Edge processing time per requestaccepts 0–5,000 ms: 8 ms
Fibre path vs straight lineaccepts 1–3 ×: 1.4 ×
Spare locations for failureaccepts 0–50 locations: 1 locations
Monthly cost per locationaccepts 0–10,000,000 USD: 3,500 USD
Traffic servedaccepts 0.001–10,000,000 TB/month: 200 TB/month

Results

Locations Needed: 15 locations
Locations to Add: 9 locations
Round-Trip Time Today: 33.20 ms
Round-Trip Time After the Build: 25.00 ms
Distance Budget for the Target: 1,214 km
Monthly Cost of the New Locations: $31,500.00
Footprint Cost per TB Served: $262.5000

Step by step

1Values used
2Edge Location
3Locations Needed= 15 locations
4Locations to Add= 9 locations
5Round-Trip Time Today= 33.20 ms
6Round-Trip Time After the Build= 25.00 ms
7Distance Budget for the Target= 1,214 km
8Monthly Cost of the New Locations= 31,500.00

Assumptions and limits

The result is derived only from the 8 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

How is Edge Location calculated?

distance budget = (target RTT − processing) × 200,000 ÷ (2 × route factor), and because coverage grows with area, locations needed ≈ current locations × (current distance ÷ budget)², plus spares. Subtracting processing time from the latency target leaves a propagation budget, which converts directly into a maximum user-to-edge distance at 200,000 km/s. Because locations cover area rather than distance, mean distance falls with the square root of location count — so halving latency needs about four times the footprint, which is where the cost curve bites.

Why does Edge Location matter?

This is the quantitative version of 'just add more PoPs': the squared relationship means the last 10 ms costs far more than the first 50 ms, and beyond a point buying more locations is worse value than cutting processing time or payload size.

What values do I need to enter?

This calculator takes 8 inputs: Locations today, Average user distance to the nearest location, Latency target, Edge processing time per request, Fibre path vs straight line, Spare locations for failure, Monthly cost per location, Traffic served. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.