You have 100 devices, each on a 10GB/month plan. Month-end: 30 used only 3GB, 20 maxed out 10GB, the other 50 averaged 4GB. Result: you paid for 1000GB but actually used ~450GB. The wasted 550GB is exactly what a data pool fixes.
How a data pool is actually billed
- Instead of per-SIM monthly plans, you buy one 'pool' (e.g. 600GB/month).
- All 100 SIMs share from this pool — whoever uses more or less is fine; you're billed on total actual usage.
- Unused pool isn't refunded, but you only pay extra if you exceed it — so sizing the pool right is the key.
The math with 100 SIMs
- Separate plans: 100 x 10GB = 1000GB capacity, 450GB used, pay 100% (55% wasted).
- Data pool: size a 600GB pool from the 450GB actual plus headroom; utilization jumps from 45% to near 100%.
- Same actual usage, the bill usually drops ~30% (depending on carrier unit price and headroom).
A data pool isn't universal
- Too few SIMs (<20) isn't worth it — management cost outweighs the gain.
- If usage is perfectly even and everyone maxes out, the pool has no advantage.
- A SIM with sudden spikes (e.g. temporary HD livestream backhaul) drains the pool instantly — keep separate headroom.
A data pool doesn't cut unit price — it cuts the half you'd never use. More SIMs, more uneven usage, more you save.