Subnet Merger
Paste two or more IPv4 networks. The result is the smallest subnet that contains all of them, aligned to a real prefix boundary.
What gets covered
Each input is normalized to its network and broadcast. The cover is the longest prefix whose block holds the lowest network and the highest broadcast in that set.
Overlapping and nested networks are counted once. A /24 inside a /16 does not widen the /16.
Questions
No. The smallest subnet that contains every input can also contain addresses you did not list. The result says when that happens, and how many extra addresses are inside the cover.
Yes. 192.168.1.0/25 and 192.168.1.128/25 together are exactly 192.168.1.0/24. A gap, such as 10.0.0.0/24 and 10.0.2.0/24, needs a wider cover.
Sources
Reviewed 8 October 2026. The methodology page records what these labels do not cover.
Related tools
- Subnet SplitterDivide a network into equal, non-overlapping subnets.
- Subnet CalculatorNetwork, broadcast, mask, and usable hosts for an IPv4 address and prefix.
- CIDR CalculatorStart from CIDR notation and see the exact block it names.
- IP Range CalculatorInclusive block bounds, then the usable host range.
