Subnet / CIDR Range Expander & Aggregator

Expand a range into individual IPs, or aggregate ranges into minimal CIDR blocks.

Mode

CIDR or IP range

256 total addresses

10.0.0.0
10.0.0.1
10.0.0.2
10.0.0.3
10.0.0.4
10.0.0.5
10.0.0.6
10.0.0.7
10.0.0.8
10.0.0.9
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10.0.0.11
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10.0.0.19
10.0.0.20
10.0.0.21
10.0.0.22
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10.0.0.24
10.0.0.25
10.0.0.26
10.0.0.27
10.0.0.28
10.0.0.29
10.0.0.30
10.0.0.31
10.0.0.32
10.0.0.33
10.0.0.34
10.0.0.35
10.0.0.36
10.0.0.37
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10.0.0.42
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10.0.0.46
10.0.0.47
10.0.0.48
10.0.0.49
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10.0.0.56
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10.0.0.58
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10.0.0.60
10.0.0.61
10.0.0.62
10.0.0.63
10.0.0.64
10.0.0.65
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10.0.0.67
10.0.0.68
10.0.0.69
10.0.0.70
10.0.0.71
10.0.0.72
10.0.0.73
10.0.0.74
10.0.0.75
10.0.0.76
10.0.0.77
10.0.0.78
10.0.0.79
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10.0.0.81
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10.0.0.83
10.0.0.84
10.0.0.85
10.0.0.86
10.0.0.87
10.0.0.88
10.0.0.89
10.0.0.90
10.0.0.91
10.0.0.92
10.0.0.93
10.0.0.94
10.0.0.95
10.0.0.96
10.0.0.97
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10.0.0.100
10.0.0.101
10.0.0.102
10.0.0.103
10.0.0.104
10.0.0.105
10.0.0.106
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10.0.0.132
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10.0.0.154
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10.0.0.158
10.0.0.159
10.0.0.160
10.0.0.161
10.0.0.162
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10.0.0.168
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10.0.0.171
10.0.0.172
10.0.0.173
10.0.0.174
10.0.0.175
10.0.0.176
10.0.0.177
10.0.0.178
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10.0.0.180
10.0.0.181
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10.0.0.183
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10.0.0.185
10.0.0.186
10.0.0.187
10.0.0.188
10.0.0.189
10.0.0.190
10.0.0.191
10.0.0.192
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10.0.0.194
10.0.0.195
10.0.0.196
10.0.0.197
10.0.0.198
10.0.0.199
10.0.0.200
10.0.0.201
10.0.0.202
10.0.0.203
10.0.0.204
10.0.0.205
10.0.0.206
10.0.0.207
10.0.0.208
10.0.0.209
10.0.0.210
10.0.0.211
10.0.0.212
10.0.0.213
10.0.0.214
10.0.0.215
10.0.0.216
10.0.0.217
10.0.0.218
10.0.0.219
10.0.0.220
10.0.0.221
10.0.0.222
10.0.0.223
10.0.0.224
10.0.0.225
10.0.0.226
10.0.0.227
10.0.0.228
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10.0.0.231
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10.0.0.250
10.0.0.251
10.0.0.252
10.0.0.253
10.0.0.254
10.0.0.255

What is this tool?

Expand mode lists every host IP in a single CIDR or IP range (capped at 4,096 addresses to keep the page responsive — larger ranges show a count plus first/last addresses instead). Aggregate mode takes multiple CIDRs, IP ranges, and/or bare IPs (auto-promoted to /32, so raw access logs or IP lists paste in directly), merges overlapping or adjacent ones, and summarizes the result into the minimal set of properly-aligned CIDR blocks — the standard greedy CIDR-summarization algorithm used by routers and firewall rule generators. Distinct from the IPv4 Subnet Calculator, which computes network/broadcast/host-range details for a single CIDR rather than expanding or merging ranges.

How to use it

Choose Expand or Aggregate.
Expand: enter one CIDR or IP range. Aggregate: enter multiple CIDRs/ranges/bare IPs, one per line.
Copy the resulting address list or minimal CIDR blocks.

What is this tool?

How to use it

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