https://networkcalc.com/api/vlsm/{parent}
Allocates the requested subnets inside the parent network. Subnets are sorted largest first and placed end to end, each on a boundary aligned to its own size.
curl https://networkcalc.com/api/vlsm/192.168.1.0/24?hosts=Sales%3A60%2CEngineering%3A28%2CManagement%3A10%2CWAN%20A%3A2%2CWAN%20B%3A2
{
"status": "OK",
"meta": {},
"parent": {
"cidr": "192.168.1.0/24",
"network_address": "192.168.1.0",
"broadcast_address": "192.168.1.255",
"subnet_mask": "255.255.255.0",
"total_addresses": 256
},
"allocations": [
{
"order": 1,
"input_position": 1,
"name": "Sales",
"requested_hosts": 60,
"cidr": "192.168.1.0/26",
"network_address": "192.168.1.0",
"broadcast_address": "192.168.1.63",
"first_host": "192.168.1.1",
"last_host": "192.168.1.62",
"subnet_mask": "255.255.255.192",
"wildcard_mask": "0.0.0.63",
"prefix": 26,
"block_size": 64,
"usable_hosts": 62,
"spare_hosts": 2,
"offset": 0,
"reason": "60 hosts + 2 reserved (network and broadcast) = 62 addresses. The smallest block that holds that is a /26 (64 addresses, 62 usable), leaving 2 spare. It is placed at the start of the parent network."
},
{
"order": 2,
"input_position": 2,
"name": "Engineering",
"requested_hosts": 28,
"cidr": "192.168.1.64/27",
"network_address": "192.168.1.64",
"broadcast_address": "192.168.1.95",
"first_host": "192.168.1.65",
"last_host": "192.168.1.94",
"subnet_mask": "255.255.255.224",
"wildcard_mask": "0.0.0.31",
"prefix": 27,
"block_size": 32,
"usable_hosts": 30,
"spare_hosts": 2,
"offset": 64,
"reason": "28 hosts + 2 reserved (network and broadcast) = 30 addresses. The smallest block that holds that is a /27 (32 addresses, 30 usable), leaving 2 spare. It is placed at the next /27-aligned address after 192.168.1.0/26."
},
{
"order": 3,
"input_position": 3,
"name": "Management",
"requested_hosts": 10,
"cidr": "192.168.1.96/28",
"network_address": "192.168.1.96",
"broadcast_address": "192.168.1.111",
"first_host": "192.168.1.97",
"last_host": "192.168.1.110",
"subnet_mask": "255.255.255.240",
"wildcard_mask": "0.0.0.15",
"prefix": 28,
"block_size": 16,
"usable_hosts": 14,
"spare_hosts": 4,
"offset": 96,
"reason": "10 hosts + 2 reserved (network and broadcast) = 12 addresses. The smallest block that holds that is a /28 (16 addresses, 14 usable), leaving 4 spare. It is placed at the next /28-aligned address after 192.168.1.64/27."
},
{
"order": 4,
"input_position": 4,
"name": "WAN A",
"requested_hosts": 2,
"cidr": "192.168.1.112/30",
"network_address": "192.168.1.112",
"broadcast_address": "192.168.1.115",
"first_host": "192.168.1.113",
"last_host": "192.168.1.114",
"subnet_mask": "255.255.255.252",
"wildcard_mask": "0.0.0.3",
"prefix": 30,
"block_size": 4,
"usable_hosts": 2,
"spare_hosts": 0,
"offset": 112,
"reason": "2 hosts + 2 reserved (network and broadcast) = 4 addresses. The smallest block that holds that is a /30 (4 addresses, 2 usable), leaving 0 spare. It is placed at the next /30-aligned address after 192.168.1.96/28."
},
{
"order": 5,
"input_position": 5,
"name": "WAN B",
"requested_hosts": 2,
"cidr": "192.168.1.116/30",
"network_address": "192.168.1.116",
"broadcast_address": "192.168.1.119",
"first_host": "192.168.1.117",
"last_host": "192.168.1.118",
"subnet_mask": "255.255.255.252",
"wildcard_mask": "0.0.0.3",
"prefix": 30,
"block_size": 4,
"usable_hosts": 2,
"spare_hosts": 0,
"offset": 116,
"reason": "2 hosts + 2 reserved (network and broadcast) = 4 addresses. The smallest block that holds that is a /30 (4 addresses, 2 usable), leaving 0 spare. It is placed at the next /30-aligned address after 192.168.1.112/30."
}
],
"unallocated": [],
"free": {
"addresses": 136,
"ranges": [
{
"start": "192.168.1.120",
"end": "192.168.1.255",
"addresses": 136,
"cidrs": [
"192.168.1.120/29",
"192.168.1.128/25"
]
}
]
},
"summary": {
"parent_addresses": 256,
"allocated_addresses": 120,
"free_addresses": 136,
"allocated_percent": 46.9,
"free_percent": 53.1,
"requested_hosts": 102,
"usable_hosts_in_allocations": 110,
"spare_hosts_in_allocations": 8,
"subnets_requested": 5,
"subnets_allocated": 5
},
"map": {
"size": 256,
"segments": [
{
"name": "Sales",
"cidr": "192.168.1.0/26",
"offset": 0,
"size": 64
},
{
"name": "Engineering",
"cidr": "192.168.1.64/27",
"offset": 64,
"size": 32
},
{
"name": "Management",
"cidr": "192.168.1.96/28",
"offset": 96,
"size": 16
},
{
"name": "WAN A",
"cidr": "192.168.1.112/30",
"offset": 112,
"size": 4
},
{
"name": "WAN B",
"cidr": "192.168.1.116/30",
"offset": 116,
"size": 4
}
]
}
}Parameters
{parent}(Required) The IPv4 network to divide, in CIDR notation. Must be /30 or larger.
Example: https://networkcalc.com/api/vlsm/192.168.1.0/24
hosts(Required) A comma-separated list of the subnets to allocate, each as name:hosts or just hosts. Up to 64 subnets. Names are optional, up to 32 characters.
Example: https://networkcalc.com/api/vlsm/192.168.1.0/24?hosts=Sales:60,Engineering:28,Management:10
Response Format
Response Codes
200
OK - Success. Every requested subnet was allocated.400
NO_PARENT_SPECIFIED - The {parent} parameter was not specified.400
INVALID_PARENT - The parent is not a valid IPv4 CIDR block.400
PARENT_TOO_SMALL - The parent network must be /30 or larger.400
NO_REQUIREMENTS_SPECIFIED - The hosts parameter was not specified.400
INVALID_REQUIREMENT - One or more entries in hosts is not a whole number of hosts. The entries are listed in invalid.400
TOO_MANY_REQUIREMENTS - More than 64 subnets were requested.400
INSUFFICIENT_SPACE - The parent does not have room for every subnet. The response still includes the allocations that fit and the unallocated subnets that did not.