Allocate 802.1Q VLAN IDs across sites in aligned blocks and check the plan fits the 4094 usable IDs.
Rounding each site's allocation up to a power of two keeps VLAN ranges aligned, so a site's VLANs can be summarised in a trunk allowed-list or matched by a single mask instead of an arbitrary range. The planner then checks the total against the 4094 IDs 802.1Q actually gives you. VLAN IDs are a 12-bit field with no way to extend it, so a numbering scheme that is not aligned and bounded from day one turns into a renumbering project the first time you add a site.
VLAN ID
Each site gets the next power of two above its VLAN count so blocks stay bit-aligned; total = sites × block size, against the 4094 usable IDs.
Each site gets the next power of two above its VLAN count so blocks stay bit-aligned; total = sites × block size, against the 4094 usable IDs. Rounding each site's allocation up to a power of two keeps VLAN ranges aligned, so a site's VLANs can be summarised in a trunk allowed-list or matched by a single mask instead of an arbitrary range. The planner then checks the total against the 4094 IDs 802.1Q actually gives you.
VLAN IDs are a 12-bit field with no way to extend it, so a numbering scheme that is not aligned and bounded from day one turns into a renumbering project the first time you add a site.
This calculator takes 4 inputs: Sites to number, VLANs needed per site, IDs reserved for infrastructure, First allocatable VLAN ID. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.
You move the scaling boundary above 802.1Q: QinQ (802.1ad) gives a second 12-bit tag, and VXLAN's 24-bit VNI gives roughly 16 million segments. Both keep VLAN IDs local to a switch or site rather than globally unique.