Networking planner

DHCP Scope Planner

Turn a subnet into a practical DHCP scope plan with gateway, reserved addresses, and lease capacity.

Step 1

Enter network values

Use the example or enter your own subnet, plan, MAC, or port value.

Results update locally in your browser.

Plan gateway, reserved/static addresses, DHCP pool range, and estimated lease capacity for an IPv4 subnet.

Use verified network plans before changing production routing, ACLs, or firewall rules.
Planning workspace

DHCP scope insights

Capacity view for gateway, static reserves, dynamic pool, and safe lease headroom.

89%
DHCP pool share

225 DHCP addresses from 254 usable hosts.

83%
Recommended active leases

187 suggested active leases after buffer · High — growth could exhaust capacity.

Monitor lease growth

The scope has workable capacity, but active leases should be monitored because the target uses 74% of usable host space.
Next: Create exclusions/reservations first, then watch lease utilization during rollout.

Copy DHCP review memo

Copies locally from this browser session only; CalcShelf does not save the value.

Print worksheet

Prints this local browser view only; CalcShelf does not save scope values.

CSV / print export

Generated locally in this browser only. No plan values are stored or sent.

Address allocation

Gateway/static reserve vs DHCP pool inside the usable subnet.

Gateway + static reserveDHCP pool

Gateway

192.168.20.1

Static reserve

192.168.20.2 – 192.168.20.29

DHCP pool

192.168.20.30 – 192.168.20.254

DNS / NTP / option reminders

  • Set DNS servers, search/domain suffix, and NTP/time sources before production cutover.
  • Voice networks may need DHCP option 66/150 or vendor-specific options; PXE may need boot options.
  • Document lease duration, reservations, exclusions, and relay/helper addresses per VLAN.

Scope setup checklist

  • Exclude the gateway and static/infrastructure reserve range before enabling the DHCP pool.
  • Document DNS, NTP, domain suffix, relay/helper, and any voice/PXE/vendor options with the scope.
  • Set an alert or review point before active leases exceed the recommended capacity.
  • Keep static reservations documented so the dynamic pool does not drift into reserved space.

Planning notes

Use this as a worksheet and sanity check, not an automatic production configuration. Confirm VLAN IDs, routed interfaces, DHCP reservations, firewall rules, switch trunks, cloud ranges, and documentation standards before deploying changes.

Use it well

Get a better answer from the DHCP Scope Planner

  1. Start with the example values to see how the tool behaves.
  2. Swap in your own numbers, even if they are rough first-pass estimates.
  3. Change one input at a time so you can see what actually moves the result.

What the result means

The result turns network notation into something easier to read: ranges, host counts, masks, wildcard masks, ports, or planning blocks.

How to use it

Use the output to plan or double-check, then compare it with the real network before changing a route, VLAN, DHCP scope, firewall rule, or ACL.

What can change it

A valid network number can still be wrong for your environment if it overlaps, conflicts with routing, exposes traffic, or breaks change-control rules.

Good for

Reserve infrastructure and static addresses.

Check next

Compare your result with VLAN Planner, Network Planner, CIDR Subnet Calculator when you want more context.

Best habit

Run a conservative case and an optimistic case. The gap between them is often more useful than a single answer.

Common uses

  • Reserve infrastructure and static addresses.
  • Choose a DHCP start/end range.
  • Keep headroom in a lease pool.

Common questions

Is the DHCP Scope Planner private?

Yes. CalcShelf calculators run without an account, do not save calculator entries, and do not put raw inputs into shareable URLs or analytics events.

How accurate is the DHCP Scope Planner?

It follows common IPv4, CIDR, mask, range, and port conventions. Production networks still need live-config, routing, ACL, overlap, and change-control review.

What should I check after using the DHCP Scope Planner?

Verify live allocations, overlaps, gateway conventions, routes, ACL/firewall order, documentation, and rollback plan before production changes.

Which calculator should I try next?

Use the related calculators below to cross-check the same decision from another angle before you act.

Method behind the estimate

Networking tools use IPv4, CIDR, subnet mask, wildcard mask, range, VLAN, DHCP, and port-reference rules for planning and sanity checks.

Why the detail matters

Before changing production routing, firewall, VLAN, DHCP, or address plans, verify against the actual network, documentation, and change-control process.

Privacy guardrail

Your calculator values are for you. CalcShelf does not require an account, save calculator entries, put your numbers into shareable URLs, or use raw inputs as analytics events.

Copy or print safely

Use any copy, print, or worksheet controls as local handoff tools for your own notes, supplier calls, lender questions, or implementation checklist. They are there to help you explain the result to a human.

Before acting

Treat the result as a decision draft, not a verdict. Recheck the source numbers, run a downside case, and verify the real-world rule, quote, label, or spec that controls the final answer.

Last reviewed: May 11, 2026. See methodology and editorial policy for formulas, assumptions, rounding, review approach, and limitations. For network changes, verify against live configuration, vendor docs, and change-control requirements.