Free Online Network Tools
Inspect IP address ranges, prepare network lists and calculate link capacity with free online network tools. All tools use supplied data locally.
Choose the right tool
Use exact CIDR aggregation to preserve address coverage, a covering supernet when extra addresses are acceptable, and the overlap checker before subtracting ranges. Throughput tools use supplied measurements or ideal bounds. No tool performs live network scans or remote DNS lookups.
Available tools
- IPv4 CIDR Aggregator
Use this online ipv4 cidr aggregator with pasted values. Exact union only; never fills gaps between ranges.
- IPv4 Range to CIDR Blocks
Use this online ipv4 range to cidr blocks with pasted values. Returns the smallest exact CIDR cover of the supplied inclusive address interval.
- Equal Size IPv4 Subnet Splitter
Use this online equal size ipv4 subnet splitter with pasted values. Normalizes host bits before splitting; output capped at 4096 subnets.
- Smallest Covering IPv4 Supernet
Use this online smallest covering ipv4 supernet with pasted values. Covering block can include addresses absent from the input; use CIDR Aggregator for an exact union.
- IPv4 CIDR Wildcard Mask Calculator
Use this online ipv4 cidr wildcard mask calculator with pasted values. Only contiguous CIDR masks; wildcard is an ACL bit mask, not a host count.
- Subnet Mask to CIDR Prefix Checker
Use this online subnet mask to cidr prefix checker with pasted values. Rejects noncontiguous masks; supports /0 and /32.
- CIDR Prefix to Subnet Mask
Use this online cidr prefix to subnet mask with pasted values. IPv4 only; /0 is 0.0.0.0 and /32 is 255.255.255.255.
- Numeric IPv4 Address Sorter
Use this online numeric ipv4 address sorter with pasted values. Retains duplicates; lexicographic string sorting would produce a different order.
- IPv4 Address List Deduplicator
Use this online ipv4 address list deduplicator with pasted values. IPv4 address-aware list cleanup with strict dotted decimal validation.
- IPv4 Address Scope Classifier
Use this online ipv4 address scope classifier with pasted values. Common-scope classifier, not an exhaustive routability, geolocation or live IANA lookup.
- IPv4 Reverse DNS Name Builder
Use this online ipv4 reverse dns name builder with pasted values. Builds the PTR query name only; performs no DNS lookup.
- IPv6 Prefix Range Calculator
Use this online ipv6 prefix range calculator with pasted values. Exact BigInt address count; IPv6 has no broadcast address.
- IPv6 CIDR Membership Checker
Use this online ipv6 cidr membership checker with pasted values. Hex IPv6 only; embedded dotted IPv4 and zone identifiers unsupported.
- IPv6 Reverse DNS Name Builder
Use this online ipv6 reverse dns name builder with pasted values. Constructs a query name locally without a PTR lookup.
- IPv6 Subnet Count Calculator
Use this online ipv6 subnet count calculator with pasted values. Exact decimal count as a string; does not enumerate huge address spaces.
- Mixed IPv4 and IPv6 List Validator
Use this online mixed ipv4 and ipv6 list validator with pasted values. Reports invalid entries without discarding the valid rows; no zones or embedded IPv4 in IPv6.
- MAC to Modified EUI-64 Interface ID
Use this online mac to modified eui-64 interface id with pasted values. Computes a modified EUI-64 interface ID only; modern IPv6 interfaces may use privacy or stable opaque identifiers.
- IPv4 Multicast to Ethernet MAC
Use this online ipv4 multicast to ethernet mac with pasted values. Mapping is many-to-one; different multicast IPv4 groups can share the same Ethernet MAC.
- IPv4 CIDR Overlap Checker
Use this online ipv4 cidr overlap checker with pasted values. Normalizes both networks and returns the exact overlap as CIDR blocks.
- Subtract IPv4 CIDR from Network
Use this online subtract ipv4 cidr from network with pasted values. Subtracts one contiguous CIDR block from another; does not alter device configuration.
- Bandwidth Delay Product Calculator
Use this online bandwidth delay product calculator with pasted values. Decimal Mbit/s and round-trip time; this is data in flight, not a speed test.
- TCP Window Limited Throughput Calculator
Use this online tcp window limited throughput calculator with pasted values. Single flow ideal window bound; congestion, loss and link capacity may lower throughput.
- Packet Payload Efficiency Calculator
Use this online packet payload efficiency calculator with pasted values. Supply all headers, trailers and other overhead you want included.
- TCP MSS from IP MTU Calculator
Use this online tcp mss from ip mtu calculator with pasted values. Arithmetic payload limit; user supplies actual header sizes and path MTU, not an automatically negotiated MSS.
- UDP Payload from IP MTU Calculator
Use this online udp payload from ip mtu calculator with pasted values. No fragmentation, tunneling or extra application headers included.
- Packet Rate from Link Speed Calculator
Use this online packet rate from link speed calculator with pasted values. Include preamble, gaps, framing and encapsulation in wire_bytes as appropriate.
- Packet Serialization Delay Calculator
Use this online packet serialization delay calculator with pasted values. Transmission time onto the link; excludes propagation, queuing and processing.
- Cable Propagation Delay Calculator
Use this online cable propagation delay calculator with pasted values. Physical path length rather than straight-line endpoint distance; excludes equipment delay.
- Network Link Utilization Calculator
Use this online network link utilization calculator with pasted values. Counter scope and direction must match the supplied capacity; no live traffic collection.
- Packet Loss Percentage Calculator
Use this online packet loss percentage calculator with pasted values. Compare matching measurement intervals; duplicates or counter resets must be resolved first.
- Independent Packet Loss Event Probability
Use this online independent packet loss event probability with pasted values. Independent identical Bernoulli loss assumption; burst loss violates this model.
- Measured Application Goodput Calculator
Use this online measured application goodput calculator with pasted values. Decimal MB and Mbit; count unique delivered payload, excluding retransmitted bytes.
- VoIP Bandwidth per Stream Calculator
Use this online voip bandwidth per stream calculator with pasted values. Single one-way stream with continuous audio; add link overhead yourself and account separately for silence suppression.
- DHCP Lease Renewal Time Calculator
Use this online dhcp lease renewal time calculator with pasted values. Default fractions follow the usual DHCPv4 defaults; explicit server values may differ.
- DNS TTL Expiry Offset Calculator
Use this online dns ttl expiry offset calculator with pasted values. Local arithmetic only; resolvers can refresh, cap TTL or serve stale data.
- Network Port Range Expander
Use this online network port range expander with pasted values. Parses local text only; does not scan ports or identify services.
- Network Port List Range Compressor
Use this online network port list range compressor with pasted values. Accepts numeric JSON ports; does not validate firewall syntax for a specific platform.
- IPv4 Address and Wildcard Match Checker
Use this online ipv4 address and wildcard match checker with pasted values. Wildcard one bits are ignored; supports noncontiguous wildcard masks.
- IPv4 Longest Prefix Route Matcher
Use this online ipv4 longest prefix route matcher with pasted values. Only prefix selection; ignores metrics, policy routing, next-hop reachability and equal-cost paths.
- 802.1Q VLAN ID List Validator
Use this online 802.1q vlan id list validator with pasted values. Does not infer device-specific reserved VLANs or configure switches.
- DNS Hostname Label Validator
Use this online dns hostname label validator with pasted values. Hostname syntax only, not every DNS owner name; underscores and raw Unicode fail.
- Unicode Domain to ASCII IDNA Converter
Use this online unicode domain to ascii idna converter with pasted values. Uses browser IDNA behavior; not a domain ownership, availability or security check.
- IPv4 Mapped IPv6 Address Builder
Use this online ipv4 mapped ipv6 address builder with pasted values. Creates the IPv4-mapped representation used by APIs; does not imply native IPv6 connectivity.
- IPv6 Multicast to Ethernet MAC
Use this online ipv6 multicast to ethernet mac with pasted values. Many-to-one Ethernet mapping; does not subscribe to a multicast group.
- Internet Ones Complement Checksum Calculator
Use this online internet ones complement checksum calculator with pasted values. Zero the checksum field first when computing a packet checksum.
- TCP Sequence Number Wrap Calculator
Use this online tcp sequence number wrap calculator with pasted values. Count SYN and FIN as one sequence number yourself; this is modular arithmetic, not a TCP stream analyzer.
- RTT Sample Statistics Calculator
Use this online rtt sample statistics calculator with pasted values. Uses pasted samples only; does not send ping packets.
- Successive RTT Variation Calculator
Use this online successive rtt variation calculator with pasted values. A simple RTT-variation measure, not the RFC 3550 RTP interarrival jitter estimator.
- RF Link Received Power Budget Calculator
Use this online rf link received power budget calculator with pasted values. Scalar budget using supplied gains and losses; no terrain, interference or legal transmit-power assessment.
- Free Space Radio Path Loss Calculator
Use this online free space radio path loss calculator with pasted values. Far-field line-of-sight free space; ignores obstacles, reflection, atmosphere and antenna gains.