Free online network tools
Ten instant network utilities that run entirely in your browser. Diagnose subnets, decode headers, look up ports — no signup, no upload.
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IP / CIDR Calculator
Calculate network address, broadcast, host range, and subnet mask from any CIDR notation.
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Subnet Calculator
Divide a network into equal subnets — enter a base CIDR and desired subnet count to get the full breakdown.
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MAC Vendor Lookup
Identify the hardware manufacturer behind any MAC address using the OUI prefix database.
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Ping Output Explainer
Paste ping command output and get a plain-English breakdown of RTT, TTL, packet loss, and what each value means.
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Traceroute Explainer
Paste traceroute output and decode every hop: latency, asterisks, firewalls, and routing anomalies explained.
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Port Number Lookup
Look up any TCP/UDP port number to see its standard service name, protocol, and common use cases.
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HTTP Headers Decoder
Paste raw HTTP request or response headers and get a parsed, human-readable table with field descriptions.
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SSL/TLS Grade Info
Understand SSL Labs grades (A+, A, B, C, D, F) and learn what TLS configuration choices affect your score.
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DNS Record Explainer
Select any DNS record type — A, AAAA, CNAME, MX, TXT, NS, SOA, CAA, PTR, SRV — and get a detailed explanation with examples.
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WHOIS Formatter
Paste raw WHOIS output and get a clean, structured table showing domain, registrar, dates, status, and name servers.
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Why use browser-based network tools?
Every tool here runs entirely inside your browser — no server round trips, no account needed, no data sent to a third party. Whether you are diagnosing a subnet, decoding HTTP headers, or looking up a port number, all processing happens locally and results are instant.
Choosing the right tool
Use the IP/CIDR Calculator when you have CIDR notation and need the network address, broadcast, and host range. Use the Subnet Calculator when you need to split a network into equal-sized subnets. For hardware identification, the MAC Vendor Lookup decodes the OUI prefix of any MAC address. To understand command output, use the Ping Explainer or Traceroute Explainer. For web debugging, the HTTP Headers Decoder and SSL/TLS Grade Info cover the most common questions.