Home Features Pricing Network Map Monitoring

Diag Tools

HTTP Check Ping Test DNS Lookup SSL Certificate WHOIS Lookup Port Check IP Lookup Offline Tools My Check History

Advanced Tools Minimal interface

Home Features Pricing Network Map Monitoring

Diag Tools

Minimal interface

Home Diagnostic Tools Offline Tools IP & Subnet Subnet Mask ⇄ Prefix + Cheat-Sheet

Subnet Mask ⇄ Prefix + Cheat-Sheet

Convert a netmask to a CIDR prefix (and back), with the full /0–/32 reference table.

This interactive tool needs JavaScript enabled. For a static overview of Emercom's free network tools, see the tool guides.

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