Tech Calculators
Calculate IP subnets, CIDR notation, and bandwidth conversions with free online tech calculators. Essential networking tools for IT professionals and students.
About Tech Calculators
Our tech calculators provide essential networking and IT tools for professionals, students, and anyone working with computer networks and data transfer.
The IP Subnet Calculator is the go-to tool for network planning and administration. Enter any IP address with CIDR notation to instantly see the subnet mask, network address, broadcast address, usable host range, and total available addresses. It supports all IPv4 address classes and correctly identifies private address ranges.
The Bandwidth Calculator converts between all common data transfer rate units — from bits per second to gigabytes per second — and estimates download times for common file sizes. This is invaluable for comparing internet plans, planning data transfers, and understanding network capacity.
Both tools require zero plugins and work entirely in your browser. All calculations are performed client-side with no data sent to any server, making them safe for use with sensitive network information.
Frequently Asked Questions
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation uses a slash followed by a number (like /24) after an IP address to indicate the subnet mask length. The number represents how many bits are used for the network portion. For example, /24 means the first 24 bits identify the network, leaving 8 bits (256 addresses) for hosts.
What is the difference between Mbps and MBps?
Mbps (megabits per second) and MBps (megabytes per second) are different units. Since 1 byte = 8 bits, 100 Mbps equals 12.5 MBps. Internet speeds are typically advertised in Mbps, while file sizes are shown in MB or GB, which often causes confusion about actual download speeds.
How do I know if an IP address is private?
Private IP addresses fall within three reserved ranges: 10.0.0.0 to 10.255.255.255 (Class A), 172.16.0.0 to 172.31.255.255 (Class B), and 192.168.0.0 to 192.168.255.255 (Class C). These addresses are not routable on the public internet and are used for local networks.
What subnet should I use for my home network?
Most home networks use a /24 subnet (255.255.255.0), which provides 254 usable addresses — more than enough for typical home devices. Your router likely defaults to 192.168.1.0/24 or 192.168.0.0/24. For larger networks with many IoT devices, a /23 (510 hosts) may be more appropriate.
How long does it take to download 1 GB?
Download time depends entirely on your connection speed. At 100 Mbps, 1 GB takes about 80 seconds. At 25 Mbps, it takes about 5.3 minutes. At 1 Gbps fiber, it takes about 8 seconds. Our bandwidth calculator shows exact download times for various file sizes based on your specific speed.