Tools
Subnet Calculator
Explore IPv4 and IPv6 networks, prefixes, ranges and address space.
Input
/24 means 24 network bits and 8 host bits.
Quick examples
Results
192.168.1.0/24
255.255.255.0
Usable range
192.168.1.1 – 192.168.1.254
IPv6 does not use broadcast addressing. The last address in a prefix is simply the highest address, and it is usable.
Advanced / binary view
Tools
Uptime Calculator
Translate availability targets into real downtime — and vice versa.
Input
Enter an availability target such as 99%, 99.9%, 99.99% or 99.999%.
Quick presets
The month is the 365/12 average; the year is 365 days.
Result
Allowed downtime for 99.9% SLA
8h 45m 36s
per year
Per year
8h 45m 36s
Per month
43m 48s
Per week
10m 4.8s
Per day
1m 26.4s
Per hour
3.6s
Uptime visualization
Small gains in availability lead to dramatically less allowed downtime. Moving from 99.9% to 99.99% reduces allowed downtime by 90%.
Common SLA targets
99%
3d 15h 36m
99.9%
8h 45m 36s
99.99%
52m 33.6s
99.999%
5m 15.36s
Yearly allowed downtime, from the same maths as the calculator above.
Tools
Network & Host Bits
See how a prefix splits an address into network bits and host bits — and how many addresses that leaves.
Input
An address with its prefix, e.g. 10.4.5.65/26 or 10.4.5.65 255.255.255.192.
Quick examples
Results
10.4.4.32/27
27 network bits 5 host bits
Common bits: first 23, which is 10.4.4.0/23
Matching both: GE 26 LE 27
Address 1 · 10.4.4.33/27
Network address
10.4.4.32/27
Broadcast address
10.4.4.63
Subnet mask
255.255.255.224
Wildcard mask
0.0.0.31
Total addresses
32
Usable hosts
30
How the count works
- 32 − 27 = 5 host bits
- 2⁵ = 32 addresses
- 32 − 2 = 30 usable hosts (network and broadcast are reserved).
The split falls inside octet 4: 3 network bits and 5 host bits, so that octet's mask is 224.
Address 2 · 10.4.5.65/26
Network 10.4.5.64/26 · 26 network bits · 6 host bits
Network 1 over network 2