Engineering calculators for network and IT teams
Free network, voice, Wi-Fi, power and CCTV calculators from Vajra Telecom engineers. These are the calculators our own engineers use when they size networks, voice trunks, Wi-Fi, PoE switches, UPS batteries, fibre links and CCTV storage.
Free network, voice, Wi-Fi, power and CCTV calculators from Vajra Telecom engineers.
These are the calculators our own engineers use when they size networks, voice trunks, Wi-Fi, PoE switches, UPS batteries, fibre links and CCTV storage. They are free, need no sign-up and run entirely in your browser, so nothing you type is sent to us.
Every tool shows its working and explains the assumptions behind the answer. When the numbers are close to a limit, or the design matters, talk to us and an engineer will check it with you.
Pick a tool
Subnet Calculator (IPv4 & IPv6)
Work out the network, broadcast, host range and mask of any IPv4 or IPv6 subnet.
Open toolVLSM Subnet Planner
Split one network into right-sized subnets for each department, VLAN or link.
Open toolBandwidth & Download Time Calculator
Find how long a file takes to transfer, or the link speed you need to move it in time.
Open toolVoIP / SIP Bandwidth Calculator
Calculate the bandwidth your SIP trunk or IP phones need per call and in total.
Open toolErlang B & E1/PRI Channel Calculator
Work out how many voice channels and E1 or T1 PRI lines you need from your busy-hour call volume.
Open toolWi-Fi Capacity Planner
Estimate how many access points you need for the number of users and devices on site.
Open toolPoE Power Budget Calculator
Check whether a PoE switch can power your cameras, access points and phones.
Open toolUPS Battery Runtime Calculator
Estimate how long your UPS batteries will keep network and server equipment running.
Open toolFibre Link Loss Budget Calculator
Calculate optical loss on a fibre link and check it against your SFP's power budget.
Open toolCCTV Storage Calculator
Work out NVR hard disk capacity for your cameras, resolution and retention period.
Open toolMAC Address Vendor Lookup
Find the manufacturer of a network device from its MAC address.
Open toolCommon questions
Are these tools free?
Yes. All the calculators are free to use, with no sign-up and no limits.
Is my data sent anywhere?
No. Every calculation runs in your browser. The MAC lookup downloads the public IEEE vendor list once and searches it on your device.
How accurate are the results?
They use the standard formulas engineers use for planning, and each page explains its assumptions. Real networks vary, so treat the results as a planning estimate and validate critical designs with a survey or test.
Can Vajra Telecom design this for us?
Yes. Each tool links to the matching service. Send us your numbers and an engineer will review the design with you.
