Technology & IT Calculators — United States
Capacity, bandwidth, storage and security arithmetic. These are definitions and physical limits, so the answers are the same wherever you are.
Networking & bandwidth
Data Transfer Time Calculator
How long a download, upload or backup will take at a given speed — and why it is always slower than the eight-times-smaller number you expected.
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Bandwidth Calculator
How much bandwidth a group of simultaneous users, video streams or calls actually needs — with headroom, so the connection does not saturate at the busiest moment.
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IP Subnet Calculator
Turn an IPv4 address and CIDR prefix into the subnet mask, network and broadcast addresses, the usable host range and how many hosts fit — with the private-range and wildcard details.
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Network Latency Calculator
The fastest a round trip can possibly be over a given distance — the physics floor no upgrade can beat — plus the realistic figure once routing and equipment are counted.
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Bandwidth Requirement Calculator
The bandwidth a site or office needs — from concurrent users, per-user demand, a peak factor and the headroom a link needs to stay responsive.
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Subnet Calculator
What a CIDR prefix gives you — usable hosts, network and broadcast addresses, the mask, and how many subnets a split produces.
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IP Address Count Calculator
How many addresses a CIDR prefix or an address range contains, and how many prefixes it takes to cover a given host count.
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Storage & data
Video Bitrate Calculator
The bitrate a video needs at a given resolution and frame rate, the file size that produces, and how long it will take to upload.
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RAID Capacity Calculator
How much usable space a RAID array gives you, how many disks can fail before you lose data, and what proportion of your disks are spent on redundancy.
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Database Growth Calculator
How large a database will grow given how many rows arrive each day and how big each one is — with indexes, overhead and the date it outgrows the disk.
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Aspect Ratio Calculator
Work out the missing dimension that keeps an image or video at the same shape — and name the ratio.
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Image Resize Calculator
Scale an image by a percentage or to a target size, and estimate the file size that results.
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Word Counter
Count words, characters, sentences and paragraphs — with reading and speaking time.
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Log Storage Calculator
How much storage a log retention policy needs — events per second, event size, compression and how long you keep them.
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Compression Ratio Calculator
Compression ratio, space saved and the throughput trade — including whether compressing before sending actually makes a transfer faster.
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Servers & reliability
Uptime & SLA Calculator
How much downtime each uptime percentage actually permits — per year, month, week and day — and what a chain of dependent services adds up to.
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Server Capacity Calculator
How many servers a given request rate needs — from peak traffic, how long each request takes and how much headroom you keep — including the spares to survive a failure.
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Concurrent Users Calculator
Turn daily visitors into the concurrent users a system actually has to hold at once — the number that decides how much capacity you need.
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Container Resources Calculator
Total CPU and memory a set of container replicas requests, how many nodes that needs, and what is left over once the system reserves its share.
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API Rate Limit Calculator
Whether your expected API traffic fits inside a rate limit — with the headroom left, the burst you can absorb, and how long a backlog takes to drain.
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Cloud Cost Calculator
A monthly cloud bill from its parts — compute hours, storage, egress and requests — and what a one-year commitment saves against on-demand.
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Server Load Calculator
How many servers a request load needs — from requests per second, response time and the concurrency each server can hold.
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Page Load Budget Calculator
Whether a page fits its load-time target — bytes over the connection, plus round trips, against the budget you set.
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Cache Hit Ratio Calculator
What a cache is actually buying — hit ratio, the effective average latency, and how much load it keeps off the origin.
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Compute Time Estimator
How long a computational job takes from the operations it needs and the hardware you have — devices, their peak rate, and the utilization you actually achieve — with the devices needed to hit a deadline and the cost at an hourly rate.
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Amdahl's Law Calculator
The speedup a parallel program gets from more processors when part of it must run serially — Amdahl's law — with the ceiling that serial fraction imposes, the efficiency per processor, and Gustafson's scaled alternative.
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Delivery Pipeline Flow Calculator
How long work takes to get through a delivery pipeline from how much is in progress and how fast it finishes — Little's law — and how much work in progress a target cycle time allows.
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VM Consolidation Calculator
How many physical hosts a set of virtual machines needs — from their vCPU and memory, the host's cores and RAM, the overcommit ratios you allow and the headroom you keep — with the binding constraint and the consolidation ratio.
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Error Budget Burn Rate Calculator
From a service-level objective and the error rate you are seeing, how fast the error budget is burning, how long until it is gone, and whether the budget consumed so far is ahead of or behind the calendar.
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Reserved Instance Break-Even Calculator
Whether committing to a reserved or savings-plan rate beats paying on demand, given how many hours a month you actually expect to run — the break-even utilization, the saving or loss over the term, and the months of unused commitment that would wipe it out.
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Software Licence Break-Even Calculator
Whether buying a perpetual licence with annual maintenance beats subscribing, over the years you expect to use the software — the year the two cross, the totals at your horizon, and the subscription price at which they tie.
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Security
Password Strength Calculator
How strong a password really is — its entropy in bits, the number of guesses needed, and how long that takes an attacker at realistic cracking speeds.
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Password Generator
Generate a strong random password or a memorable passphrase, with its entropy shown — reproducible from a seed, so you can regenerate the same one.
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Encryption Key Space Calculator
How many keys a given key length allows, and how long brute force would take — the arithmetic behind why 128-bit encryption is considered safe and 56-bit is not.
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Password Entropy Calculator
How much entropy a password has, and how long it survives at a stated guess rate — the honest arithmetic, not a strength meter.
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About these calculators
These calculators use decimal (SI) units throughout — 1 MB is 1,000,000 bytes and 1 Mbps is 1,000,000 bits per second, the convention used by storage vendors, network equipment and internet providers. Where an operating system reports binary units (1 MiB = 1,048,576 bytes) the difference is shown, because it is the usual reason a "1 TB" disk appears as 931 GB. Sizing results are arithmetic, not a capacity plan: real systems need headroom for peaks, failures and growth.