IT Calculators
Conversions, network, storage, performance and developer tools.
Conversions and formats
ASCII / Unicode
Character code point (decimal, hex).
Use calculator →Base64 size
Base64 size overhead (~33%) — bytes ↔ string length.
Use calculator →Binary / Hex / Decimal
Number converter: binary, octal, hex, decimal.
Use calculator →Checksum
Simple checksum (mod 256/65536) — demo only, not a cryptographic hash.
Use calculator →Cron frequency
Cron expression (5 fields): human-readable description, runs in 24h/7 days, and upcoming fire times.
Use calculator →Duration
Time in seconds from notation like 1h 30m 45s.
Use calculator →Hash collisions
Estimated hash collision probability for n items and a b-bit hash using the birthday-bound approximation.
Use calculator →HEX ↔ RGB Color Converter
Bidirectional HEX ↔ RGB converter with color preview and CSS snippets.
Use calculator →Memory units
Convert KB, MB, GB, TB, KiB, MiB.
Use calculator →PX ↔ REM Converter
Convert px to rem and rem to px for any root font size. CSS examples, common UI values, px vs rem vs em.
Use calculator →Timezone converter
Convert between IANA time zones: enter a date and wall-clock time in the source zone; see the same instant in the target zone, optional extra zones, and UTC. DST is handled by your browser (Intl).
Use calculator →Unix timestamp
Unix timestamp ↔ date: seconds or milliseconds, UTC ISO, local time — with a copyable summary.
Use calculator →URL encode
URL encoding and decoding (percent-encoding).
Use calculator →Network
DHCP range
Number of host addresses in the DHCP pool for a given CIDR mask (/8\u2013/32). Network and broadcast addresses are excluded (minus 2).
Use calculator →DNS TTL
DNS record TTL in seconds.
Use calculator →IP Subnet / CIDR Calculator
Calculate subnet mask, network, broadcast, and host range for IPv4 CIDR.
Use calculator →IPv6 shorthand
Short IPv6 notation.
Use calculator →Latency vs distance
Minimum RTT for distance (fibre).
Use calculator →MTU and IP fragmentation
Number of IP fragments for a given MTU.
Use calculator →Storage and performance
Autoscaling (POD)
Min–max interpolation: estimated pods at a scale level (%).
Use calculator →Backup window
Time needed for backup at given throughput.
Use calculator →Bandwidth cost
Data transfer (egress) cost.
Use calculator →Bundle size
Rough minify / gzip / Brotli sizes from JS source size.
Use calculator →Cache hit ratio
Cache hit ratio and miss rate from hit and miss counts, plus the effect on backend load.
Use calculator →Cloud storage cost
Estimated monthly storage cost (GB).
Use calculator →Compression ratio
Compression level (size before/after).
Use calculator →Data transfer time
Realistic data transfer time from data size, link speed, and an efficiency percentage.
Use calculator →Database connections
Recommended database connection pool size from CPU cores and instance count, compared against max_connections.
Use calculator →File download time
File download time from file size and link speed, converting between binary and decimal units.
Use calculator →IOPS
Estimated IOPS and throughput (MB/s, KB/s) from latency and block size, with optional parallelism.
Use calculator →JSON size
Heuristic JSON payload size (chars × encoding model + overhead).
Use calculator →JWT token
Estimated JWT token size (Base64).
Use calculator →Log storage
Estimate disk space for logs: size per entry × number of entries × period. Consider rotation (e.g. logrotate) and compression (gzip).
Use calculator →PC power supply
Estimated power supply requirement (W).
Use calculator →Percentiles
Interpretation of latency percentiles.
Use calculator →Queue depth
Queue depth and latency.
Use calculator →RAID capacity
Usable and raw capacity for RAID 0, 1, 5, 6, 10, 15, 50, 60 from disk count and size.
Use calculator →Replication lag
Replication delay.
Use calculator →Resolution and PPI
Screen PPI/DPI and pixel size.
Use calculator →Storage cost
Monthly cloud disk cost.
Use calculator →Throughput (MB/s)
MB/s for 4K/64K block size.
Use calculator →Uptime and downtime
Convert uptime percentage (e.g. 99.9% \u2014 "three nines") to allowable downtime in minutes per year and per month. Useful for SLAs and availability targets.
Use calculator →Other
API rate limit
An API rate limit (requests per min, sec, or hour) converted into RPS, RPM, and minimum request interval.
Use calculator →Break-even: cloud vs on-premise
Cost comparison over time: cloud vs on-premise.
Use calculator →Cost per request
Cost of a single API request based on the price per million requests and your chosen volume.
Use calculator →Days until SSL expiry
Days and hours until SSL/TLS certificate expiry — status, warning threshold, and renewal window.
Use calculator →Deploy frequency
Deploys per day/week from interval.
Use calculator →Error budget
Availability SLO converted into allowed downtime in minutes per year and over a chosen period.
Use calculator →MTTR
MTTR and MTBF from repair time and failure count, plus estimated system availability as a percentage.
Use calculator →Password entropy
Password entropy in bits from length and character set size — an estimate of brute-force resistance.
Use calculator →Retry backoff
Delays between retries.
Use calculator →SSL certificate validity
SSL/TLS certificate validity window (notBefore → notAfter) in days, months, and years — with CA/Browser Forum lifetime context.
Use calculator →