Tool Guides
Follow worked examples for dates, pay, permissions, networks and local file tools. Processing runs in your browser; no account is required.
Dates and time
Calculate duration between dates and times
Measure an overnight interval or a span of months, compare total hours with calendar units, and check month ends and leap days.
Work hours and pay
Calculate timesheet hours with breaks
Follow a 37.5-hour week, convert minutes to decimal hours, and enter an overnight shift with the correct dates.
Convert salary to hourly pay
Compare annual, monthly and hourly gross pay using explicit paid hours and weeks, then check the effect of actual working hours.
Calculator guides
Read IP Subnets and CIDR
Follow IPv4 network and host-range examples, understand /31 and /32, compare IPv6 counts and split address space into bounded equal subnets.
Convert Unix Timestamps and Time Zones
Identify epoch units, preserve fractional and pre-epoch values, and resolve repeated or nonexistent clock times with an explicit IANA zone.
Count Days and Add Calendar Dates
Compare elapsed days with inclusive date counts, follow leap-year examples and add or subtract calendar days without daylight-saving errors.
Understand Linux File and Directory Permissions
Read octal and rwx modes, compare 600, 644 and 755, and understand directory search and special permission bits.
Calculate Download and Transfer Time
Work through file-size and speed examples, distinguish Mbps from MB/s and GB from GiB, and estimate transfers with an explicit efficiency assumption.
File workflows
Rename files from Excel or CSV
Prepare a two-column mapping, review proposed names, resolve conflicts and download renamed copies with a manifest.