# Days Browse 18 online Days tools for working with day-based data in your browser. Text inputs are not stored, and uploaded files are deleted after 6 hours. > Canonical page: https://elysiatools.com/en/tags/days ## Overview Use the Days tools collection to process, convert, validate, and manage day-related data through a browser interface without installing software. Processing runs on Elysia Tools servers. ## Frequently asked questions ### What can I do with Days tools? You can use 18 tools to process, convert, validate, and manage day-related data through the browser. ### Do I need to install software? No. The tools are available through the browser interface, with processing handled on Elysia Tools servers. ### How is my data handled? Text inputs are not stored. Uploaded files are automatically deleted after 6 hours. ## Tools - [A/B Test Significance Calculator](https://elysiatools.com/en/tools/ab-test-significance-calculator): Compute conversion-rate or mean differences, 95%/99% confidence intervals, two-sided p-values (Z-test for proportions, Welch t for continuous metrics), lift, sample size for 80%/90% power, recommended experiment days, plus sequential-testing and Bonferroni multiple-comparison warnings. - [Age Calculator](https://elysiatools.com/en/tools/age-calculator): Calculate age from birth date in years, months, days, and total time units - [Biorhythm Curve Plotter](https://elysiatools.com/en/tools/biorhythm-curve-plotter): Plot the classic 23-day physical, 28-day emotional, and 33-day intellectual biorhythm sine curves around any target date. See today's cycle states, mark zero-crossing "critical days", and read a daily value table with a combined total — enter your date of birth and a target date. - [Business Day Calculator](https://elysiatools.com/en/tools/business-day-calculator): Calculate business days excluding weekends - [Date Adder](https://elysiatools.com/en/tools/date-adder): Add or subtract time periods from a date (years, months, days, hours, minutes, seconds) - [Date Difference Calculator](https://elysiatools.com/en/tools/date-difference): Calculate the difference between two dates in various time units - [Days to Hours](https://elysiatools.com/en/tools/days-to-hours): Convert days to hours with configurable decimal precision - [Days to Months](https://elysiatools.com/en/tools/days-to-months): Convert whole days to exact calendar months from a specified start year and month - [Days to Weeks](https://elysiatools.com/en/tools/days-to-weeks): Convert days to weeks with configurable decimal precision - [Days to Years](https://elysiatools.com/en/tools/days-to-years): Convert whole days to exact calendar years from a specified start year - [Env File Secret Rotation Planner](https://elysiatools.com/en/tools/env-file-secret-rotation-planner): Paste a .env file and get a staged secret-rotation plan. Detects database URLs, API keys, auth tokens, private keys, cloud credentials, payment keys and encryption secrets, scores each by exposure and age, and schedules them across a 4-week rotation timeline with a dual-key checklist and a generated .env.example. Optional last-rotated dates and a configurable cadence (30/90/180/365 days) drive compliance scoring. - [Hours to Days](https://elysiatools.com/en/tools/hours-to-days): Convert hours to days with configurable decimal precision - [ISO 8601 Duration Builder](https://elysiatools.com/en/tools/iso-8601-duration-builder): Convert between natural-language durations and ISO 8601 durations (PnYnMnDTnHnMnS) in both directions with validation of edge cases - [Months to Days](https://elysiatools.com/en/tools/months-to-days): Convert whole calendar months to exact days from a specified start year and month - [Time Unit Converter](https://elysiatools.com/en/tools/time-converter): Convert between different time units (seconds, minutes, hours, days, weeks, etc.) - [Weeks to Days](https://elysiatools.com/en/tools/weeks-to-days): Convert weeks to days with configurable decimal precision - [Working Days Calculator](https://elysiatools.com/en/tools/working-days-calculator): Calculate working days between two dates, excluding weekends and holidays - [Years to Days](https://elysiatools.com/en/tools/years-to-days): Convert whole calendar years to exact days from a specified start year ## Related content - [Conversion](https://elysiatools.com/en/tags/conversion): Browse 369 online conversion tools for transforming data and files between supported formats. Use them in your browser with secure server-side processing. - [Math](https://elysiatools.com/en/tags/math): Browse 502 online math tools for working with math operations, data, and files in your browser. Text inputs are not stored, and uploaded files are deleted after 6 hours. - [Leap Year](https://elysiatools.com/en/tags/leap-year): Explore 3 online leap year tools in your browser for common leap year-related tasks, with processing handled securely on Elysia Tools servers. - [API](https://elysiatools.com/en/tags/api): Browse 35 online API tools for processing, converting, validating, and managing API data in your browser. - [Chart](https://elysiatools.com/en/tags/chart): Browse 53 online chart tools for processing, converting, validating, and managing chart files and data in your browser. - [Confidence Interval](https://elysiatools.com/en/tags/confidence-interval): Browse 9 online confidence interval tools for working with statistical interval calculations in your browser. Text inputs are not stored, and uploaded files are deleted after 6 hours.