INDEPENDENT PERSPECTIVESMonday, October 05, 2026A little context goes a long way ↗
Martin Lumen

Technology. Money.
The human condition.

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The practical corner

Useful tools.
Clear answers.

Small calculations for dates, work, planning, and money. No account required.

01
Date & time

Days between dates

Count elapsed calendar days between two dates.

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02
Date & time

Business-day planner

Count weekdays and exclude your own holiday dates.

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03
Work

Shift end time

Find an end time from working hours and an unpaid break.

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04
Planning

Visual date planner

See your date range on a month-by-month calendar.

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05
Bitcoin

Bitcoin & satoshi converter

Convert BTC, satoshis, and a USD amount using your chosen price.

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06
Money

Recurring investment growth

Explore a hypothetical fixed-return contribution scenario.

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Date and work tools developed from the Day Delta Tools project. Calculations run in your browser.