Pro Calculators and Guides
How to Estimate Your Due Date From Your Last Period or Conception Date
Work out your estimated due date and how many weeks pregnant you are, with trimester start dates. Learn the 280-day rule and its limits.
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Pro Calculators and Guides
Specialist calculators are only useful when you understand the rules behind the numbers. These guides explain what each professional calculator does, which inputs matter, how to read the result and where the official rules come from, covering payroll and tax, immigration and visas, housing, business compliance, engineering and science. Every guide links to a free tool that runs in your browser and keeps your figures private.
318 guides
Pro Calculators and Guides
How to Estimate Your US Paycheck After Federal Tax, Social Security, Medicare and 401(k)
Turn a US salary into take-home pay with federal income tax, FICA, 401(k) contributions and your state tax rate, per year, month, week and day.
Pro Calculators and Guides
How to Extract All Images From a PDF at Original Quality
Save every picture inside a PDF as its own file, in one ZIP, without taking screenshots of the page.
Pro Calculators and Guides
How to Extract Plain Text From an EPUB File
Get the text of an e-book as a TXT file you can copy, search or paste elsewhere, without images or formatting. Free and private.
Pro Calculators and Guides
How to Extract Plain Text From an ODT Document
Get the words from an OpenDocument Text file as a TXT you can copy or save, ignoring formatting, in your browser.
Pro Calculators and Guides
How to Extract Plain Text From an RTF File
Get the words from a Rich Text Format file as a TXT without the formatting codes, in your browser. Free and private.
Pro Calculators and Guides
How to Find a Bangladesh Mobile Operator From the Number Prefix
See which operator a Bangladeshi mobile number prefix belongs to: Grameenphone, Banglalink, Robi, Airtel or Teletalk, and why portability matters.
Pro Calculators and Guides
How to Find the Day of the Week for Any Date (Past or Future)
Find out what weekday a date falls on, like your birthday or a historical event, with the day number in the year.
Pro Calculators and Guides
How to Find the LCM and GCF (HCF) of Numbers, With Prime Factorisation
Calculate the least common multiple and greatest common factor of two or more numbers, with step-by-step methods and uses.