• Calculation & Conversion Tools : Websites that assist with mathematical calculations, including online calculators and conversion dictionaries and tables.
• Calculator City : A Web Resource for Mathematics
• Calculator.com : calculate anything anywhere... 
  online, pocket, pc, pda, wap and cellphone calculators.
• Kalkulator
• Measure 4 measure : A collection of interactive sites on the Web that estimate, calculate, evaluate, translate, etc. In other words. They do the work for you.
• Omregningskalkulator : lengde, areal, volum.
• OnlineConversion.com : Convert just about anything to anything else.
  Over 5,000 units, and 50,000 conversions.
• Scientific Calculator   
• Valutakalkulator  : fra DnB NOR