Numerari from KnowledgeDoor---The scientific calculator with graphing, unit keypads,
complex numbers, constants, advanced functions, user-defined keys, quick copy, and more! Learn more (Link leaves KnowledgeDoor website)


We are very interested in your comments about our site. We may not be able to send a personal reply but we will try to use your comments to improve our content. You can use the form below or you can send comments to

Note: If you do not include your email address, we cannot respond to you.


Heaven's Boulevard astronomical sky image for any location, date, and time. Personalize with a picture and message. Great gift for birthdays, anniversaries, or any special event. Learn more (Link leaves KnowledgeDoor website)