Index Cards Dimensions
The typical size of an index card in the US is 3 x 5 
inches (76.2 x 127 mm). It is for this reason that the card is known as a 3 by 5.
Other Sizes and Styles
Aside from 3 x 5, the index card is available in the following sizes: 4 x 6 inches (101.6 x 152.4 mm), 5 x 8 inches (127.0 x 203.2 mm) and ISO-size A7 (74 x 105 mm/2.9 x 4.1 in).
The cards are sold in various colors, but almost all are ruled and have a grid. There are also some cards with different trays and cases to contain the cards.
The following are some of the ways you can use index cards.
Writing Messages
You can use these cards to write messages, notes, reminders etc. Unlike Post-it notes, there’s no need to worry about the card falling off after you stick them. These cards can be tacked on boards so the message can be seen.
Listing Bills
Because the size of an index card varies, it can be used to list bills in many ways. The bills can be listed by the date, the amount to be paid, the due date, by company, the check number, the amount you pay in full and so on. It is possible to use different cards to list the bills in different ways.
It is possible to use the cards to track your bills. Get a card for the company you have to pay the bills to. This can be gas, electricity, water, rent, cable TV etc. Write the company name on top. Write the payment you make every month. A year’s worth of payments can fit in the card.
Homework Aid
For example, you can use the cards to take down notes. They can also be utilized for bibliographies. They can also be used in class to take notes. For convenience’s sake, use different colored cards for the different subjects.
Use as an Address Book
Get a file box and alphabet divider for the cards. This will be sufficient to make the address book. The dimensions of the cards make it easy to write and update the information.
The size of an index card makes it very versatile. Other ways to use the card include listing recipes, shopping lists, contact information and arranging other data. The cards may also be sued as flash cards, visual aids, take down presentation notes and many more.
