It depends on the card’s rewards program. As a rule, general travel rewards credit cards have a redemption ratio of 1 mile = 1 penny. So, you will basically need to multiply the cost of your ticket by 100 to see how many miles you will need. Thus, if an airline ticket costs $265, you will need 26,500 miles to cover the cost.
If you are using frequent flyer miles, then they work a bit differently. Most airlines have redemption charts where you can see how many miles you need for domestic and international flights. Note that those redemptions do not include taxes and fees, they are paid additionally in cash when you book your award ticket.
Disclaimer: This editorial content is not provided or commissioned by the credit card issuer(s). Opinions expressed here are the author's alone, not those of the credit card issuer(s), and have not been reviewed, approved or otherwise endorsed by the credit card issuer(s). Reasonable efforts are made to present accurate information, however all information is presented without warranty. Consult a card's issuing bank for the terms & conditions.
All rates and fees, and other terms and conditions of the products mentioned in this article/post are actual as of the last update date but are subject to change. See the current products' Terms & Conditions on the issuing banks' websites.