Simple interest is I = P x r x t, where P is the principal, r is the annual rate as a decimal, and t is the time in years. On 2,000 for 3 years at an example rate of 4 percent, that is 2,000 x 0.04 x 3 = 240 in interest. A free simple interest calculator does the math in your browser with no signup.
Interest = principal x rate x time, with the rate written as a decimal and the time in years. As an example only, a 2,000 loan for 3 years at an example rate of 4 percent earns 2,000 x 0.04 x 3 = 240, so you repay 2,240 in total. Because the rate never compounds, the interest is the same amount every year, which makes simple interest easy to reason about.
Simple interest is common on some short-term personal loans, car loans and bonds that pay a fixed coupon, while savings accounts and credit cards almost always compound instead. Knowing which one applies matters: over long periods compound interest produces noticeably more than the flat simple figure for the same rate.
240, using the example rate. The formula is 2,000 x 0.04 x 3, and the total to repay is 2,240.
Simple interest is calculated only on the original principal, so it is a flat amount each year. Compound interest also charges interest on accumulated interest, so it grows faster.
Yes. Convert months to years by dividing by 12. Six months is 0.5 in the formula.