How much does simple interest pay?

Interest on the original principal only — no compounding. The baseline your bank actually quotes.

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Interest earned
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Total balance
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Annual interest
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Interest as % of principal
What is simple interest?Interest = P × r × t on the original principal only. $10,000 at 5% for 3 years = $1,500. No interest on interest — that's why compound wins long-term.
Where is simple interest actually used?Car loans and some short-term consumer loans quote simple interest; bonds pay fixed coupons. Mortgages amortize, which is different from either.
Simple or compound — which is fair?Simple is fair for short loans; compound reflects reality for savings. If a loan charges interest on interest, it's compound — read the APY not the headline.