Month 1: “Why did almost nothing go to principal?” - everyone, eventually.
EMI (equated monthly installment) is the payment that wipes the balance at month n if the rate stays fixed and you pay on time. The emotional twist is amortization: early months are interest-heavy because interest accrues on the whole balance. That isn’t a secret fee; it’s how the algebra works. I wish someone had said that plainly before I stared at my first car statement.
If you want the shape of the formula
Monthly rate r = (APR/12)/100. Count of payments n. Principal P. Payment scales like P·r·(1+r)^n / ((1+r)^n − 1). You will never need to hand-derive this unless you’re studying for an exam; phones exist.
$12,000 · 9% · 36 months
Small enough to hold in your head. The EMI calculator should put the payment near $381, total interest somewhere around $1,720 over the life of the loan (a buck or two either way is normal). Try bumping to 11% on the same principal and watch payment jump about $35 - rates aren’t linear in the way our brains want them to be.
Prefer years in the UI? Loan calculator. Same engine, different labels.
Three things people still argue about
Fixed vs floating. Classic EMI assumes fixed rate until payoff. ARMs reset - different product, different stress.
“Interest first.” True early on; shifts toward principal later. Your amortization schedule is the receipt.
Balloon at the end? That’s not standard EMI. If the contract mentions a big final lump, read slowly.