Overdraft loan calculator

An overdraft loan lets you draw money up to a sanctioned limit and pay interest only on what you use. Many lenders offer an initial interest-only period during which you pay only the monthly interest and the principal stays unchanged — useful for stretching cash flow before regular EMIs kick in. This calculator projects total interest, monthly cost, and the cumulative-interest curve, with the interest-only window highlighted.

Overdraft loan

Total cost
Interest-only EMI
Regular EMI (post-IO)
EMI / amortisation months
Total payable
Effective annual cost (APR, incl. fee)
Outstanding balance & cumulative interest

Month-by-month schedule

MonthOpening balanceInterestPrincipal paidTotal paymentClosing balance

How the calculation works

The calculator splits your tenure into two phases:

  • Interest-only phase (first N months) — you pay just the monthly interest on the full principal: P × r. Principal stays at P; no amortisation happens.
  • EMI phase (the remaining months) — full EMI kicks in: EMI = P × r × (1+r)ⁿ / ((1+r)ⁿ − 1), where n is the number of post-IO months. Each EMI payment splits into interest on the current balance plus principal repayment, so the principal starts amortising only at this point.

The total interest paid is higher than a same-tenure plain-EMI loan because the principal isn't reducing during the IO window — that's the trade-off for the lower early-month outflow.

FAQ

Are processing fees common on overdraft loans?

Yes, typically 0.5–2% of the sanctioned limit. Add it to the fee field; it's reflected in the effective annual cost figure.

How is interest-only different from interest-free?

Interest-only means you still pay interest, but only interest — your monthly outflow covers the financing cost while the principal stays put. Interest-free would mean zero charges; that's an introductory promo on some products, not the norm. This calculator models the interest-only scenario.

Why use an interest-only period?

Cash-flow management. If you've drawn the loan for a project that won't generate revenue for the first few months, paying just interest keeps the early outflow small. The total interest paid over the loan is higher than a same-tenure EMI loan because the principal isn't reducing during those months — that's the trade-off.

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