Finance Tools

What these finance tools cover

Two questions account for most of the arithmetic in personal finance, and this category splits along that line. The loan calculators answer what borrowing will cost you — the monthly instalment, the total interest over the term, and the charges that are quoted separately from the rate. The growth calculators answer the opposite question: what a sum becomes if you leave it alone and keep adding to it.

Each loan type gets its own calculator rather than one with a dropdown. A home loan has an amortisation schedule and tax relief under Sections 80C and 24(b); a car loan has on-road charges that are settled at the dealership; a personal loan is unsecured and priced accordingly. Those are different forms, not one form with the labels changed.

Choosing between them

Start from what you already know. If you know the amount you want to borrow, a loan calculator gives you the instalment. If you know the instalment you can afford, work backwards by adjusting the amount until the figure fits — which is usually the more useful direction, because affordability is the real constraint.

For investing, the distinction is whether you are contributing once or every month. The compound interest calculator projects a lump sum with optional additions; the SIP calculator is built around a monthly contribution and can also solve the other way, from a target amount back to the contribution it needs.

• Borrowing for a house, with tax relief and a year-by-year schedule — Home Loan Calculator.
• Borrowing for a vehicle, including insurance and registration — Car Loan Calculator.
• Borrowing without collateral, at a higher rate — Personal Loan Calculator.
• Growing a lump sum, with or without top-ups — Compound Interest Calculator.
• Investing a fixed amount each month, or solving for a goal — SIP Calculator.

What the numbers are not

Every figure here is an estimate from the inputs you give. A lender prices your actual loan from your credit history, income and its own policy, and the rate you are offered may not be the rate you modelled. Confirm the final figures with the lender before you commit to anything.

The investment projections are arithmetic, not forecasts. A returns assumption you type in is compounded exactly as typed; markets do not deliver a steady annual percentage. Where a tool offers an inflation adjustment, use it — the difference between a nominal and a real figure over twenty years is large enough to change a decision.