Surplus: income minus expenses
Surplus is the simplest possible measure of your finances: what's left over each month after expenses are subtracted from income. For a ₹1,00,000 monthly income and ₹65,000 in expenses: ₹1,00,000 − ₹65,000 = ₹35,000 surplus.
A tighter budget, ₹60,000 income and ₹58,000 expenses
Not every budget has that much breathing room. With ₹60,000 income and ₹58,000 expenses, the surplus is only ₹2,000, and the savings rate is 2,000 ÷ 60,000 × 100 = 3.3% — a real surplus, but a much thinner margin than the first example.
When surplus reaches zero
If income and expenses are exactly equal — ₹60,000 and ₹60,000 — the surplus is ₹0 and the savings rate is 0%. That's the break-even point: every rupee earned is already spoken for, with nothing left to save and no deficit either. Spending even slightly more than that would push the surplus negative.