Keep the end date fixed
Delay is meaningful when both plans are trying to fund the same goal on the same date. Comparing a 20-year SIP with another SIP that starts two years later but still runs for 20 years hides the effect of arriving late. The delayed plan has 18 years left if the original goal date is unchanged.
At ₹5,000 a month, 12% nominal annual return and a 20-year goal, delaying two years creates an illustrative corpus gap of about ₹11.69 lakh under beginning-of-month contributions. Only ₹1.20 lakh of that gap is missed deposits; the rest is foregone modelled growth. Catching up requires roughly ₹6,527 per month over the remaining 18 years, at the same assumed return.
A contribution gap is different from a return forecast
The missed deposits are known arithmetic. The growth gap depends on an assumption that will not occur as a smooth constant in markets. Test lower returns and a shorter feasible saving period. If the catch-up contribution is unaffordable, changing the goal amount or date is more controllable than choosing an optimistic return.
Use the calculator
The annual table helps identify where deposits stop being the main source of the difference. It also prevents a common misunderstanding: the entire corpus gap is not interest on the missed ₹1.20 lakh alone. Those early contributions had longer to grow, and their absence changes every later balance.
Before increasing risk
Confirm that this is money available for a long-term goal, separate from urgent bills and emergency reserves. A calculator can solve a contribution requirement under an assumption; it cannot make that assumption reliable.