Learn/Calculators/Returns and compounding

SIP delay cost calculator: what waiting to start costs.

Compare a SIP started today with the same SIP started a few years later, both ending on the same date. See what the wait costs and the monthly SIP needed to catch up.

Formula shown
Free, nothing stored
Share your result as a link

Monthly SIP

Delay before starting

Expected return a year

Reference returns, tap to use

Model, back tested, RupeeCase indices

All 18 indices, model, back tested CAGR

The default 12% is an assumption for illustration, not a forecast. Past or back tested returns are not a promise of future returns.

Years to the goal date, from today

Cost of waiting 5 years₹77.5 L46.0% of what starting now builds

Start now: value after 25 years₹1.69 Crinvested ₹30.0 L

Start in 5 years: value on the same date₹91.1 Linvested ₹24.0 L

Monthly SIP needed to catch up₹18,505for 20 years, 1.85 times the SIP

Extra each month to catch up₹8,505

Total invested to catch up₹44.4 Lagainst ₹30.0 L starting now

Cost of waiting at the Dynamic Asset Allocator model CAGR₹298.84 CrDynamic Asset Allocator, model, back tested CAGR 45.18% as of 27 Apr 2026. Not a promise of future returns.

Start now
Start in 5 years
Catch up SIP
Start now at the Dynamic Asset Allocator model CAGR

Both SIPs end on the same date; instalments at month end, monthly rate 0.949% from 12.0% a year.

01How it works

In plain words.

Two SIPs of the same amount end on the same date: one starts today, the other after the delay. The late SIP has fewer instalments, and it loses the stretch of compounding when the balance would have been largest. The calculator compares the two values, then solves the SIP formula backwards for the instalment that, started after the delay, reaches what starting now builds.

The formula

i = (1 + r)^(1/12) - 1; n = years x 12; n2 = (years - delay) x 12Start now = SIP x ((1 + i)^n - 1) / i; start late = SIP x ((1 + i)^n2 - 1) / iCost of waiting = start now - start lateCatch up SIP = start now x i / ((1 + i)^n2 - 1)

02Worked example

The default numbers, by hand.

Rs 10,000 a month at 12% a year for 25 years builds about Rs 1.69 crore. Started 5 years later, the same SIP runs 20 years and builds about Rs 91.1 lakh, so the wait costs about Rs 77.5 lakh, 46% of the value, while it skips only Rs 6 lakh of instalments. To reach Rs 1.69 crore in 20 years the SIP has to be about Rs 18,500 a month, 1.85 times as much, and about Rs 44.4 lakh goes in against Rs 30 lakh.

Input	Value
Monthly SIP	₹10,000
Delay before starting	5 years
Expected return a year	12%
Years to the goal date, from today	25 years

Result	Value
Cost of waiting 5 years	₹77.5 L
Start now: value after 25 years	₹1.69 Cr
Start in 5 years: value on the same date	₹91.1 L
Monthly SIP needed to catch up	₹18,505
Extra each month to catch up	₹8,505
Total invested to catch up	₹44.4 L
Cost of waiting at the Dynamic Asset Allocator model CAGR	₹298.84 Cr

03Key concepts

What to know before you use it.

Why the lost years cost so much

Compounding works on the balance, and the balance is largest at the end. Starting five years late removes five years of growth on the whole pot, not five years of small early balances, which is why the cost is far larger than the instalments skipped.

Ways to catch up

A later start can reach the same value with a larger SIP, a yearly step up or a longer horizon. The step up SIP calculator and the goal planner show the other two levers.

Good to know

A small SIP started now keeps the time on your side; it can be raised later with a step up.
At a higher assumed return the cost of waiting is larger, because each year of compounding is worth more. At 0% a delay costs only the instalments skipped.
A constant return is a simplification; actual values on any date can be above or below these lines.

04Assumptions

What the calculator assumes.

One constant return; instalments at the end of each month, no missed instalments.
Both SIPs end on the same date; the delay is in whole years.
Tax, exit load and expense ratio are not deducted; the capital gains tax calculator covers the tax on equity gains. The default 12% is an assumption for illustration, not a forecast.

05Questions

Asked about the SIP delay cost calculator.

What is the cost of delaying a SIP?

The difference between what a SIP started today and the same SIP started later are worth on the same future date. Rs 10,000 a month at 12% for 25 years against 20 years is a gap of about Rs 77.5 lakh.

How much more SIP do I need if I start late?

Solve the SIP formula for the shorter period: catch up SIP = target x i / ((1 + i)^n2 - 1). Starting 5 years into a 25 year plan at 12% needs about 1.85 times the SIP.

Does the cost of delay depend on the return?

Yes. The higher the return, the more each year of compounding is worth and the more a delay costs. At 0% a delay costs only the instalments skipped.

Explore next

Learn the idea behind the numbers.

Community

Join my WhatsApp group.

Scan the code, fillFill one short form, and join my WhatsApp group. Slides, sources, factsheets and the rebalance logs live there, and members join a daily Google Meet with me.

One form, one groupScan with your phone camera

06Keep going

Learn the idea, see it applied.

Module 2.1Why Rules Beat Gut Feeling9 min read, Path 02 Module 8.1Why Investors Lose: Introduction to Behavioural Finance11 min read, Path 08 The matching indexLarge Mid Hybrid40 equity stocks plus 20% LiquidCase. 80/20 equity-plus-debt on the LargeMidCap 250.CAGR33.2%Sharpe1.67Max DD−18.3%Model, back tested, as of 27 Apr 2026. Not client returns, not a promise. Risk band: Moderate.

Related calculators

SIP calculator Step up SIP calculator Goal planner Lumpsum calculator All 28 calculators

Education only, not investment advice. RupeeCase (QC Alpha Technologies Pvt Ltd) is not a fund, a PMS or a SEBI registered investment adviser. Model returns are back tested, not a promise; figures carry the date checked.