StepUpSIP LogoStep-Up SIP

The Math Behind the Magic

Understanding how increasing your Systematic Investment Plan contributions annually compounds over time.

The Step-Up SIP Formula

A geometric progression of monthly contributions, compounded at every period.

FV =∑nt=1SIPt ×(1 + r)n - t + 1

Variables Map

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    FV (Future Value): The total accumulated maturity wealth at the end of the investment duration.
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    SIPt (Contribution in Month t): The monthly installment amount, which increases at the start of each year (month 13, 25, 37...).
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    r (Monthly Interest Rate): Compounded equivalent monthly rate: r = (1 + Return % / 100)1 / 12 - 1.
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    n (Total Months): The total number of investment periods (Years × 12).

The 'Step-Up' Effect

Standard SIP equations assume a constant, static monthly principal. A Step-Up SIP modifies the monthly principal SIPt by multiplying it by (1 + Step-Up%) at the start of every 12-month interval.

This periodic raise builds a nested geometric progression. Compounding interest on a continuously increasing principal generates a hockey-stick growth curve, yielding vastly higher wealth in later years.

trending_upAn annuity-due convention is applied: investments are deposited at the start of each month, compounding for the full remaining months (including the month of deposit).

Step-by-Step Numerical Example

Sample Parameters

Initial SIP
₹10,000
Annual Step-Up
10%
Expected Return
12% p.a.
Duration
3 Years
1

Year 1: Flat Installment

Monthly SIP is ₹10,000 for months 1 to 12. Compounding monthly at 1% interest rate ($12\% / 12$):

Value at Year 1 End: ₹1,26,825
2

Year 2: Step-Up is Triggered

The monthly SIP grows by 10% at month 13. Monthly installment becomes ₹11,000 for months 13 to 24.

New Monthly SIP: ₹10,000 × 1.10 = ₹11,000
3

Year 3: Dynamic Accumulation

SIP steps up again at month 25 to ₹12,100. Previous balances continue to compound alongside new contributions.

Maturity Value (Year 3 End): ₹4,44,792
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Spreadsheet Pro Tip

The standard Microsoft Excel or Google Sheets `=FV()` function calculates constant payments only. To build a Step-Up SIP model, you must map it in a row-by-row schedule.

Set up columns for:

  • Month Index (1 to n)
  • Opening Balance
  • Monthly Contribution
  • Monthly Interest Earned
  • Closing Balance
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