SIP and compound interest scenario calculator
Model a hypothetical monthly SIP, a lump sum or both in rupees. See the full amount with Indian digit grouping, plus lakh or crore equivalents. Compare contribution and annual-rate assumptions without choosing a fund or predicting returns.
Your SIP or savings scenario
An editable example, not a return forecast. Amounts stay in this page and are not saved.
Correct the marked entry to calculate. Previous results are hidden.
Projected balance
Contributed capital
Modeled growth
Equivalent rates
Purchasing-power value
Scenario comparison
Yearly breakdown
| Years elapsed | Regular deposits | Contributed capital | Modeled growth | Projected balance |
|---|
Contributions and growth over time
Solid line: projected balance. Dashed line: contributed capital. A balance below contributed capital means a modeled loss. All values are also in the yearly table.
Hypothetical constant growth, before fees and taxes. Contributions use equal annual intervals, not a bank calendar. No investment recommendation or guaranteed return.
Try changing only the regular contribution or assumed rate in “Compare another scenario”. The baseline remains visible so you can see what caused the difference.
Understand the calculation conventions
Nominal vs effective annual interest: compare like with like
Understand why the same displayed annual percentage can produce different balances, with independently checked contribution examples.
An effective annual rate already includes compounding
At 5% effective annual growth, 10,000 becomes 10,500 after one year without contributions. The annual factor is G = 1 + 0.05. Its equivalent monthly rate is G^(1/12) − 1. Dividing 5% by twelve and then compounding monthly describes a different, nominal-rate scenario; it must not be applied to APY or AER again.
A nominal annual rate needs a compounding frequency
For 5% nominal annual interest compounded monthly, G = (1 + 0.05/12)^12. That gives an effective annual rate of approximately 5.116190%. With 10,000 initially and 100 at each month end over ten years, the balance is 31,998.32. At 5% effective annual growth, the otherwise identical scenario gives 31,725.26. The difference comes from the annual-rate convention, not extra contributions.
Keep the assumptions together
A SIP is a method of contributing regularly, not an investment product or promised return. The same displayed 12% annual assumption gives different results when interpreted as effective annual growth or a nominal rate compounded monthly. At ₹5,000 monthly for ten years with beginning deposits, those scenarios give ₹11,20,179.45 and ₹11,61,695.38 respectively, before fees and taxes. Read the equivalent annual and contribution-period rates beside the result. Rates are constant hypothetical inputs, not quoted offers or predictions. Fees, taxes and changing market returns are excluded. When comparing scenarios, change only the contribution amount or rate and keep the basis and payment timing explicit.
Beginning vs end contributions and partial periods
See when deposits enter the calculation, how many are counted, and why timing changes a result without changing contributed capital.
Beginning deposits have longer to grow
With 10,000 initially, 100 monthly for ten years and 5% nominal interest compounded monthly, end deposits give 31,998.32. Beginning deposits give 32,063.02. Both count 120 regular deposits and 22,000 of total capital. The 64.70 balance difference comes from one extra monthly growth interval for each contribution; it is not additional saving.
Whole-month input can still contain a partial contribution period
Take a one-month horizon, no starting capital and 100 paid quarterly. End timing counts no deposit because the quarter has not finished. Beginning timing counts one deposit immediately, giving 100 × G^(1/12) at the horizon. A zero-length horizon counts no recurring deposits in either mode. The starting balance remains separate from every recurring payment.
Reconcile the balance with the actual deposit count
Capital equals the initial amount plus the deposit count times the regular contribution. Growth is balance minus that capital and can be negative. Weekly means 52 equal annual intervals and fortnightly 26, not actual dated bank payments. The table includes annual boundaries and a final partial year. Compare one changed amount or rate only after checking these conventions.
How it works
Separate your contributions from modeled growth
Enter a starting balance and an amount per contribution interval. The projected balance adds the grown starting capital to every contribution grown from its modeled payment time. Capital is shown separately from growth, including negative growth. The yearly table includes deposit counts and a final partial year, so the total is traceable to the assumptions.
Make the annual rate and payment convention explicit
A SIP is a method of contributing regularly, not an investment product or promised return. The same displayed 12% annual assumption gives different results when interpreted as effective annual growth or a nominal rate compounded monthly. At ₹5,000 monthly for ten years with beginning deposits, those scenarios give ₹11,20,179.45 and ₹11,61,695.38 respectively, before fees and taxes. End deposits are counted only at completed intervals; beginning deposits at their start. A zero horizon counts no regular deposits. Optional inflation changes the purchasing-power figure only, not the nominal balance. Compare one changed rate or contribution while preserving these conventions.
Common questions
Why do two calculators give different totals?
Check the rate basis, compounding frequency, deposit timing and counted payments. A 5% nominal rate compounded monthly is not 5% effective annual growth. Partial periods and intermediate rounding can also differ. This calculator keeps full internal precision and displays the actual payment count and equivalent rate.
Are contributions made at the beginning or end?
You choose the timing; the default is the end of each interval. Beginning deposits grow for longer. With a one-month horizon and quarterly payments, end timing counts zero deposits and beginning timing counts one. At zero duration neither mode counts a recurring deposit.
Is this a guaranteed return?
No. This is constant-rate hypothetical mathematics before fees and taxes. Real investment returns vary and can be negative. No product is recommended. Assumed inflation is also a scenario input, not a forecast. Editable example rates are not current achievable returns or financial advice.
Practical guides
Scope and limitations
Constant hypothetical growth before fees and taxes; no financial product selection, guaranteed return, tax or account eligibility calculation. Equal annual intervals do not reproduce bank dates, business-day accrual or account-specific terms. Entered amounts stay in this page’s memory and are not saved.