---
title: "Best SIP Date: Does the Day of the Month Matter? | RupeeCase"
description: "Is there a best SIP date? A ₹10,000 Nifty 50 SIP on each day from the 1st to the 28th, 2013 to 2026: XIRR 9.37% to 9.43%. What matters more than the date."
source_url: "https://www.rupeecase.com/guides/best-sip-date"
---

## Why people ask, and why the answer is small

The question comes up for good reasons. Fund houses let you pick any date; salaries arrive on different days; and a popular belief says the market is weaker late in the month, or right after the start of the month when money flows in. If that were true, a SIP set on the right date would buy more units every month for years.

Read one more paragraph, 65 words
The arithmetic says the gain, if any, has to be small. Every SIP date buys once a month, at a price within that month's range. Over 14 years the prices on the 5th and on the 20th of the same month are close to each other most of the time, and the differences go both ways. To find out how small, I ran the test.

## The test: every date from the 1st to the 28th

For each date from the 1st to the 28th, I simulated a ₹10,000 SIP in the Nifty 50 price index, buying at the first close on or after that date each month, from January 2013 to September 2026.

  XIRR of a ₹10,000 Nifty 50 SIP by date of the month, Jan 2013 to Sep 2026: nearly identical

    1. 1st**9.38%**

    2. 5th**9.38%**

    3. 10th**9.38%**

    4. 15th**9.39%**

    5. 18th, the lowest**9.37%**

    6. 24th, the highest**9.43%**

    7. 28th**9.41%**

  Nifty 50 price index, NSE daily closes; instalment at the first close on or after the date; valued 12 Oct 2026. Dividends, costs and tax left out. Past returns.

  **0.06**percentage points between the best and worst SIP date's XIRR

Nifty 50, Jan 2013 to Sep 2026

  **₹17,762**between the highest and lowest final value, on ₹16.5 lakh put in

Values on 12 Oct 2026

  **9.79%**XIRR buying at every month's lowest close, with perfect hindsight

NSE daily closes

  **9.04%**XIRR buying at every month's highest close, the worst luck possible

NSE daily closes

Read 3 more paragraphs, 197 words
Every version made 165 instalments, ₹16.5 lakh in all, and every one was valued at the 12 Oct 2026 close of 22,363.35. The XIRR accounts for the exact dates of each instalment, so a later date in the month is not penalised for being invested a few days less.

The spread between the best and worst date was 0.06 percentage points of XIRR. In rupees, the best final value (₹32,77,286, the 3rd) beat the worst (₹32,59,524, the 18th) by ₹17,762 after nearly 14 years, about 0.54%. To put that in context, the gap between a clairvoyant who bought at each month's low and an unlucky investor who bought at each month's high was 0.75 points, and no date-based SIP can come close to either.

One detail shows how much noise is in "the best date". The highest final value came from the 3rd; the highest XIRR from the 24th. A SIP on the 24th invests a few weeks later each month, so it ends with slightly less money but earned more per rupee per year. Depending on which number you rank by, you get a different "best date". That is what a meaningless difference looks like.

## The best date did not stay the best

If one date were truly better, it should win in most periods. It did not.

  SIP XIRR by date and period: the rows differ hugely, the columns barely

| Period | 1st | 5th | 10th | 15th | 20th | 25th | 28th |
| --- | --- | --- | --- | --- | --- | --- | --- |
| 2013 to 2016 | 6.06 | 6.13 | 6.12 | 6.15 | 5.95 | 6.21 | 6.19 |
| 2017 to 2020 | 14.10 | 14.05 | 14.04 | 14.16 | 14.12 | 14.21 | 14.09 |
| 2021 to 2023 | 16.19 | 15.94 | 15.81 | 15.82 | 16.42 | 16.68 | 16.57 |
| 2024 to Oct 2026 | -4.89 | -4.77 | -4.91 | -4.97 | -5.09 | -5.21 | -5.00 |

  ₹10,000 a month in the Nifty 50 price index on each date, valued at the last close of each period (12 Oct 2026 for the last). NSE daily closes. Past returns.

    **Myth**SIPs late in the month buy cheaper, so they return more.

    **Fact**On the Nifty 50 from 2013 to 2026, every date from the 1st to the 28th gave an XIRR between 9.37% and 9.43%. No date led in every period.

Read one more paragraph, 88 words
The 25th happened to lead in three of the four periods and came last in the fourth, 2024 to 2026, when the 5th led. More important is the pattern down the table: the period you invested through moved the XIRR from about −5% to about 16%. The date moved it by a fraction of a point. What decides a SIP's result is which years it runs through and how long it keeps running, which is why the [how long to stay invested guide](/guides/how-long-to-stay-invested) is the more useful read.

## Calendar effects exist, and still do not move a SIP

Researchers have long found small calendar patterns in daily returns, and the Nifty 50 shows some too. From 2012 to 2026 the average session in the first three trading days of a month and on its last day rose 0.088%, against 0.033% on the other days. Mondays averaged −0.016% and Tuesdays +0.084%. Days in the first half of the month averaged 0.055%, the second half 0.033%.

Read one more paragraph, 115 words
These averages sound like an edge, and they are why the question keeps coming back. They do not survive into a SIP for two reasons. A SIP buys once a month, so what matters is the price level on the purchase day, not the return of that day; a few hundredths of a percent of daily drift shifts that level by almost nothing. And the patterns are averages of very noisy numbers: on any single month, the gap between the 5th and the 20th is decided by that month's news, not by the calendar. The XIRR test above is the honest summary of both effects together: 0.06 points from the best date to the worst.

## What does matter for a SIP

If the date is a rounding error, these are not:

* **The amount**
* **Raising it each year**
* **Not pausing in a fall**
* **Starting**
* **The instalment going through**

Read a list, 162 words

* **The amount.** At the 9.4% XIRR of this test, ₹1,000 more a month for 14 years adds about ₹3.5 lakh. No date choice comes close to that.
* **Raising it each year.** A flat SIP shrinks in real terms as your income and prices rise. The note [the flat SIP shrinks](/blog/2026-07-30-morning-flat-sip-shrinks/) and the [step up SIP calculator](/learn/tools/step-up-sip-calculator) show the effect of a yearly increase.
* **Not pausing in a fall.** The instalments of March and April 2020 bought the Nifty at levels last seen in 2016 and 2017. The note [pausing a SIP in a downturn](/blog/2026-06-28-evening-pausing-sip-downturn/) puts a number on stopping at the wrong time.
* **Starting.** Waiting for a good month to begin costs more than any date choice; the note [the cost of waiting](/blog/2026-06-14-evening-cost-of-waiting/) works it through.
* **The instalment going through.** A bounced auto debit is a missed instalment and often a bank charge. Set the date a few days after your salary arrives, when the account is sure to have the money.

## Picking a date in practice

Since the date does not change the expected result, choose it for convenience:

Read one more paragraph and a list, 132 words

* A few days after your salary or business income usually lands, so the debit never bounces.
* If you hold several SIPs, either spread them across the month or put them on one date; neither changes the return, but one date is easier to track.
* Keep the date, and change it only if your pay date changes. The [module on building systems that protect you from yourself](/learn/path-8/module-8-6-building-systems-that-protect-you-from-yourself) explains why a fixed, boring routine beats a clever one.

The same reasoning applies to a [SIP in stocks](/guides/sip-in-stocks), where each instalment buys whole shares, and to the comparison of a [lump sum or SIP](/guides/lump-sum-vs-sip). To check the return of your own SIP with its real dates, use the [XIRR calculator](/learn/tools/xirr-calculator); the [CAGR vs XIRR guide](/guides/cagr-vs-xirr) explains why XIRR is the right measure for a SIP.

## How this shows up in RupeeCase

1.

1A due rebalance shows on the Dashboard and as a badge on the tab bar.
2.

2The portfolio says a rebalance is due.
3.

3Confirm rebalance says when it fell due and asks for your consent.
4.

4The strategy’s History tab records the turnover at every rebalance in the model record.
5.

5Every rebalance in the model record: the date, the turnover and the stocks added and removed.

Where it sits in RupeeCase, in words
A RupeeCase strategy rebalances on its own published calendar, which is set in advance and is not chosen to catch a particular day of the month, for the same reason this test shows. [Focused Largecap 20](/strategies/focused-largecap-20) holds 20 large companies by a momentum rule, rebalanced every 4 weeks: model CAGR 26.29%, deepest fall −23.56%, as of 27 Apr 2026.

## Questions investors ask

Which date is best for a SIP?None stood out. On the Nifty 50 from Jan 2013 to Sep 2026, a ₹10,000 SIP on any date from the 1st to the 28th gave an XIRR between 9.37% and 9.43%. Pick the date that suits your cash flow.

Is a SIP on the 1st better than one on the 28th?In this test the 1st gave 9.38% and the 28th 9.41%, a gap of 0.03 points over nearly 14 years. In 2024 to 2026 the order reversed. The difference is noise.

Does the SIP date matter for mutual funds?The test used the Nifty 50 index, which an index fund tracks before costs. For any diversified fund the same logic holds: one purchase a month at a price within that month's range, so the date changes the result very little.

Is it better to do a weekly or daily SIP?This test did not cover weekly SIPs. Since every date of the month ended within 0.06 points of the others, spreading the same amount across the month is unlikely to change much, and it adds transactions.

What if my SIP date falls on a holiday?The purchase happens on the next business day. In this test, every instalment that fell on a holiday or weekend bought at the next close, which is how the results above were calculated.

Should I change my SIP date after a market fall?There is no evidence in this test that any date does better after a fall. What helped was keeping the SIP running through the fall.

SSources

## Where the figures come from.
Show the 3 sources

1. NSE daily index files, Nifty 50 closing values, Jan 2013 to 12 Oct 2026. [nseindia.com](https://www.nseindia.com/)
2. Calculation: ₹10,000 a month on each date from the 1st to the 28th, bought at the first close on or after that date, Jan 2013 to Sep 2026 (165 instalments); XIRR and value on 12 Oct 2026; the same SIP at each month's lowest and highest close; sub period XIRRs valued at each period's last close.
3. RupeeCase lineup data, as of 27 Apr 2026: Focused Largecap 20 model CAGR and deepest fall.

  ASee it on RupeeCase

## Focused Largecap 20
20 largecap stocks, 4-week rotation. Pure equity on the Nifty 100. Rebalanced every 4 weeks, in your own demat. Moderately High risk band.

  [Sign up for RupeeCase](https://invest.rupeecase.com/signup?strategy=focused-largecap-20)[XIRR calculator](/learn/tools/xirr-calculator)

  [CAGR26.3%Sharpe1.20Max DD−23.6%Minimum₹1,00,000Model, back tested, as of 27 Apr 2026. Minimum as of 8 Aug 2026. Not client returns, not a promise.](/strategies/focused-largecap-20)

    Explore next

## Go deeper on this question.

* [GuideHow to invest in momentum stocks in IndiaThe rule, the three routes, the costs and the falls you sign up for.](/guides/how-to-invest-in-momentum-stocks)
* [GuideSmart beta in India: factor investing on NSE, explainedSix NSE factor indices against the Nifty 50, with the dated returns.](/guides/smart-beta-india)
* [GuideSIP in stocks: how a stock SIP works, and when a fund SIP is betterWhole shares, charges per instalment, tax by lot, and when a fund SIP wins.](/guides/sip-in-stocks)
* [GuideLump sum or SIP: what to do with money you already haveEvery start month in our record, the Dec 2024 peak, and how to choose.](/guides/lump-sum-vs-sip)
* [GuideCAGR vs XIRR: which return number to use, worked on a real SIPOne amount in, use CAGR. Money in on many dates, use XIRR. A real SIP, worked three ways.](/guides/cagr-vs-xirr)
* [Free module 8.6Building Systems That Protect You From Yourself9 min read](/learn/path-8/module-8-6-building-systems-that-protect-you-from-yourself)

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## Keep reading.

* [Investing monthlySIP in stocks: how a stock SIP works, and when a fund SIP is better](/guides/sip-in-stocks)
* [Investing a lump sumLump sum or SIP: what to do with money you already have](/guides/lump-sum-vs-sip)
* [Returns mathsCAGR vs XIRR: which return number to use, worked on a real SIP](/guides/cagr-vs-xirr)

  [All 46 guides](/guides/)

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Model figures are back tested on NSE data after costs, as of the date shown: not client returns, not a promise. RupeeCase is not a mutual fund, PMS, AIF or SEBI registered investment adviser; this is education, not investment advice.

About the figures and RupeeCaseIndex and fund figures carry their source and date. RupeeCase is a technology platform operated by QC Alpha Technologies Pvt Ltd. Research by QC Alpha Research Pvt Ltd, SEBI research analyst registration pending. Trades execute through your own SEBI registered broker and the shares sit in your own demat. Investments in securities markets are subject to market risks.