How Expense Ratios Compound Across 20 Years — The Math No One Shows You

A mutual fund expense ratio of 1.5% sounds small. It is, on a one-year view — 1.5% of your investment is the cost the fund deducts from the NAV every year to pay for management, distribution, custody, and audit. On a one-year view, the difference between paying 1.5% and paying 0.5% is exactly one percentage point of return — material but not transformative.

On a twenty-year view, the same one-percentage-point gap is a different animal. Compounding magnifies it. The fund manager’s alpha (or absence of it) has to overcome the expense gap year after year. By the time you reach year 20, the rupee value of “saving 1% in expense ratio” is much larger than the rupee value of “earning 1% extra return in year 20” — because the 1% saving compounded for the full 20 years, while the extra year-20 return only compounded for that one year.

This piece walks through the math properly. It shows you what 1%, 0.5%, and 0.25% expense-ratio differences do to your final corpus across realistic 20-year SIP horizons; explains why the impact is asymmetric (why a low expense ratio gives you back more rupees than the manager has to “earn” to make up for a high one); separates structural expense-ratio differences (direct vs. regular, equity vs. debt, large-cap vs. small-cap, index vs. active) from manager-skill differences; and finishes with a practical framework for evaluating expense ratio alongside other fund-selection criteria.

TL;DR - Best for: SIP investors with 15-25 year horizons evaluating fund choice - Min investment context: This piece is about cost compounding, not minimum SIP size — see GFS’s SIP framework for sizing - Lock-in: Not directly related (most equity funds have no lock-in; ELSS has a 3-year lock-in) - Key idea: A 1% expense-ratio difference compounded over 20 years costs roughly 18-22% of your final corpus — the math is structural, not anecdotal, and applies whether the fund underperformed or outperformed - Top risk (1 line): Selecting funds purely on low expense ratio without checking what you are losing on the management side — the cheapest fund is not automatically the best, and the highest-cost fund is not automatically a waste

What an expense ratio actually is

The expense ratio (Total Expense Ratio, or TER, in SEBI parlance) is the percentage of the fund’s average assets under management (AUM) that the asset management company (AMC) deducts every year to cover operating costs. It is set within limits prescribed under SEBI (Mutual Funds) Regulations, 1996, Regulation 52, which specifies maximum TER caps by scheme category and AUM slab — these were revised in 2018 to a sliding scale that drops as the fund’s AUM grows.

The TER is not a separate fee you pay. It is netted off from the fund’s gross returns inside the NAV calculation. If a fund’s gross return for the year is 14% and its TER is 1.5%, the NAV-quoted return you see is 12.5%. You don’t write a cheque for 1.5%; the fund just earns and credits 12.5% to you instead of 14%.

Two layers within the TER matter. The “scheme expenses” cover fund manager salary, research, custody, audit, registrar fees, marketing, and SEBI levies — these are the actual operating costs of running the scheme. The “distribution commission” is a separate slice paid to the distributor (the agent or platform through which the investor subscribed). Direct plans of a fund pay only the scheme expenses; regular plans pay scheme expenses plus distribution commission. The gap between regular-plan TER and direct-plan TER is typically 0.5-1% per year, depending on the AMC’s commission structure.

For equity-oriented funds in India in 2026, the typical TER ranges look like this: large-cap regular plans 1.5-2.0%, large-cap direct plans 0.7-1.2%, mid-cap regular 1.7-2.2%, mid-cap direct 0.9-1.4%, small-cap regular 1.8-2.3%, small-cap direct 1.0-1.5%, index funds direct 0.10-0.30%. These are not absolute bands — they vary by AMC and AUM — but they give the right order of magnitude.

The compound-cost math, properly

Start with a simple comparison. You SIP ₹10,000 per month for 20 years into two equity funds. Both deliver the same gross return — let’s say 13% per year. The only difference is the expense ratio. Fund A has a TER of 1.5%. Fund B has a TER of 0.5%. Net returns are therefore 11.5% and 12.5% respectively.

Plug into the future-value-of-SIP formula at the end of year 20:

•             Fund A (1.5% TER, net 11.5%): Final corpus ≈ ₹95.9 lakh

•             Fund B (0.5% TER, net 12.5%): Final corpus ≈ ₹1.10 crore

The gap is roughly ₹14 lakh on a total SIP investment of ₹24 lakh. That is the 1% TER difference compounded for 20 years on monthly contributions. In percentage terms, Fund A’s corpus is about 87% of Fund B’s — the 1% expense gap eats roughly 13% of your final wealth on this set of inputs.

The exact number depends on the gross-return assumption, the SIP duration, and the contribution profile. Across a range of realistic assumptions for Indian equity SIPs over 15-25 years, a 1% TER gap typically costs 12-22% of final wealth. The asymmetry — that you are losing 13-22% of the corpus, not just 1% — is what makes the expense ratio a structurally large lever even when it sounds small on paper.

Make the comparison sharper. What if Fund A has the same TER as Fund B but the fund manager generates 1% extra gross return through skill — pre-expense alpha? Fund A’s net return is 14%-1.5% = 12.5%, same as Fund B’s. The two funds end up with the same final corpus, and the manager has done all the work to overcome the expense disadvantage.

For the manager to actually leave you better off than a 0.5% TER fund, they need to generate 1% extra net alpha — which after expense is 1% extra gross alpha plus the expense gap, or roughly 2% gross alpha. That is a high bar to clear consistently for 20 years.

This is the asymmetric arithmetic that drives the entire passive-vs-active debate globally. It is not that active management does not work — it does, episodically. It is that for active management to leave the investor better off than a low-cost alternative, the manager’s pre-expense alpha has to overcome both the expense gap and the higher-tracking-volatility cost.

What 0.5% and 0.25% differences look like at 20 years

The math scales linearly in the percentage of corpus lost, but the rupee amounts grow large fast.

Same ₹10,000 monthly SIP for 20 years, same 13% gross return assumption:

•             TER 0.5% (net 12.5%): Final corpus ≈ ₹1.10 crore

•             TER 0.75% (net 12.25%): Final corpus ≈ ₹1.07 crore (3% lower than 0.5% case)

•             TER 1.0% (net 12.0%): Final corpus ≈ ₹1.04 crore (5.5% lower than 0.5% case)

•             TER 1.5% (net 11.5%): Final corpus ≈ ₹95.9 lakh (13% lower than 0.5% case)

•             TER 2.0% (net 11.0%): Final corpus ≈ ₹88.4 lakh (20% lower than 0.5% case)

A 0.25% gap costs roughly 3% of corpus. A 0.50% gap costs roughly 5.5%. A 1.00% gap costs roughly 13%. A 1.50% gap costs roughly 20%.

For larger SIPs, the rupee amounts scale linearly. A ₹50,000 monthly SIP at the same parameters — Fund A 1.5% TER vs Fund B 0.5% TER — produces a final-corpus gap of roughly ₹70 lakh after 20 years.

Looked at from another angle: the 1% TER on a ₹1 crore corpus is ₹1 lakh per year in absolute rupees. Compounded for 20 years on those rupees alone, the cost is several lakhs over the period. Layered on top of that, the AUM grows, so the absolute cost grows every year — the percentage cost stays at 1% of AUM but the AUM is much larger in year 20 than in year 1.

The intuition the math is delivering: the expense ratio is one of the very few inputs to long-term mutual-fund outcomes that is fully knowable in advance. Future returns are unknowable; risk-adjusted alpha by your specific fund manager is unknowable; sector outcomes are unknowable. The TER is contractually fixed in the offer document. Optimising the knowable variable while staying agnostic on the unknowable ones is a defensible discipline.

Why the cost is asymmetric (low-TER advantage > equivalent-return need)

Here is the asymmetry that makes the expense ratio matter more than equivalent returns. When Fund A has a 1% higher TER than Fund B, the investor in Fund A loses 1% of their portfolio every year. That 1% loss compounds for the full investment horizon — including the years when the portfolio is large.

For Fund A’s manager to fully offset the higher expense, they need to generate 1% extra net alpha — every year, consistently, for 20 years. The 1% extra alpha in year 20 is helpful but it only compounds for one year. The expense saving in year 1, in contrast, compounds for all 20 years.

Put differently: a 1% expense saving in year 1 on a ₹10 lakh portfolio is worth ₹10,000 in year 1, ₹11,200 in year 2 (because the saved ₹10,000 itself earns 12% return), ₹12,500 in year 3, and so on. By year 20, the year-1 expense saving (and its compounded growth) has crossed ₹1.06 lakh.

The 1% extra return that Fund A’s manager generates in year 20 on a (now-larger) ₹1 crore portfolio is worth ₹1 lakh in year 20 — meaningful but compounding for only one year before the investor exits.

The cleanest framing: low-TER advantages benefit you every year for 20 years. High-return-manager advantages only benefit you in the specific years they actually outperform. Most managers do not outperform every year. Even excellent active managers have multi-year underperformance windows.

When higher TER is justified (and when it is not)

The previous sections may sound like an argument for low-TER funds (direct plans, index funds) across the board. They are not. The argument is more specific: pay the higher TER only when you are getting something for it. Here is the typology of when higher TER is justified.

Justified — small-cap and certain sector funds where active selection still has edge. Small-cap equity is a less-efficient market than large-cap equity (less analyst coverage, larger information asymmetries, more dispersion in fundamentals). An active small-cap manager has more room to add alpha than a large-cap manager. The math: if a small-cap active fund has a 0.8% higher TER than a small-cap passive option, but the active manager historically delivers a 2-3% pre-expense alpha, the net advantage is positive. The trick is identifying managers who actually have that delivery track record, not just any active small-cap fund.

Justified — international and thematic funds where passive options are limited. International equity, sectoral, and certain thematic categories may not have low-cost passive alternatives in India in 2026, or the available passives may be too narrow. In these cases the active option is the only access, and the higher TER is paying for the access itself, not for alpha generation.

Justified — funds with strong long-term net alpha verified against an honest benchmark. Some active managers do deliver consistent net alpha. The verification needs to be: comparison against the right benchmark (large-cap funds against Nifty 100 Total Return, not against the S&P BSE Sensex), 5+ year track record under the current manager (not under their predecessor), and consistency rather than a single-year outperformance spike.

Not justified — large-cap active funds without consistent net alpha. Large-cap equity in India is increasingly efficient — the manager’s edge has shrunk as the institutional investor base has grown. Most large-cap active funds underperform the Nifty 100 TRI on a 5-10 year net-of-expense basis. Paying 1.0-2.0% TER for this category, when a low-TER passive option exists at 0.2-0.4%, is not justified for most investors. The math does not work.

Not justified — regular plans when direct plans of the same fund are accessible. Regular plans pay distribution commission on top of scheme expenses, raising the TER by 0.5-1% versus direct plans. Unless the distributor is providing material value (genuine financial planning, goal-setting, tax planning, behavioural support during drawdowns), the 0.5-1% TER gap is paying for distribution alone. For investors who can do their own fund selection or who have a direct relationship with an advisor compensated by a flat fee, direct plans win. See the direct vs regular plan cost comparison over a decade for the deeper walkthrough.

The expense-ratio decision inside a fund-selection process

Putting the expense-ratio analysis into the broader fund-selection process: it is one of five or six variables, and treating it as either the only variable or as irrelevant misses the point.

The typical evaluation sequence:

Step 1 — Category fit. Does this fund category match the role you want it to play in your portfolio? (Large-cap for stable equity exposure, mid-cap for growth, debt for stability, hybrid for moderation, ELSS for tax-saving with equity.) Cost analysis is irrelevant if the category is wrong.

Step 2 — Manager and process quality. Has the fund had stable management? Is the investment process consistent or does the fund’s character change with each manager change? Are the top 10 holdings consistent with the stated style?

Step 3 — Long-horizon consistency. Is the fund’s risk-adjusted performance reasonable across multiple cycles (5-10 years), not just in the recent bull period? Look at downside-capture during 2020 March, 2022 sell-offs, and similar drawdown windows.

Step 4 — Benchmark-relative net alpha. Has the fund actually beaten its appropriate benchmark net of fees over reasonable periods? For large-cap funds: Nifty 100 TRI. For mid-cap: Nifty Midcap 150 TRI. For small-cap: Nifty Smallcap 250 TRI. Comparing against a too-narrow or too-broad benchmark misleads.

Step 5 — Expense ratio in context. Now look at the TER. Is it justified by the manager’s net-alpha record and category-specific factors (small-cap, international, thematic)? Or is it eating into structural under-performance that no manager can overcome?

Step 6 — Other factors. Tax treatment (ELSS lock-in, equity LTCG ₹1.25L exemption), exit load, scheme size (very small or very large funds have different operational characteristics), and AMC reputation.

The expense ratio is a coherent decision input — but it has to sit inside this sequence, not above it. For more on the fund-selection process beyond historical returns, see how to evaluate a mutual fund without leaning on past returns. For broader SIP-decision context, see our SIP vs Lumpsum framework on Gayatrifin.

Concrete numbers: what to check before investing

Before committing to any equity fund SIP for 15-25 years, run these specific checks:

1.          Current TER for both direct and regular plans. Available on the AMC’s website and on AMFI’s monthly TER disclosure. Note both numbers.

2.          TER trend over the last 3 years. Falling TER as AUM grows is normal and good for investors. Rising TER is unusual and worth questioning.

3.          5-year and 10-year rolling returns vs. benchmark. Use Value Research or Morningstar India data. Compare net (post-expense) returns against the appropriate benchmark Total Return Index. If the fund consistently underperforms net of expense, the TER is not buying you anything.

4.          Manager tenure. Current fund manager’s track record on the specific scheme. Manager changes within the last 2 years reset some of the historical-track-record value.

5.          Direct-vs-regular gap. Specifically what you are paying for distribution. If you have direct fund-selection capability or a flat-fee advisor relationship, the direct plan is structurally better.

For investors with 15-25 year SIP horizons, the cumulative impact of disciplined expense-ratio evaluation can change the final corpus by 15-30%. That is bigger than most stock-picking edges. It is one of the few areas of investing where the math is fully visible in advance, and the right behaviour is just to follow what the math says.

FAQs

Q: How much does a 1% expense ratio cost over 20 years? A 1% expense ratio gap, compounded over 20 years on a typical SIP investment, costs roughly 12-22% of the final corpus depending on the gross return assumption. On a ₹10,000 monthly SIP at 13% gross returns, the difference between a 0.5% TER fund and a 1.5% TER fund is approximately ₹14 lakh after 20 years — on a total investment of ₹24 lakh. The exact amount scales with SIP size and time horizon.

Q: What is a good expense ratio for a mutual fund? A good expense ratio depends on the fund category and whether it is a direct or regular plan. For direct plans in 2026, large-cap equity funds typically come in at 0.7-1.2% TER, mid-cap at 0.9-1.4%, small-cap at 1.0-1.5%, and index funds at 0.10-0.30%. Regular plans add 0.5-1% to these numbers. Anything materially above these ranges needs justification through documented alpha generation.

Q: Does a low expense ratio guarantee better returns? A low expense ratio does not guarantee better returns — it guarantees a smaller drag on whatever gross returns the fund generates. The fund still needs to deliver returns through its underlying investments. A poorly-managed low-TER fund will underperform a well-managed higher-TER fund. The principle is: optimise the TER lever when other factors (category fit, manager quality, process consistency) are roughly equal. Do not pick a fund on TER alone.

Q: What is the difference between direct and regular plan expense ratios? Direct plan expense ratios are 0.5-1.0% lower than regular plan expense ratios for the same underlying fund. The gap is the distribution commission that regular plans pay to distributors (advisors, agents, platforms) and direct plans do not. The same fund manager, same portfolio, same investment strategy — the only difference is who handles the investor-onboarding and the distribution commission embedded in the regular-plan TER.

Q: How is mutual fund expense ratio deducted? Mutual fund expense ratio is deducted daily from the fund’s net asset value (NAV) — not as a one-time annual deduction. The NAV is calculated each day net of accrued expenses. Investors do not see a separate expense charge in their statements; they see the post-expense NAV directly. Over a year, the cumulative deduction equals the stated annual TER applied to the fund’s average AUM during that year.

Q: Can the expense ratio of a mutual fund change over time? The expense ratio of a mutual fund can change over time — and typically does. SEBI’s TER caps under Regulation 52 specify a sliding scale that drops as the fund’s AUM grows past certain thresholds, so a successful fund growing in size will see its TER cap reduce. AMCs may also adjust their TER within the cap based on competitive positioning. Investors should check the latest TER on the AMC’s website rather than relying on the figure at the time of investment.

Q: Are index funds always cheaper than active mutual funds? Index funds are structurally cheaper than active mutual funds because they do not pay for active management research and decision-making. The TER for Indian large-cap index funds is typically 0.10-0.30% direct, against 0.7-1.2% direct for large-cap active funds. The cost gap of 0.4-1.0% is meaningful when compounded over long horizons. Whether the active fund justifies the gap depends on its net alpha record.

Q: What is the maximum expense ratio a mutual fund can charge in India? The maximum expense ratio a mutual fund can charge in India is set by SEBI under Regulation 52 of the SEBI (Mutual Funds) Regulations, 1996, on a sliding scale by AUM. For equity-oriented schemes, the maximum TER for direct plans ranges from 1.0% to 2.25% depending on AUM tier. For debt schemes, the cap is lower. Regular plans can charge up to 1.25% above the direct plan cap, reflecting the distribution commission. Most active equity funds in 2026 charge well within these caps, especially as AUM has grown.