What your result means
A step-up SIP raises your contribution on each anniversary, so the plan grows alongside your income instead of being frozen at whatever you could afford on day one. The total invested figure will therefore be far higher than a flat SIP at the same starting amount — the comparison worth making is not corpus against corpus, but what each plan asked of you month by month.
The increase compounds twice over. Each rise adds more capital, and that extra capital then has years left to grow. This is why a 10% annual step-up roughly doubles a twenty-year outcome while never once demanding a payment that felt like a jump at the time.
Choose percentage if you expect your salary to rise proportionally, and fixed amount if you would rather commit to something concrete like an extra £50 a month each year. The fixed-amount option is gentler early and much less demanding late — a 10% step-up on £500 is £50 in year one but £281 in year twenty.
A 10% annual increase nearly doubles a twenty-year SIP
Most people set a SIP once and never touch it again, which means inflation quietly shrinks their real contribution every year. A plan that felt ambitious in 2006 is a modest one by 2026 without anyone deciding to reduce it.
Stepping up by the same percentage as your pay rise keeps the contribution constant in the only terms that matter — as a share of what you earn. The month-to-month sacrifice never increases, but the outcome changes out of all recognition.
How it works
The calculation is identical to a standard SIP for the first twelve months. On each anniversary the monthly amount is multiplied by your step-up percentage, or has your fixed increase added to it, and the new amount runs for the following year.
Increases are applied annually rather than monthly because that is how pay rises and standing-order reviews actually happen. Every instalment continues to compound from the month it is paid, so the early, smaller contributions still carry most of the growth.
The year-by-year table shows the rising annual contribution in the "paid in" column, which makes it easy to see the point where the increases start to feel real — usually somewhere around year twelve.
How to use this calculator
- Enter your starting monthly investment.
- Set the annual increase, and choose whether it is a percentage or a fixed cash amount.
- Set the expected return and how many years the plan runs.
- Open Advanced options to add fund charges and inflation.
- Compare the result against the same plan with the increase set to zero — the difference is what stepping up buys you.
Formula
P = starting monthly amount, g = 1 + step-up rate, i = monthly return, Y = years. Each year's twelve instalments are compounded to the end of the term, then summed.
Worked example
£500 a month for 20 years at 12%, first flat and then with a 10% annual step-up:
+10% a year invested £343,650 → £931,569
Final monthly contribution £3,058
In today's money £515,787
The step-up plan more than doubles the corpus. It also asks for nearly three times as much money, so this is not free — the real claim is that the increases arrive at the same pace as your earnings, so no single year ever feels harder than the first one did. By year twenty you are paying £3,058 a month, which sounds impossible today and will not in 2046.
Frequently asked questions
What step-up percentage should I choose?＋
Match it to your realistic annual pay rise. In the UK that has typically been somewhere between 3% and 6%; 10% is common in Indian SIP planning where salary growth has been faster. Setting it above your income growth means the plan gets progressively harder, which is how step-ups get abandoned in year six.
Percentage or fixed amount — which is better?＋
A percentage keeps the contribution constant relative to your income and produces the bigger corpus. A fixed amount, such as £50 more a month each year, is easier to commit to and much gentler in the later years. If you are unsure, a fixed amount you will actually stick to beats a percentage you abandon.
Can I set up a step-up SIP automatically?＋
Most fund platforms and Indian AMCs offer a top-up or step-up SIP facility that raises the mandate automatically each year. If yours does not, a calendar reminder each April works just as well — the mechanism matters far less than doing it.
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Assumptions & limitations
The step-up model is deliberately simple. Worth knowing:
- Returns are assumed constant every year. Real markets are not — they deliver the average through a sequence of good and bad years, and the order those arrive in changes the outcome.
- Growth is compounded monthly from the annual rate you set, so 10% a year becomes 0.797% a month rather than a flat 0.833%.
- Fund charges are deducted monthly from the balance. Platform fees, trading costs and bid-offer spreads are not modelled separately — fold them into the charge figure if you want the full picture.
- Inflation is applied at a single constant rate to produce the "today's money" figures. Your personal inflation rate depends on what you actually buy.
- Nothing here is financial advice, and no projection is a promise. Use it to compare scenarios against each other, not to predict a number.
- Increases are applied once a year on the plan anniversary, and every increase is assumed to be affordable and paid in full.