The short answer
The honest answer is that no published figure will be right for your family, because lifetime care cost is driven by variables that differ enormously between two children with the same diagnosis: how many years of care remain, how much paid support is needed, whether housing is owned or rented, and how fast the specific costs you carry inflate.
What does work is building the number from what you already know. Take what your child's care costs today across the categories that actually recur — daily living, paid caregiving, health and therapies, education or vocational programmes, and a contingency for the year that goes wrong. Carry those forward across the number of years care is likely to be needed. Apply inflation, because care costs — which are mostly wages — historically rise faster than general prices. Then subtract what already exists to meet it: savings, investments, property intended for their benefit, any income they receive, and life cover.
The result is not a prediction. It is your own arithmetic made visible, and its main use is not the total at the bottom. It is that you can change one assumption — care needed for forty years instead of thirty, paid support rising, inflation a point higher — and watch what that does. The shape of your exposure is more useful than any single number.
Most families find the figure is large and also that the gap is smaller than the total, because they had never counted what was already in place.
What changes the answer
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How many years of care remain
The single largest driver. Life expectancy for many lifelong conditions is close to typical, which can mean fifty or sixty years of costs, not twenty.
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How much paid support is required
Care is mostly wages. The move from family-provided to paid support is usually the sharpest single increase a plan ever has to absorb — and it is exactly what happens when a parent is no longer there.
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Housing, and whether it is owned
An owned home removes the largest recurring cost from the projection. A rented one leaves it in, rising, for the whole period.
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Health and therapy intensity
Some conditions carry predictable lifelong therapy costs; others are stable for years and then step up. Which pattern yours follows matters more than the current monthly figure.
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The inflation rate you assume for care
Over decades this dominates. A single percentage point of difference compounds into a very large gap.
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Existing income and entitlements
Any pension, benefit or income your child receives in their own right reduces what the corpus has to carry.
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Who else may contribute, and whether that is real
An assumed contribution from a sibling or relative that has never been agreed should not be in the projection at all.
What parents often miss
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Counting today's costs, not tomorrow's
Families project what they currently spend, forgetting that much of the care is currently unpaid and performed by them. The moment it has to be bought, the figure changes sharply.
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Underestimating the duration
Planning to age sixty when the realistic horizon is eighty is not a small error — it is a third of the cost missing.
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Using general inflation for care costs
Wages and health costs have historically outpaced the headline rate. Using the headline rate quietly understates the total.
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Forgetting the transition itself costs money
Setting up a new living arrangement, legal applications, deposits and overlapping costs all land at once, at the worst moment.
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Leaving the number unshared
A figure only one parent has seen is not yet a plan. Whoever will actually manage this needs to know it.
How the arithmetic moves
A family spends roughly a set amount each month on their son's care today. Most of his day-to-day support is provided by his mother, unpaid.
Projected naively, the total looks manageable. Projected honestly — with his mother's work replaced by paid support at market rates, over a horizon that runs to his eighties rather than his sixties, at care-cost inflation rather than headline inflation — the figure roughly triples.
That is not a reason to stop. It is the first accurate thing they have ever had. It also immediately shows that their existing life cover, bought a decade ago against a much smaller assumption, is the specific thing most out of date — which is a solvable problem they could not see before.
What to do next
Care Cost Planning builds the projection from the figures you enter, in INR or USD, with every assumption visible and adjustable. Start with the costs you can recall without looking anything up — blanks stay visibly blank rather than becoming numbers nobody checked.
No account, nothing saved to LegacyNest, and the report is yours to download.
Related planning areas
Important
This page explains how families think about the arithmetic of lifetime care. It is not financial, investment, insurance or tax advice, and LegacyNest does not recommend products, schemes, allocations or providers. A projection is a consequence of the assumptions you give it, not a forecast of what will happen. Talk to a qualified financial adviser before acting on any figure you produce here.