Parent Support Cost Calculator (total & split between siblings)

How it works

First-year cost = monthly allowance × 12 + extra yearly costs. Each later year is the previous year × (1 + increase). Total = the sum over all years, a growing series: C × [(1 + g)ⁿ − 1] ÷ g. Your share is the percentage you enter, or 1 ÷ number of siblings when you leave it at 0. Costs are in money of each year (not discounted).

⚠ Estimates for information only — not financial advice.

FAQ

How should siblings split the cost?

Families split equally, by income, or by who also gives time and care. Set your percentage to match what you agreed; the equal split is shown for comparison.

Should I include medical and care costs?

Yes, as an average yearly amount in “extra costs”. Long-term care can cost far more than a monthly allowance, so a separate care fund is worth planning for.

Checked 11 Nov 2026. Sum of a geometric (growing) series; family budgeting arithmetic. No external figures are used — enter your own amounts.