What a lump sum plus monthly investing grows to over time.
Future value
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Total invested
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Interest earned
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Growth multiple
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Value in today's money
Balance growth
What builds the final balance
Year-by-year table
Year
Invested to date
Interest to date
Balance
A projection at a constant rate, not a forecast. Real returns vary and can be negative. This is not investment advice.
How this works
Lump sum: A = P × (1 + r/n)^(n×t)
Monthly SIP: FV = M × [((1 + i)^m − 1) ÷ i] × (1 + i)
$500/month at 10%
Invested
Final value
10 years
$60,000
≈ $102,000
20 years
$120,000
≈ $380,000
30 years
$180,000
≈ $1,130,000
Tripling the time multiplies the result about elevenfold — time beats contribution size.
Rule of 72: 72 ÷ return = years to double. At 8%, about 9 years.
Historic long-run equity index returns: roughly 7–10% a year before inflation.
Subtract inflation for real value — 3% over 15 years cuts buying power by about 36%.
Currency
Amounts follow the currency selected above.
Simple vs compound interest?
Simple interest pays only on your original deposit. Compound interest pays on the deposit plus interest already earned, so it accelerates. $10,000 over 20 years at 10% yields $30,000 simple, but about $67,000 compound.
What return rate should I assume?
Be conservative. Broad equity index funds have historically returned roughly 7-10% a year before inflation over long periods, with severe drops along the way. Projecting 15%+ will mislead you.
What is an annual step-up?
Raising your monthly contribution by a set percentage each year, usually with salary growth. A 10% step-up can lift a 15-year outcome by 40% or more, because each increase compounds for the years remaining.