Net worth projection

A net worth projection is a forward estimate of how a household’s net worth will evolve over time, based on the current position, expected savings, anticipated investment returns, and assumptions about major life events. It is the single most useful piece of forward-looking financial planning for most households, because it converts day-to-day financial decisions into a long-horizon trajectory the household can see.

What it includes

A complete net worth projection typically models:

• Current assets — cash, investment accounts, retirement accounts, property, vehicles, other significant assets
• Current liabilities — mortgage balances, personal loans, credit card balances, other debts
• Future contributions — regular savings into investment and retirement accounts, debt repayments
• Expected returns — assumed real or nominal growth rates for each asset class
• Major life events — home purchase, child-related expenses, education funding, retirement
• Time horizon — typically the household’s projected working life plus retirement

Each component is projected forward, summed, and the result tracked across time to produce a year-by-year (or month-by-month) net worth path.

Why it matters

Net worth projection is the connecting tissue between today’s financial decisions and tomorrow’s life options. Three specific applications recur:

Retirement readiness assessment. Projecting forward to retirement age reveals whether the current trajectory will produce a retirement-feasible portfolio. The projection often surfaces a gap that, addressed early, is much smaller than it would be if discovered in late career.

FIRE (Financial Independence, Retire Early) planning. For households pursuing financial independence ahead of conventional retirement, the projection identifies the timing at which assets are likely to support the desired withdrawal level — the FIRE number combined with expected returns and savings rate produces a projected FIRE date.

Major decision evaluation. Decisions like buying a property, taking a career break, sending a child through expensive education, or starting a business can each be modelled as adjustments to the baseline projection, revealing the long-run trajectory impact.

How sensitive projections are to assumptions

Net worth projections are highly sensitive to assumptions about expected returns and savings rates, particularly for long horizons. Small changes in inputs compound to large differences in outputs.

A one-percentage-point change in assumed real return — from 5% to 6% — applied across thirty years produces approximately 35% more terminal portfolio value. A 5% change in savings rate compounds to similarly large differences.

The implication is that any single projection is best understood as one scenario rather than a forecast. Robust planning typically runs multiple scenarios — conservative, central, and optimistic assumptions — to bound the range of plausible outcomes, then plans to make the conservative case workable rather than relying on the central case.

What a good projection should include

Several disciplines distinguish useful projections from misleading ones:

• Real (inflation-adjusted) values so future amounts can be compared to today’s spending
• Realistic return assumptions based on long-run historical averages, not recent strong performance
• Honest savings rate assumptions based on actual current savings, not aspirational future levels
• Major life events explicitly modelled rather than assumed away
• Sensitivity testing showing how the projection changes with different assumptions
• Periodic recalibration as actual results diverge from projection inputs

The most common error is over-optimism — assuming high returns, perfect savings discipline, no career disruptions, and no major unexpected costs. A projection robust to less-than-ideal assumptions provides much more confidence than one that depends on everything going well.