First published: 25 September 2026 · Last updated: 25 September 2026
Concept: what it measures
The income replacement gap is the difference between what a household would need to stay financially stable if the primary earner died, and what it already has in place to cover that need. It's the number that tells you whether an existing life insurance policy — or the absence of one — actually closes the gap, or just narrows it.
The formula
Income Replacement Gap = (Annual net income × years of income replacement needed) + outstanding debts and mortgage balance + future major obligations (education, childcare, elder care) − liquid savings and investments − existing life insurance already in force
Each input is something a reader can pull from their own pay stubs, mortgage statement, and policy documents — nothing here requires an actuary.
Notes on the inputs:
- Years of income replacement needed is usually driven by the youngest dependent's age until financial independence (commonly 18–22), not an arbitrary round number.
- Future major obligations should be estimated conservatively and itemized, not lumped into a vague buffer.
- Existing coverage means only in-force life insurance, not retirement accounts earmarked for other goals.
US Worked Example
Consider Daniel, a 38-year-old in Columbus, Ohio, earning $75,000 a year after tax, with a spouse and two children aged 6 and 9.
- Annual net income: $75,000
- Years of replacement needed: 13 (until the younger child turns 22, taken as the intended cutoff for full financial independence)
- Income replacement need: $75,000 × 13 = $975,000
- Outstanding mortgage balance: $220,000
- Future obligation (two college educations, estimated): $160,000
- Subtotal need: $975,000 + $220,000 + $160,000 = $1,355,000
- Liquid savings: $30,000
- Existing term life coverage in force: $250,000
- Income Replacement Gap: $1,355,000 − $30,000 − $250,000 = $1,075,000
Daniel's family looks reasonably covered on paper with a $250,000 policy from his employer. The calculator shows that policy actually closes less than a quarter of the real gap — the kind of shortfall that only becomes visible when the calculation is run in full rather than estimated with a rule of thumb like "10 times salary" ($750,000 in his case, which would still have left him underinsured by more than $300,000).
UK Worked Example
Now consider Priya, a 41-year-old in Leeds earning £45,000 a year after tax, with a partner and one child aged 4.
- Annual net income: £45,000
- Years of replacement needed: 18 (until the child turns 22)
- Income replacement need: £45,000 × 18 = £810,000
- Outstanding mortgage balance: £180,000
- Future obligation (one university education, estimated): £45,000
- Subtotal need: £810,000 + £180,000 + £45,000 = £1,035,000
- Liquid savings and ISAs: £40,000
- Existing life cover in force (a decreasing-term policy tied to the mortgage): £180,000
- Income Replacement Gap: £1,035,000 − £40,000 − £180,000 = £815,000
Priya's mortgage-linked policy is a common UK default, but the calculation shows it only ever covered the mortgage line — it does nothing for the thirteen years of income replacement or the education cost sitting alongside it. A UK reader running this should also net off any Bereavement Support Payment they'd be entitled to from the Department for Work and Pensions, since that's a real, if modest and time-limited, offset most calculators built for a US audience wouldn't otherwise capture.
How to use it
Run the formula once now with current numbers, then rerun it after any major change — a new mortgage, a second child, a pay rise, or an existing policy lapsing — since the gap moves every time one of the five inputs does.
0 Comments