Disability Insurance Needs Calculator
Estimate the monthly disability insurance benefit you would need on top of existing income sources to cover essential expenses.
Content updated August 18, 2026
This is a needs estimate, not a quote or a benefit amount an insurer has approved. Actual disability policies cap the benefit as a percentage of income, may reduce it for other income sources, and apply waiting (elimination) periods before payments start.
Disability insurance replaces a share of your income if illness or injury keeps you from working. According to the NAIC, a typical individual disability policy replaces around 60% of pre-disability earned income — full replacement is rarely offered, partly so there remains a financial incentive to return to work when able.
This calculator turns that into two concrete numbers: the monthly benefit you would need on top of income you would already have, and whether that existing income already covers your essential monthly expenses.
The Disability Insurance Needs formula
Target monthly benefit = monthly gross income × (desired replacement % ÷ 100); Monthly benefit gap = max(target monthly benefit − existing monthly benefits, 0); Expense shortfall = max(monthly essential expenses − existing monthly benefits, 0)both gap figures are floored at zero, since a negative gap simply means existing income already meets or exceeds that comparison.
Worked example
A monthly gross income of 6,000 with a 60% desired replacement gives a target monthly benefit of 3,600. With 1,200 of existing monthly benefits already available, the monthly benefit gap is 2,400. Against 3,500 of monthly essential expenses, the existing 1,200 leaves a 2,300 expense shortfall if no new coverage is added.
Assumptions, rounding, and limitations
Assumptions
- The desired replacement percentage is chosen by the user rather than fixed by the calculator, since actual policy limits vary by insurer.
- Existing monthly benefits are treated as a single guaranteed figure available every month of a disability.
- Essential expenses are a flat monthly figure with no adjustment for reduced work-related costs or increased costs such as medical care during a disability.
Rounding: All figures are computed at full floating-point precision and rounded only for currency display.
Limitations
- This is a needs estimate, not a benefit amount an insurer has approved or a premium quote.
- Does not model elimination (waiting) periods, benefit periods, or how a specific policy's own income-replacement cap is defined.
- Treats income and expenses as fixed rather than changing over the course of a disability.
- Not personalized financial, insurance or tax advice.
Sources
- If a Disability Were to Keep You From Earning a Living, How Would You Pay Your Bills? — National Association of Insurance Commissioners (NAIC)
- A Workers' Most Valuable Asset — National Association of Insurance Commissioners (NAIC)
Target benefit and the coverage gap
The target monthly benefit is your monthly gross income multiplied by the income replacement percentage you choose. Subtract any existing monthly benefits — employer-provided long-term disability, Social Security disability, or other guaranteed income — and what remains is the monthly benefit gap a new or additional policy would need to close.
Checking the number against your actual expenses
A replacement percentage of income does not automatically match what you actually spend. The calculator separately compares your existing monthly benefits against your essential expenses — housing, food, utilities, transportation — and reports the shortfall if existing income alone would not cover them.
This is the check consumer guidance consistently recommends: work from what your household would actually need to spend, not only from a percentage of your old paycheck.
Short-term versus long-term disability
Short-term disability policies typically replace income for about three to six months. Long-term disability generally begins around six months after the disability starts and can continue for years or until retirement age. Many people carry both, with long-term coverage picking up where short-term ends.
Frequently asked questions
▶What percentage of income does disability insurance typically replace?
Individual and employer long-term disability policies commonly target around 60% of pre-disability earned income, though this can range from about 50% to 75% depending on the policy and may be reduced further by other income sources.
▶Why isn't income ever replaced at 100%?
Insurers generally cap benefits below full income so there remains a financial incentive to return to work once able, which also helps keep premiums and claims costs manageable.
▶What counts as an existing monthly benefit?
Any income you would already receive during a disability without buying new coverage — employer-provided long-term disability insurance, Social Security disability benefits, or other guaranteed income.
▶What is the difference between short-term and long-term disability insurance?
Short-term disability typically covers about three to six months of a disability. Long-term disability generally starts around six months in and can last for years or until retirement age, often after short-term coverage ends.
▶Does this calculator tell me what a policy will cost or approve?
No. It estimates the monthly benefit gap based on the numbers you enter. Actual policy benefits, waiting periods and premiums are set by the insurer through underwriting.
Learn more
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Open calculator →Disclaimer: Disability Insurance Needs Calculator results are estimates for general information and education only, and are not financial, tax, legal or medical advice. Verify important decisions with a qualified professional.