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FinToolSuite
Updated April 20, 2026 · B2B Insurance · Educational use only ·

Critical Illness Cover Calculator

Critical illness cover size.

Calculate critical illness cover needed based on essential expenses, recovery period, mortgage balance, and other outstanding debts.

What this tool does

This calculator estimates the total critical illness cover amount by combining three financial elements: living expenses during recovery, outstanding mortgage balance, and other existing debts. It multiplies your monthly essential expenses by the recovery period you specify to determine income replacement needed, then adds any mortgage and debt balances to calculate a combined cover figure. The result represents the lump sum that would theoretically cover ongoing household costs, debt repayment, and other obligations if a critical illness prevented income during your stated recovery timeframe. The calculation assumes expenses remain constant and does not account for income from other sources, investment growth, existing savings, or changes in circumstances. This tool provides an educational illustration of how these factors interact—actual cover needs depend on personal circumstances and should be assessed individually.


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Formula Used
Monthly expenses
Recovery months
Mortgage
Other debts

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Disclaimer

Results are estimates for educational purposes only. They do not constitute financial advice. Consult a qualified professional before making financial decisions.

Critical illness cover pays a tax-free lump sum on diagnosis of listed conditions (cancer, heart attack, stroke typically top the list). This calculator sizes cover need: monthly essential expenses × recovery period (typically 24 months for most illnesses) + mortgage payoff + other debts. The idea is one-time payout replaces income and clears fixed obligations during recovery.

3,500 monthly expenses × 24 months = 84,000 income replacement. 250,000 mortgage + 10,000 other debts = 344,000 total cover. Costs a non-smoker 35-year-old approximately 25-50/month for 25-year level term policy. Cost rises sharply with age: 55-year-olds pay 4-6x premium for same cover.

Critical illness vs income protection. Critical illness: lump sum, specific conditions only, pays once. Income protection: monthly payments for any illness keeping you from work, pays until return to work. Most people benefit from both - critical illness for mortgage clearance on major diagnoses, income protection for income replacement on any illness.

Quick example

With monthly essential expenses of 3,500 and recovery period of 24 months (plus mortgage balance of 250,000 and other debts of 10,000), the result is 344,000.00. Change any figure and watch the output shift — it's often more useful to see the pattern than to memorise the formula.

Which inputs matter most

You enter Monthly Essential Expenses, Recovery Period (months), Mortgage Balance, and Other Debts. Not every input has equal weight. Adjusting one input at a time toward extreme values shows which ones move the result most.

What's happening under the hood

Income replacement = expenses × months. Total cover = income + mortgage + other debts. The formula is listed in full below. If the number looks off, you can retrace the calculation by hand — that's the point of showing the working.

What the score tells you

Headline financial numbers — income, savings, debt — each tell part of the story. This calculation stitches several together into a single read you can track over time. The value is in the direction, not the absolute number.

What this doesn't capture

The score is a composite of the inputs you provide. Life context — job security, family obligations, health, housing — doesn't appear in the math but shapes the real picture. Use the number as a prompt, not a verdict.

Example Scenario

££3,500 × 24mo + ££250,000 mortgage + ££10,000 = 344,000.00.

Inputs

Monthly Essential Expenses:£3,500
Recovery Period (months):24
Mortgage Balance:£250,000
Other Debts:£10,000
Expected Result344,000.00

This example uses typical values for illustration. Adjust the inputs above to match a specific situation and see how the result changes.

Sources & Methodology

Methodology

The calculator computes the recommended critical illness cover amount by combining three components. First, it multiplies your monthly essential expenses by the recovery period in months to model income replacement during the time needed to return to work or resume normal activities. Second, it adds your current mortgage balance to account for ongoing housing obligations. Third, it includes any other outstanding debts. The model assumes expenses remain constant throughout the recovery period and treats all debts as due in full. It does not account for existing savings, investment returns, changes in living costs, redundancy protection, other income sources, or variations in recovery timelines.

Frequently Asked Questions

Which conditions are covered?
Standard policies cover 40-70 conditions. Core: cancer (all types at advanced stages), heart attack, stroke, multiple sclerosis, Parkinson's, kidney failure. Premium policies add more conditions - always read the policy documents carefully.
How much does it cost?
35-year-old non-smoker: 20-50/month for 300k cover over 25 years. Age 45: 50-100/month. Age 55: 150-300/month. Smokers pay 2-3x. Family history of covered conditions can also raise premiums.
Is there any payout for minor conditions?
Some policies have 'partial payout' options - e.g., 25% of sum insured for early-stage cancers that would not qualify for full claim. relevant as cost adds only 10-20% to premium.
When to buy CI cover?
Younger = cheaper, easier underwriting. Ideal window is 25-40. Buying in 50s becomes expensive and medical questionnaires get detailed - if you've ever been investigated for chest pain or had a biopsy, cover gets harder to obtain.

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