When arranging term life insurance, one of the first structural decisions is whether the sum assured should remain constant throughout the policy term (level term) or reduce over time (decreasing term). This choice has a material impact on cost, suitability, and the adequacy of cover when a claim is made.
The decision sounds straightforward but is regularly mishandled — especially by people who choose decreasing term primarily on cost grounds without properly understanding whether a reducing sum assured matches their actual liability. This guide walks through both structures systematically and explains the scenarios in which each is appropriate.
This is general information only. Insurance availability, costs, and tax rules differ by jurisdiction and individual circumstances. You should take qualified financial advice before arranging or amending any protection policy.
The Fundamental Difference
Level term: the sum assured is fixed from inception to expiry. A £400,000 policy arranged today pays £400,000 whether you die in year one or year 24 of a 25-year term.
Decreasing term: the sum assured reduces over time, typically — but not always — following a schedule that mirrors a specific reducing liability. In the standard mortgage protection version, the sum assured reduces monthly in rough alignment with a capital repayment mortgage balance.
Because the insurer's maximum exposure decreases each year in a decreasing term policy, the insurance risk is concentrated at the start of the term and diminishes over time. Premiums are correspondingly lower than level term for the same initial sum assured.
When Level Term is Appropriate
1. Family Income Replacement — Non-Mortgage Liabilities
The death of a breadwinner (or of a primary carer whose contribution must be replaced) creates an income gap that may persist for many years — potentially until children are grown and financially independent. The household's ongoing costs (food, utilities, education, rent or mortgage, childcare) do not reduce because a family member has died.
A level sum assured ensures the surviving family has access to a capital sum large enough to generate replacement income, or to fund a family income benefit arrangement, at any point during the term. Decreasing term would leave progressively less capital available in later years even though the income need remains constant.
For income replacement purposes, level term should be the default.
2. Interest-Only Mortgages
On an interest-only mortgage, the outstanding capital balance does not reduce during the mortgage term — only the interest is paid. If the policyholder dies, the full capital sum is still owed to the lender.
Decreasing term insurance is designed around a capital repayment schedule. Applying it to an interest-only mortgage means the sum assured reduces while the debt does not — creating an increasingly large shortfall as the term progresses. Level term is the correct structure here.
3. Business Loan Protection on Interest-Only Facilities
Many commercial loans and business overdraft facilities are structured on an interest-only or revolving credit basis, with the capital repayable in full at maturity or on demand. Level term matches the liability profile correctly. A decreasing term policy would steadily underinsure the business.
4. Inheritance Tax (IHT) Planning
Level term policies written in trust and used as part of an IHT strategy — for example, to cover the tax liability on a 7-year potentially exempt transfer (PET) — need to provide the same sum assured throughout the term, since the underlying gift does not reduce below its full value until the full 7-year survival period has elapsed (tapering relief notwithstanding). Level term is the appropriate vehicle.
5. General Capital Provision
Where the objective is to leave a specific capital sum to dependants or to fund a defined liability that does not reduce — education costs, a legacy, a business buyout obligation — level term is appropriate.
When Decreasing Term is Appropriate
1. Capital Repayment Mortgage Protection
This is the primary use case for decreasing term insurance. With a capital repayment mortgage, each monthly payment reduces the outstanding balance. The insurance need reduces in parallel. A decreasing term policy is designed to track this reducing balance and, if the policyholder dies, pay enough to clear the remaining mortgage.
It is cheaper than level term for the same initial sum assured because the insurer's risk reduces steadily over the term.
Important caveat: the reduction schedule built into the insurance policy is based on an assumed interest rate (typically 6-8%). Your actual mortgage balance may differ due to:
- Rate changes on variable or tracker mortgages
- Overpayments or underpayments
- Payment holidays
- Remortgaging or product switches
Where mortgage rates are materially below the assumed policy rate, the mortgage balance will reduce faster than the policy sum assured, meaning the policy likely provides a small surplus. Where mortgage rates are higher (or if capital repayments slow), there can be an undershoot. Periodic reviews help ensure adequacy.
2. Business Loans with Reducing Capital Balances
Where a business loan is structured with monthly capital repayments (a term loan), decreasing term insurance linked to that repayment schedule can be a cost-effective way to cover the liability. The key is to review the policy whenever the loan terms change — for example, if the loan is refinanced or extended.
3. Personal Loans and Hire Purchase
For individuals with significant personal loan or hire purchase obligations — where the outstanding balance reduces monthly — decreasing term provides targeted cover at lower cost than level term.
Cost Comparison
The premium differential between level and decreasing term varies with age, health, term length, and the sum assured, but as a general illustration:
For a healthy, non-smoking 35-year-old arranging £300,000 of cover over 25 years, decreasing term might cost in the region of 30-40% less per month than level term from a comparable insurer. Actual quotations vary substantially — comparison is always necessary.
This cost difference is meaningful but should not be the primary selection criterion. Choosing decreasing term to protect an interest-only mortgage or a family income need is a false economy that creates a protection gap.
Critical Illness Rider Options
Both level and decreasing term policies can be combined with a critical illness rider, which adds a payment on diagnosis of specified serious conditions (most commonly cancer at a qualifying stage, heart attack, stroke, and a defined list of other conditions).
With a level term + CI rider: the sum assured remains constant. A diagnosis in year 15 of a 25-year policy pays the same amount as a diagnosis in year 2.
With a decreasing term + CI rider: the sum assured at the time of diagnosis reflects the reduced balance. In the later years of the term, this may be considerably less than the original sum assured — which may or may not reflect the remaining liability. If the mortgage is almost cleared, a smaller payout may be adequate. But if the critical illness rider is also meant to provide funds for adaptation costs, loss of earnings, or treatment costs, the reduced sum may be insufficient.
For clients who want critical illness cover to serve a purpose beyond mortgage clearance (income replacement during illness, home adaptation, private treatment costs), a standalone critical illness policy or a level term + CI combination is generally more suitable.
Mixing the Two Structures
A common planning approach is to use a combination:
- Decreasing term to cover the capital repayment mortgage balance (the cheapest structure for that specific liability).
- Level term to cover income replacement and family living costs.
This separates the mortgage liability from the income protection need, allows each policy to be sized appropriately, and can be cost-efficient overall. The two policies can each be written in trust separately, and if the mortgage is paid off early, the decreasing term policy can be cancelled without affecting the level term cover.
Joint Life and Separate Policy Considerations
Both level and decreasing term policies are available on a joint life first death basis or as separate single-life policies. The structural considerations are the same for both:
- Joint life pays once (on the first death) and then lapses, leaving the surviving partner uninsured.
- Two separate policies cost more in aggregate but provide continued cover for both lives.
For mortgage protection, a joint life decreasing term policy is commonly used — the rationale being that the mortgage is a joint liability and the priority is to clear it on either death. However, separate policies provide more flexibility, especially if the relationship ends or if separate income replacement needs exist.
Guaranteed and Reviewable Premiums
Both level and decreasing term policies are available with guaranteed premiums (fixed for the term) or reviewable premiums (subject to periodic revision by the insurer). For the reasons explained in the term assurance guide on this site, guaranteed premiums are generally preferable unless there is a specific reason to accept review risk.
Common Mistakes
- Using decreasing term for an interest-only mortgage: this is one of the most common and consequential errors in mortgage protection. Always match the policy structure to the mortgage type.
- Underestimating the income replacement need: clearing the mortgage does not cover school fees, childcare, household bills, or the non-financial contributions of a non-earning partner.
- Allowing the policy to run to term without review: mortgage overpayments, remortgages, or changes in family circumstances change the protection requirement.
- Ignoring the critical illness rider adequacy question: a small CI payout late in a decreasing term policy may not meet the real cost of a critical illness.
How Global Investments Can Help
Global Investments advises high-net-worth individuals, business owners, and internationally mobile clients on the full range of protection planning — from straightforward mortgage cover to complex multi-policy structures spanning several jurisdictions.
Our advisers can model your protection requirements, compare available structures across leading UK and international insurers, and ensure that the policies you put in place are correctly matched to your liabilities and financial objectives. We review our clients' protection arrangements regularly so that cover remains appropriate as circumstances change.
If you would like a protection review or a comparison of level and decreasing term options for your situation, please contact us to arrange a consultation.
This guide reflects UK insurance market practice and rules as at June 2026. Tax treatment and product availability vary by jurisdiction. This article is for general information only and does not constitute regulated financial advice. Always seek independent professional advice before arranging or amending any insurance policy.
This guide is for general information only and does not constitute financial or insurance advice. Policy terms, premium rates, and insurer eligibility criteria change — always verify current terms with a qualified independent adviser before taking out any policy.