Mirror will vs Single will: Which one do you need?

If you have ever searched for information about getting a will, you have probably encountered the terms ‘single will’ and ‘mirror will’ without a particularly clear explanation of what they mean or which one you need. This article clears that up – in plain English, with no legal jargon – so you can make a confident decision for your family.

The short version: a single will is for one person. Mirror wills are for couples who want to leave their estates to each other. But as with most things in estate planning, the detail matters – and getting this decision right now can prevent significant complications later.

What is a single will?

A single will is a legal document written for one individual. It sets out what you want to happen to your estate – your property, savings, possessions, and anything else you own – when you die. It names the people or organisations you want to benefit, known as your beneficiaries. It names the person you want to manage and administer your estate, known as your executor. And if you have children under 18, it names the person or people you want to act as their guardian.

A single will is appropriate when:

• You are not in a relationship, or you want your will to reflect your individual circumstances rather than a shared arrangement.
• You and your partner have meaningfully different wishes about what should happen to your respective estates.
• You are in a blended family situation and want to ensure that children from different relationships are specifically provided for.
• You have significant individual assets – property in your sole name, a business interest, or a specific inheritance – that you want to deal with independently.

What are mirror wills?

Mirror wills are two separate wills – one for each partner – that reflect the same core wishes. The most common structure is simple: each partner leaves their entire estate to the other, and if the other has already died, the estate passes to the same named beneficiaries – typically the children.

They are called mirror wills because they mirror each other. They are not a single document shared by both partners. Each will is a fully valid, legally independent document. If one partner dies, their will is administered as a standalone document. The survivor’s will remains in full effect until they die.

Mirror wills are typically right for couples who:

• Are married, in a civil partnership, or in a long-term committed relationship.
• Have the same wishes about who should benefit from the estate – typically each other first, and then children.
• Own assets jointly and want to ensure a clean, simple transfer to the surviving partner.
• Have not yet accumulated complex estate planning needs such as trusts, business succession planning, or inheritance tax mitigation.

The key differences between single and mirror wills

The practical differences between single and mirror will come down to three things: structure, cost, and purpose.

Structure

A single will reflects one person’s individual wishes entirely. Mirror wills are designed as a complementary pair and are typically drafted together by a professional who can ensure they align correctly and do not create unintended gaps or contradictions.

Cost

At Versatile Wills, a single will is priced at £150. Mirror wills for a couple are priced at £300 – which represents significantly better value than paying for two individual wills, and ensures the documents are professionally aligned.

Purpose

A single will is entirely focused on what one person wants. Mirror wills are designed to protect a couple’s shared estate planning intentions – ensuring that whichever partner dies first, the outcome is the same.

Can mirror wills be changed after one partner dies?

This is one of the most important and frequently misunderstood aspects of mirror wills. Because each will is a separate, independent document, each partner is technically free to change their will at any time – including after the other partner has died.

This becomes relevant in situations such as remarriage after bereavement. If your partner dies and leaves everything to you under their mirror will, and you subsequently remarry, you could in principle change your own will to leave everything to your new spouse – potentially disinheriting children from the first relationship entirely.

If this is a concern, it is worth discussing a ‘mutual wills’ arrangement or a discretionary trust structure with your will writer. These are more complex arrangements, but they can provide greater certainty in blended family or second marriage situations. A STEP-qualified professional can advise you on whether this level of protection is appropriate for your circumstances.

What about unmarried couples?

Mirror wills are especially important for unmarried couples. As explained in our guide to what happens if you die without a will, an unmarried partner has no automatic right to inherit anything under the intestacy rules. Mirror wills directly address this by legally expressing each partner’s wish to leave their estate to the other.

However, mirror wills alone are not always sufficient for unmarried couples with shared property. It is worth reviewing how your property is held – as joint tenants or tenants in common – and whether additional arrangements, such as a Declaration of Trust, are needed to fully protect your partner’s position.

Do I need separate wills if we have children from previous relationships?

If either or both partners have children from previous relationships, mirror wills require careful drafting. A standard mirror will that leaves everything to the surviving partner first can have unintended consequences: if your partner outlives you and then changes their will, your children from a previous relationship may receive nothing.

This is a situation where professional advice genuinely matters. A STEP-qualified will writer can help you structure your wills to protect both your partner’s security and your children’s inheritance – often through a life interest trust or similar arrangement.

Making the right decision

For most straightforward couples – married or unmarried, with or without children from this relationship only – mirror wills are the right choice. They are cost-effective, professionally aligned, and provide a clear, legally robust framework for both partners.

For couples with more complex circumstances – second marriages, blended families, significant individual assets, or inheritance tax considerations – a conversation with a STEP-qualified professional will help you understand whether mirror wills are sufficient or whether additional structures are needed.

Learn more about our will writing service , or if you are ready to get started, book a free consultation today. Your will can be completed within five working days.