London newlyweds: rent vs buy with kids

A side-by-side plan for 1 vs 2 children, childcare years, and the tradeoff between staying renters and buying in 2028.

In London, your 30s often come with three expensive plot twists at once: a bigger place, childcare, and the question you can’t quite ignore forever - “should we buy?” This scenario turns that messy decade into a few clean timelines you can compare side by side.

This example follows a newly married dual-income couple (both 30, no kids yet) who start in 2026 with £30,000 saved, aim to retire at 68, and plan through age 90.

Who this scenario is for

This scenario is a good fit if you:

• Live in London (or Greater London) and are planning your first child soon
• Earn a combined £80k-£150k gross, which is a realistic range for two London professionals, with roughly 60-70% net take-home after tax and pension
• Expect to move from a 1-bed to a 2-bed, and possibly a 3-bed later
• Want to understand how childcare and housing costs reshape your net monthly room to invest
• Are deciding between staying renters vs trying to buy (with a big one-off deposit)
• Already contribute to pensions/ISAs and want to stress-test the next 10-15 years

Your starting point

• Ages: 30 now
• Start date: January 2026
• Retirement plan: retire at 68, plan to 90
• Starting savings: £30,000
• Retirement baseline: a full-couple UK State Pension
• Retirement lifestyles shown: from a cautious mid-£4k monthly lifestyle to a more ambitious low-£6k plan, while sustainable monthly spending lands around £3.9k-£5.6k/month

Note on the money: the £ amounts are shown in today’s money, so read them as inflation-adjusted buying power rather than future sticker prices.

What the numbers show

All five versions keep investable savings above zero through age 90, though the strongest-return rent case finishes with the thinnest cushion after later-life family support and care costs. The retirement budgets shown here are deliberately a little more ambitious than the conservative range, so you can see what happens if you spend more of the cushion instead of leaving a large balance unused.

Compound growth is still back-loaded. In the Base · Rent + 1 child path, interest generated in each decade looks like:

• 30-39: ~£17,800
• 40-49: ~£35,700
• 50-59: ~£84,000
• 60-67: ~£129,900

By the time you reach your 60s, one decade of compounding adds more growth than the first two decades combined—which is why keeping cashflow positive through the childcare years matters so much.

What this comparison evaluates

This comparison is built to answer three practical questions:

• If you plan for one child soon (rent variants assume a 2028 birth), how do childcare and housing costs change the net money left over for your goals?
• What changes if you plan two children (second arriving in 2031) plus a later move to a 3-bed?
• If you buy in 2028 and delay having a child until 2030, how do the one-off costs and the higher ongoing housing costs affect the long-run cushion?

How the costs are planned

Each version starts from the same broad household profile and then changes only the pressures that matter most: a larger home, childcare in the early years, and how much room is left for saving once those costs peak.

• The renting paths assume the couple moves up in home size as children arrive, with the two-child version eventually needing more space again.
• The buying path swaps part of that rent pressure for a large upfront purchase cost and a period of higher monthly housing costs.
• Childcare is shown as an estimated out-of-pocket cost after typical support, not as a promise of exact benefit eligibility.
• Later-life family support and care costs are included so the plan does not end with an unrealistically large untouched pot.

If your situation differs, use the guide to changing costs and timing to adjust the childcare years, move date, or one-off family support before using this scenario for a real decision.

The strategy

Your active years (30 to retirement)

Think of these timelines as a plan for protecting savings through the years when family costs rise fastest. Every version assumes the couple keeps investing through adulthood, but with much less room to maneuver when housing and childcare costs peak.

• Rent + 1 child: This path assumes the couple builds a modest cash buffer before the first birth, moves to a larger rental when family life starts, and sees the biggest squeeze during the nursery years. Savings recover once childcare eases, so the long-run outcome depends less on one perfect year and more on keeping contributions going through the expensive early-parenthood stretch.
• Rent + 2 kids: This version assumes stronger earnings, a second step up in housing, and a longer period of childcare pressure. It can still work, but the family has less room for mistakes in the mid-30s because two childcare windows and a bigger home absorb more of the surplus that would otherwise compound.
• Buy + 1 child (later): This path brings forward the hardest cash decision by prioritizing a deposit and higher housing costs before the first child arrives. That usually means less flexibility early on, but more housing security and a slightly stronger long-run asset position if the couple can get through the first few years without breaking their savings habit.

Across every path, childcare support and later family costs should be treated as planning ranges rather than exact entitlements. If your borough, hours, or eligibility differ, adjust those costs in the scenario before using it for a real decision.

Your retirement years (68 to 90)

Every variant assumes both partners reach a full-couple UK State Pension baseline and then draw from investments to cover the retirement lifestyle you pick:

• The lower-return rent case still supports a mid-£4k monthly retirement budget, but with a thin late-life buffer.
• The central cases cluster around roughly £5k/month, which is workable but leaves limited slack by age 90.
• The strongest-return case can stretch into the low-£6k/month range, but only if long-run returns stay very favorable.
• The buy-first case lands in the high-£4k/month range and also leaves home equity outside the investable total.

Those later-life costs, especially university help and eldercare, are the main reason these versions do not finish with a large unused balance. Reduce them if you expect to give less support, or increase them if you want to test a more generous family plan.

Personalize it to your real life

When you open the scenario, start from the version that feels closest to your life, then try these edits first:

• Saving pace + temporary cushion: raise or lower the regular saving pace before and after children arrive. If one phase of family life looks tighter in your household, shorten the extra-saving window or pause it for a while.
• Childcare + support: move the expensive years forward or backward, shorten them if family help is realistic, or lower the expected support if your eligibility is uncertain. Funded-hours guidance changes frequently, so verify the latest GOV.UK rules when you edit.
• Housing costs: change the timing or size of the move, swap in borough-level rent or ownership costs, or push the purchase later if rates or deposit progress make that more realistic.
• Family support later on: adjust how much help you expect to give with university, a future housing boost, or care later in life if you want a larger or smaller end-of-life cushion.
• Retirement budget + returns: compare a cautious, middle, and optimistic return path, then match the retirement budget to the sustainable monthly spending figure in the table if you want a steadier long-run plan.

A note on UK childcare rules

To keep the versions comparable, childcare is shown as one estimated out-of-pocket cost after typical support rather than a full rules-by-rules calculation.

• Childcare support in England can include funded hours, Tax-Free Childcare, and Child Benefit. At this income level, support can reduce childcare costs, but the exact mix depends on current rules, hours used, and each partner’s adjusted net income. Treat this page as a planning range, then verify the latest GOV.UK guidance before making decisions.
• If you might qualify for means-tested support (edge cases), the true net cost can look very different—use the scenario to set a range, then verify against up-to-date guidance on GOV.UK before making decisions.

Start planning from the decisions that actually bite

If you’re trying to decide “should we have a second child?” or “should we stretch to buy?”, this scenario helps you convert those questions into two things you can act on:

• A realistic savings pace to target (and how pausing contributions or pushing a purchase changes the long-run cushion)
• A sense of the retirement cushion you’re likely to build—plus the sustainable monthly spending figure in the table if you want a bigger end-of-life margin

Need a child-free rent-vs-buy check instead? Compare this scenario with London couple (32): rent forever or buy by 35? to see how removing childcare shifts the timeline.

This is a scenario-planning example, not financial advice. It simplifies taxes, childcare eligibility, and housing choices into planning assumptions so you can test trade-offs.