It's one of the most common conversations at the school gate, in WhatsApp groups, in quiet moments between parents who are trying to figure out whether any of this adds up. The nursery invoice arrives. You look at your salary. You do some rough maths. And suddenly the decision that felt straightforward starts to look a lot more complicated.
The question nobody has a good tool for
The basic version of the question is simple: does the second income cover what going back to work costs? But working out the actual answer is harder than it sounds, because the costs of working are spread across several different budget lines, childcare, obviously, but also the commute, the lunches you buy because you don't have time to make them, the convenience dinners on the nights you're both exhausted, the work clothes, sometimes a second car.
None of those costs appear on a payslip. None of them are labelled "cost of working." They just quietly eat into whatever the salary brings in, and most families are running these numbers informally, on gut feeling, without ever adding it all up properly.
That's what the calculator is for. But before you use it, it helps to understand the shape of the problem, because the maths has a few non-obvious features that matter a lot.
The tax problem with a second income
In most households with two earners, the first income takes up most or all of the lower tax band. The second income, the one belonging to the returning parent, often lands almost entirely in the higher band. This means a €40,000 salary doesn't generate the same take-home as it would for someone whose partner earns nothing. In Ireland, for example, a returning earner could find themselves paying 40% income tax plus USC and PRSI on most of their salary, leaving them with closer to €25,000 in hand from a €40,000 contract.
This is the part that genuinely surprises people. Not because the tax system is unfair, it's doing what it's designed to do, but because most people think in gross salary terms rather than net. The childcare invoice, however, comes out of net income. So you're paying for nursery with euros that have already been taxed at the higher rate.
What this means in practice is that the break-even salary, the gross pay at which the second income stops costing your household money, is often higher than people expect. The calculator works this out for you, backwards from your costs, and shows you the gross figure you'd need to earn for the arrangement to pay for itself.
The costs that people forget to count
Childcare is the obvious one, and it's enormous. In Ireland, a full-time nursery place for a child under one costs between €1,200 and €2,000 a month depending on where you live. For two children, you're looking at costs that can reach €3,500 or €4,000 before any other expenses appear.
But here's the rest of the list that often doesn't make it into the mental calculation:
The second commute. If you were on parental leave and your partner was commuting, you had one commute cost. Now you have two. That's not insignificant.
The convenience food penalty. When both parents are working full-time with young children, nobody has the energy to cook from scratch every night. The grocery bill shifts toward convenience food, and there are more takeaways. This is not a moral failure, it's a practical reality of having no time. But it's a real cost, somewhere between €150 and €400 a month for many families, and it only exists because both adults are working.
The drop-off logistics. If neither parent can do the school or nursery run at a convenient time, you sometimes need to pay someone who can. This gets folded into the childcare bill sometimes, but often it's an additional cost on top.
Work clothing. This one's small, but it's real. If you spent a year in leggings and jumpers and now you need a professional wardrobe again, that costs money.
The sick child problem. Children in nursery get ill constantly. When that happens, one parent typically needs to take a day or half-day off work. This isn't a financial cost directly, but it's a source of stress and disruption that has an indirect cost, in goodwill with employers, in workload buildup, in the mental load of managing it.
A worked example
Sarah is returning to work after maternity leave. Her gross salary is €38,000. Her partner earns €52,000. They have one child going into a crèche that costs €1,350 a month. Sarah's commute costs €35 a week in fuel. They estimate they spend about €200 a month more on food than they did before both working. Sarah's tax rate, given her partner's salary, is approximately 40% plus USC and PRSI, so her effective deduction rate is around 52%.
Her take-home pay: €38,000 × (1 − 0.52) = €18,240 a year, or €1,520 a month.
Her childcare cost: €1,350 per month.
Her commute cost: €35 × 47 weeks ÷ 12 = €137 per month.
Her food premium: €200 per month.
Total working costs: €1,687 per month.
Monthly surplus: €1,520 − €1,687 = −€167 a month.
On these numbers, Sarah's job costs her household €167 a month to hold down. The break-even salary, the gross she'd need to earn for the arrangement to pay for itself, is around €42,500.
That's not a verdict. It might be worth it for career continuity, for pension, for the seniority she'd lose by stepping back, for her own mental health and sense of identity. But it's a real number, and it deserves to be known rather than guessed at.
The one-year view versus the ten-year view
Here's the honest version of the longer-term picture. Childcare costs are brutal for roughly three years for one child, and potentially six or seven if you have two. After that, they fall dramatically, school is free, after-school care is a fraction of nursery fees. The salary that costs you money in year one starts generating a meaningful surplus by year four or five.
The salary you walk away from, however, tends not to come back at the same level. Gaps in CVs are real. The promotions that happened while you were out didn't happen to you. The pension contributions that weren't made don't compound. These are not sentimental considerations, they're financial ones, and they run in the opposite direction to the childcare bill.
The calculator gives you the monthly figure. The ten-year view requires you to think about what stepping back genuinely costs in the long run. For most people, holding on through the expensive years is the better financial decision across a working lifetime, even when the monthly numbers say otherwise. But that's a decision for you to make with real numbers in front of you, not a guess.
What about childcare subsidies and supports?
In Ireland, the National Childcare Scheme (NCS) provides subsidies based on household income, and the free ECCE preschool year provides 15 hours a week of free childcare once a child turns 2 years and 8 months. These reduce the effective cost significantly and are worth factoring into your numbers. The calculator has a field for childcare support, enter your monthly subsidy there. If you're not sure what you're entitled to, check citizensinformation.ie, which has a clear breakdown of the NCS income thresholds.
In the UK, 30 hours of free childcare is available for working parents of 3 and 4 year olds. In the US, the Dependent Care FSA allows you to pay for childcare with pre-tax dollars, reducing the effective cost. Every country has its own regime, and the calculator is designed to take your actual net childcare cost as an input, so whatever support you receive, enter what you actually pay after it.
Put your own numbers in and find out exactly where you stand, including the salary you'd need to break even.
Calculate whether going back is worth it →Frequently asked questions
What if we have two children in childcare?
Enter the number of children in paid care and the average cost per child per month. The calculator scales the childcare cost across both children, minus any free days covered by family. With two children under three in full-time care, many families find the break-even salary exceeds what either parent earns, which is worth knowing, because it changes the conversation about hours and working patterns.
Should I include the pension I'm missing out on?
The calculator deliberately excludes pension and career progression, not because they don't matter, but because including them would flatter the result in one direction and you'd end up making decisions based on projected future value rather than actual current cash flow. Think of the monthly surplus or deficit as the real short-term picture. The pension and career arguments belong in a separate, longer-term consideration.
My partner earns more than me. Does that change the maths?
Yes, potentially significantly. Because your salary stacks on top of your partner's, you'll pay the marginal tax rate on most of what you earn. The key input is your effective combined deduction rate, look at what percentage of your gross actually disappears in tax, USC, PRSI and pension, and use that number. It's often between 45% and 55% for a second earner in a dual-income Irish household.
What if I could work part-time instead?
Run the calculator twice, once at full-time hours and salary, once at part-time. Part-time work usually means proportionally lower childcare costs (fewer days needed), a lower commute cost, and a lower convenience food premium. For many families, three or four days a week produces a better surplus than five, even at a lower gross salary, because the cost savings are nearly as large as the income reduction.
Is it worth it even if the numbers say no?
Possibly, for non-financial reasons. Career continuity, professional identity, workplace relationships, your own mental health and sense of purpose, these are real and they matter. The calculator gives you the financial picture. What you do with it is yours to decide. Plenty of people choose to work at a monthly net cost because the non-financial value is real enough to justify it. Knowing the cost makes that a genuine choice rather than a discovery.
We're getting grandparent help some days. How do I account for that?
Use the "days per week covered free" field. If your parents take the children on Mondays and Fridays, that's two free days, and the calculator reduces the effective childcare cost proportionally. Family help is genuinely part of the financial picture and deserves to be counted.
What about employer-provided childcare or salary sacrifice schemes?
Enter the monthly value of any employer childcare support in the "support and subsidies" field. In the UK, some employers offer childcare voucher or salary sacrifice arrangements, enter the monthly saving those generate. The calculator treats all childcare support the same way: it reduces the effective childcare cost before working out your surplus.