Going back 3, 4 or 5 days: what changes financially?
Three days, four days, five days. The salary difference is easy to picture. What you'll have left each month is not.
The useful comparison is what each extra day adds once the extra costs and deductions are taken off. It won't be the same amount for every extra day.
First, compare hours, not day labels
If five equal days pay £50,000, three days at the same daily hours pay £30,000 and four pay £40,000, assuming your salary is cut pro rata. Four compressed days holding full-time hours is a different deal.
Confirm the actual salary and the actual childcare sessions before you calculate anything. A day count doesn't tell you either.
A worked example, with the assumptions on show
This is an example. It's not typical childcare pricing and it's not a forecast of anyone's payslip.
Assume a full-time salary of £50,000, cut pro rata for three or four equal days. Use 2026/27 Income Tax rates for England, Wales and Northern Ireland, the full £12,570 Personal Allowance, and standard employee National Insurance worked out on the monthly threshold. Assume a 5% employee pension contribution on the whole salary through a net-pay arrangement, where the employer takes the contribution out of pay before Income Tax (not salary sacrifice), plus 5% from the employer. No student loan, no other income, no benefits, no other deductions. HMRC: Income Tax rates and allowances, HMRC: Rates and thresholds for employers 2026 to 2027, GOV.UK: Workplace pensions, What you, your employer and the government pay, GOV.UK: Tax on your private pension, Pension tax relief.
The calculation assumes a steady full year at each salary, with tax spread evenly across twelve months. It won't match your payslip if you return mid-year. Payroll rounding can also differ.
For childcare, assume the family has worked out its final out-of-pocket cost after all support as £600, £800 and £1,100 a month. These are invented inputs. No further childcare subsidy is taken off below.
Monthly unless stated; rounded to the nearest pound | 3 days | 4 days | 5 days |
|---|---|---|---|
Annual gross salary | £30,000 | £40,000 | £50,000 |
Estimated monthly take-home | £1,993 | £2,560 | £3,127 |
Childcare paid by the household | £600 | £800 | £1,100 |
Extra work costs | £90 | £120 | £150 |
Pay left after those costs | £1,303 | £1,640 | £1,877 |
This isn't spare money after all the bills. Housing, food and the rest still come out of it. And showing childcare next to one salary doesn't make it that person's cost alone.
What does each extra day add?
Using unrounded figures, going from three days to four adds about £567 in take-home pay, less £200 more childcare and £30 more work costs. Net gain: about £337 a month.
Going from four days to five adds roughly the same take-home, but childcare goes up by £300 rather than £200. Net gain: about £237 a month.
That difference comes from the inputs, not from a rule that a fifth day is worth less. A different nursery bill, family help or a different work pattern could flip it.
If you pay Scottish Income Tax, the bands are different, so your take-home and the gain from each extra day change too: on these assumptions, the fifth day adds about £162 a month. HMRC: Income Tax in Scotland.
Show pension contributions separately
With 5% from the employer on the whole salary, annual employer contributions would be £1,500, £2,000 and £2,500. Your gross contributions would be the same.
So in this example, each extra day adds £500 a year from your employer and £500 from you. That's retirement saving, not cash to add to the monthly figure. Other schemes use qualifying earnings or different pensionable-pay rules. GOV.UK: Workplace pensions, What you, your employer and the government pay.
What could change your own answer?
Student loans. Repayments depend on your earnings above the threshold for the pay period, so a change in hours changes them. GOV.UK: Repaying your student loan, How much you repay.
Benefits. Universal Credit moves with household earnings. If you leave an existing UC award unchanged across every scenario, the comparison can be badly wrong. DWP: Universal Credit, How your wages affect your payments. You also can't get Tax-Free Childcare at the same time as Universal Credit. HMRC: Tax-Free Childcare, Check if you’re eligible.
Childcare eligibility. Some schemes have minimum-earnings tests and individual upper-income limits. Tax-Free Childcare and England's working-parent offer generally exclude families where either parent expects adjusted net income over £100,000, subject to their rules. Test each scenario with the right income definition. HMRC: Tax-Free Childcare, Check if you’re eligible, GOV.UK: Free Childcare for Working Parents, Check if you’re eligible. Free Childcare for Working Parents is for families in England. Scotland, Wales and Northern Ireland have different funded childcare schemes. GOV.UK: Free Childcare for Working Parents, Overview.
Timing. A quote that includes funded hours may not cover your first months back. Compare the first year, not just the cheapest month. GOV.UK: Free Childcare for Working Parents, When to apply.
Use the numbers to ask a better question
Once the cash difference is clear, think about what each pattern means for your family's time, care needs and work plans. Those aren't errors in the spreadsheet. They're the decision.
A good comparison shows both the extra cash and the extra commitments. It doesn't pin a "best parent" badge on any pattern.
