The 4-step setup
Step 1 — Confirm net pay
Use your last payslip's net pay figure (not the gross). For variable income: 6-month average.
For 2026/27 reference:
| Gross | Monthly net |
|---|---|
| £25,000 | £1,818 |
| £30,000 | £2,093 |
| £40,000 | £2,565 |
| £50,000 | £3,293 |
| £60,000 | £3,772 |
| £75,000 | £4,505 |
| £100,000 | £5,522 |
Step 2 — List fixed essentials
These are predictable, must-pay-every-month bills:
- Rent or mortgage
- Council tax
- Utilities (gas, electricity, water)
- Broadband + a primary mobile contract
- Insurance (home, contents, car if needed)
- TV Licence
- Any childcare or essential services
Sum these. They should be 40–55% of net pay in a healthy budget. London + tight markets may run 55–65%.
Step 3 — List variable essentials
Costs that vary but you can't avoid:
- Groceries
- Transport (fuel + season ticket top-ups)
- Basic clothing / shoes
- Healthcare top-ups (prescriptions, dental)
- Periodic services (haircut, eye test)
Set a realistic monthly cap. Variable essentials are typically 15–25% of net pay.
Step 4 — Set discretionary + savings
What's left must split between: - Discretionary — eating out, hobbies, subscriptions, treats, non-essential shopping - Savings + investing — emergency fund, pension top-up, ISA, investing - Buffer — unallocated cushion for genuinely unexpected costs
Healthy mix: 15–25% discretionary, 10–25% savings, 5–15% buffer.
Standard template (single adult, £40,000 salary)
| Category | Monthly £ |
|---|---|
| Net pay | 2,565 |
| Fixed essentials | |
| Rent | 850 |
| Council tax | 150 |
| Utilities + broadband + mobile | 210 |
| Insurance | 35 |
| TV Licence | 14 |
| Variable essentials | |
| Food (groceries) | 280 |
| Transport (commute) | 160 |
| Personal care | 50 |
| Discretionary | |
| Eating out / takeaways | 150 |
| Subscriptions | 50 |
| Discretionary shopping | 150 |
| Savings | |
| Liquid savings | 200 |
| Pension (additional) | 100 |
| Buffer | 166 |
| Total | 2,565 |
Adjust upward or downward depending on your real costs.
Allocations by salary band
| Salary | Net/mo | Essentials | Discretionary | Savings | Buffer |
|---|---|---|---|---|---|
| £25k | £1,818 | 60–70% | 15% | 5–10% | 5% |
| £30k | £2,093 | 55–65% | 15% | 10% | 5–10% |
| £40k | £2,565 | 50–60% | 15% | 10–15% | 5–10% |
| £50k | £3,293 | 45–55% | 20% | 15% | 10% |
| £75k | £4,505 | 40–50% | 20% | 20–25% | 10% |
| £100k | £5,522 | 35–45% | 20% | 25–30% | 10% |
What kills budgets
- Forgetting annual bills — car tax, MOT, professional memberships. Amortise them.
- Underestimating variable food — most households are £80–£200/month over their stated grocery + eating out estimate.
- Subscription creep — audit recurring debits quarterly.
- No buffer line — every unexpected cost breaks the rest of the month if there's no cushion.
Review cadence
- Weekly: 5-minute glance at spend-to-date
- Monthly: 10-minute month-end review — adjust caps if categories overshot
- Quarterly: 30-minute reset — re-evaluate categories + caps against actuals
- Annually: 60-minute reset — life events, salary changes, major spending shifts
In short
A UK monthly budget needs 5 layers: net pay confirmation, fixed essentials, variable essentials, discretionary, savings + buffer. Standard guide is 50/30/20 (essentials/discretionary/savings), adjusted for housing and region. Weekly glance, monthly review, quarterly reset.