Budget Surplus Calculator United Kingdom 2026-27
Your monthly surplus or deficit from income and expenses, the savings rate it implies, how long an emergency fund takes to build, and when a savings goal arrives — with or without an investment return.
Surplus = income (including any secondary income) − expenses; the savings rate is the surplus as a share of income.
| Income | £6,500.00 |
|---|---|
| Expenses | £5,200.00 |
How the budget surplus works
Surplus = income (including any secondary income) − expenses; the savings rate is the surplus as a share of income. The emergency target is the months of expenses you choose, reached in target ÷ surplus months. A savings goal is goal ÷ surplus months, or fewer when the surplus earns a return (the annuity formula). The projections compound the monthly surplus at the return over one, five and ten years.
Formula: Surplus = income − expenses · rate = surplus ÷ income · emergency months = ⌈months × expenses ÷ surplus⌉ · FV = surplus × ((1 + r)ⁿ − 1) ÷ r
How the Budget Surplus Calculator works
What is a budget surplus or deficit?
A budget surplus occurs when your income exceeds your expenses — you have money left over at the end of the month. A budget deficit means you are spending more than you earn. This calculator subtracts your total monthly expenses from your net monthly income and shows both the dollar amount and percentage of income remaining.
Net income vs gross income
Always use your net (after-tax) income — the amount that actually arrives in your bank account. Your gross salary is higher than your take-home pay due to income tax, National Insurance, Student Loan repayments, and pension. Use the Pay Rise to find your exact net income.
| Gross salary | Net monthly income (approx) | After Plan 2 student loan |
|---|---|---|
| £60,000 | £3,780 | £3,550 |
| £80,000 | £4,746 | £4,367 |
| £100,000 | £5,713 | £5,184 |
| £120,000 | £6,346 | £5,666 |
Budget surplus examples by income and lifestyle — 2026-27
These examples show typical surplus/deficit scenarios for UK households.
| Situation | Net income/month | Expenses/month | Surplus | % saved |
|---|---|---|---|---|
| Single renter, £70k salary | £4,558 | £3,200 | £1,358 | 29.8% |
| Single owner, £85k salary | £5,350 | £4,100 | £1,250 | 23.4% |
| Couple, £140k combined | £9,100 | £6,500 | £2,600 | 28.6% |
| Family of 4, £150k combined | £9,600 | £8,200 | £1,400 | 14.6% |
| Single renter, £50k salary | £3,442 | £3,600 | -£158 | Deficit |
The 50/30/20 rule — a proven budget framework
What is the 50/30/20 rule?
The 50/30/20 rule divides your after-tax income into three categories: 50% for needs (rent/mortgage, groceries, utilities, transport, insurance), 30% for wants (dining out, entertainment, subscriptions, holidays), and 20% for savings and debt repayment.
Applying it to UK incomes
| Net income/month | 50% Needs | 30% Wants | 20% Savings |
|---|---|---|---|
| £4,000 | £2,000 | £1,200 | £800 |
| £5,000 | £2,500 | £1,500 | £1,000 |
| £6,500 | £3,250 | £1,950 | £1,300 |
| £8,000 | £4,000 | £2,400 | £1,600 |
| £10,000 | £5,000 | £3,000 | £2,000 |
Adapting in high-cost cities
In London and the South East, housing costs alone often exceed 30–40% of income for renters. If needs exceed 50%, reduce the wants category first before touching savings. A minimum 10% savings rate is a realistic floor for high-cost-of-living areas.
Emergency fundBuilding an emergency fund — how much and how fast
The 3–6 month rule
Financial advisers recommend keeping 3 to 6 months of essential living expenses in an accessible savings account. For a household with £4,000/month in essential expenses, the target emergency fund is £12,000–£24,000.
Who needs 6 months vs 3 months?
Six months of expenses is appropriate for: sole income households, commission or variable income earners, self-employed individuals, households with a single source of income, and anyone with health conditions that could affect employment. Three months is suitable for dual-income households with stable PAYE employment and good savings rate.
Where to keep it
Emergency funds should be in a high-interest savings account (not shares or property) — easily accessible without fees or tax complications. As of 2025, major bank savings accounts offer 4.5–5.5% interest, which is meaningful on a £15,000–£20,000 balance.
Invest surplusWhat to do with your monthly budget surplus
Priority order for surplus funds
Financial planners generally recommend this order: (1) Emergency fund — build to 3 months expenses first. (2) High-interest debt — credit cards at 20% should be cleared before investing. (3) pension contributions — salary sacrifice is highly tax-effective above £45,000 income. (4) Mortgage offset — guaranteed after-tax return equal to your mortgage rate. (5) Investment portfolio — shares, ETFs, or additional property.
The cost of not investing your surplus
A £1,000/month surplus invested in a diversified portfolio returning 7% annually becomes approximately £174,000 after 10 years and £520,000 after 20 years. The same money in a 5% savings account produces £155,000 after 10 years. Starting even one year earlier adds approximately £12,000 to the 10-year outcome.
FAQFrequently asked Frequently asked questions
Where these figures come from
Take-home figures on this page follow HMRC’s 2026/27 income tax and National Insurance rates, with budgeting guidance from the government-backed MoneyHelper service.
- Income Tax rates and Personal Allowance — GOV.UK — Income Tax rates.
- National Insurance rates — GOV.UK — National Insurance.
- Student loan repayment thresholds — GOV.UK — Repaying your student loan.
- Budgeting guidance — MoneyHelper.
Last checked: April 2026. Rates and thresholds are reviewed against the source of record each November, when annual adjustments for the following tax year are published.
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£70k income, £3,500 /month expenses £763 /month surplus
On a £70k salary (£4,263 /month net), with £3,500 /month in expenses, your budget surplus is approximately £763 /month (£9,156/year) — a savings rate of approximately 17.9%.
| Net income/month | £4,263 |
|---|---|
| Monthly expenses | £3,500 |
| Monthly surplus | £763 |
| Annual surplus | £9,156 |
| Savings rate | ~17.9% |
| 50/30/20 check | Needs: 47%, Wants: 35%, Save: 18% |
- Where to direct surplus? Emergency fund first
- Then: high-interest debt Credit cards, personal loans
- Then: offset or invest Offset mortgage or index funds
- Extra £200 /month to mortgage Save ~£85k interest on £500k loan
- Emergency fund target £10,500-£21,000 (3-6mo expenses)
£100k income, £4,000 /month expenses £1,713 /month surplus
On a £100k salary (£5,713 /month net), with £4,000 /month in expenses, surplus is approximately £1,713 /month (£20,556/year) — a 30% savings rate.
| Net income/month | £5,713 |
|---|---|
| Monthly expenses | £4,000 |
| Monthly surplus | £1,713 |
| Annual surplus | £20,556 |
| Savings rate | ~30% |
| 50/30/20: savings allocation | Exceeds 20% target |
- Investing £1,700 /month at 7% (20yr) £886,000
- Extra mortgage repayment £500 /month saves ~£145k on £500k
- Salary sacrifice £10k Save £4,000 tax — more surplus
- Pension salary sacrifice Reduces taxable income further
- Emergency fund check 4-6mo expenses = £16k-£24k
50/30/20 budget rule 20% savings target
The 50/30/20 rule divides after-tax income into: 50% needs (rent, groceries, bills, transport), 30% wants (dining, entertainment, holidays), 20% savings (emergency fund, debt payoff, investment).
| Needs (50%) | Housing, food, transport, bills |
|---|---|
| Wants (30%) | Dining, entertainment, subscriptions |
| Savings (20%) | Emergency fund, debt, investing |
| On £5,713 net/month | Needs £2,857 / Wants £1,714 / Save £1,143 |
| London/Manchester reality | Housing often forces 40-50% on needs |
| Minimum savings target | 10% if 20% not achievable |
- High housing cost city? Reduce wants to 20%
- With mortgage extra repayments? Count in savings bucket
- Student loan (Plan 2)? Treat as savings/debt bucket
- Annual expenses (insurance, car tax) Divide by 12 for monthly budget
- Review quarterly Adjust as income grows
Emergency fund — minimum and target sizes 3-6 months of essential expenses
Financial advisers recommend an emergency fund of 3-6 months of essential living expenses. Keep it in an easy-access savings account — accessible, not invested in shares or property.
| Minimum target | 3 months expenses |
|---|---|
| Recommended target | 6 months expenses |
| On £3,500 /month expenses | £10,500-£21,000 |
| Where to keep it | Easy-access savings account |
| Best UK savings rate (2026) | ~4.0-4.5% |
| Lock up in fixed-rate bond? | No — needs to be accessible |
- Single income household? Target 6 months — higher risk
- Dual income household? 3 months often sufficient
- Build it before investing Foundation before wealth building
- Offset mortgage works too Interest saved while accessible
- After emergency fund? Then high-interest debt, then invest
£50,000 income — monthly net £3,293 /month net
On a £50,000 salary, your monthly take-home is approximately £3,293/month after income tax and National Insurance. At £3,000 /month expenses this leaves a £293 /month surplus — an 8.9% savings rate.
| Gross salary | £50,000/year |
|---|---|
| Monthly net | £3,293/month |
| Example expenses | £3,000/month |
| Monthly surplus | £293/month |
| Annual surplus | £3,516 |
| Savings rate | ~8.9% |
- Reduce expenses to £2,800/month Surplus rises to £493/month
- Build emergency fund first £2,800-£5,000 (3 months)
- High-interest debt next Credit cards, personal loans
- Savings account (4%+) On £293 /month after 5yr = £19,400
- Increase income Part-time, skill development
£70,000 income — monthly net £4,263 /month net
On a £70,000 salary, your monthly take-home is approximately £4,263/month. At £3,500 /month expenses this leaves ~£763 /month surplus — a 17.9% savings rate, just short of the 20% target.
| Gross salary | £70,000/year |
|---|---|
| Monthly net | £4,263/month |
| Example expenses | £3,500/month |
| Monthly surplus | £763/month |
| Annual surplus | £9,156 |
| Savings rate | ~17.9% |
- Invest £1,000 /month at 7% (20yr) £520,000
- Emergency fund in 6mo £21,000 / £763 = ~28 months
- Extra £500 /month to mortgage Save ~£145k on £500k loan
- 50/30/20: at £4,263 Needs £2,132 / Wants £1,279 / Save £853
- Salary sacrifice £5k/year Save £2,000 tax, more surplus
£80,000 income — monthly net £4,746 /month net
On an £80,000 salary, take-home is approximately £4,746/month. The 50/30/20 rule suggests: needs £2,373, wants £1,424, savings £949/month.
| Gross salary | £80,000/year |
|---|---|
| Monthly net | £4,746/month |
| 50% needs budget | £2,373/month |
| 30% wants budget | £1,424/month |
| 20% savings target | £949/month |
| Annual savings at 20% | £11,388 |
- Mortgage at £80k? ~£360k borrowing capacity
- Emergency fund target £10,500-£21,000 (3-6mo x £3,500)
- Salary sacrifice benefit £5k saves £2,000 tax
- Student loan (Plan 2) at £80k ~£4,743/year (9% above £27,295)
- Employer pension ~£4,000/year (5%)
£100,000 income — monthly net £5,713 /month net
On a £100,000 salary, take-home is approximately £5,713/month. The 50/30/20 rule suggests saving £1,143/month. Investing that at 7% for 20 years builds approximately £595,000.
| Gross salary | £100,000/year |
|---|---|
| Monthly net | £5,713/month |
| 50% needs budget | £2,857/month |
| 30% wants budget | £1,714/month |
| 20% savings target | £1,143/month |
| Annual savings at 20% | £13,716 |
- £1,143 /month at 7% for 20yr £595,000
- Mortgage extra repayments £500 /month saves £145k on £500k loan
- Salary sacrifice £10k Reclaims personal allowance — big saving
- Student loan (Plan 2) at £100k ~£6,543/year
- Emergency fund target £12,500-£25,000 (3-6mo)
£120,000 income — monthly net £6,346 /month net
On a £120,000 salary, take-home is approximately £6,346/month. The 50/30/20 split allows for £1,269 /month in savings. At this income level, salary sacrifice into a pension is particularly tax-effective.
| Gross salary | £120,000/year |
|---|---|
| Monthly net | £6,346/month |
| 50% needs budget | £3,173/month |
| 30% wants budget | £1,904/month |
| 20% savings target | £1,269/month |
| Annual savings at 20% | £15,228 |
- Salary sacrifice £10k Save £4,000 tax/year
- Student loan (Plan 2) at £120k ~£8,343/year
- Employer pension on £120k ~£6,000/year
- £1,269 /month at 7% for 20yr £661,000
- 50/30/20 harder in London? Housing often >50% of budget
£150,000 income — monthly net £7,607 /month net
On a £150,000 salary, take-home is approximately £7,607/month. High earners at this level benefit significantly from salary sacrifice into a pension (40% higher-rate savings) and ISAs.
| Gross salary | £150,000/year |
|---|---|
| Monthly net | £7,607/month |
| 20% savings target | £1,521/month |
| Income above £50,270 | 40% higher rate |
| Personal allowance | Tapered away above £100k |
| Employer pension | ~£7,500/year (5%) |
- Salary sacrifice £15k/year Save £6,000 tax
- Salary sacrifice below £100k Restores personal allowance
- £1,521 /month at 7% for 20yr £792,000
- Student loan (Plan 2) at £150k ~£11,043/year
- Pension annual allowance £60,000 (2026/27)
50/30/20 rule at £70k net ~£4,263/month Needs £2,132 / Wants £1,279 / Save £853
Applying the 50/30/20 rule to a £70k salary (£4,263 /month net): spend 50% on needs (£2,132), 30% on wants (£1,279), and save 20% (£853 /month). The £853 savings rate builds £148,000 in 10 years at 7%.
| Monthly net | £4,263/month |
|---|---|
| 50% needs | £2,132/month |
| 30% wants | £1,279/month |
| 20% savings | £853/month |
| Annual savings | £10,236 |
| 10yr at 7% | £148,000 |
- High rent city? Needs may exceed 50%
- Student loan (Plan 2)? Part of needs or savings?
- Mortgage repayments? Count as needs
- Savings rate reality check 20% is the goal — start at 10%
- Emergency fund from savings First 3-6 months expenses
50/30/20 rule at £100k net ~£5,713/month Needs £2,857 / Wants £1,714 / Save £1,143
Applying the 50/30/20 rule at £100k (£5,713 /month net): needs £2,857, wants £1,714, savings £1,143/month. The £1,143 /month savings builds approximately £595,000 in 20 years at 7%.
| Monthly net | £5,713/month |
|---|---|
| 50% needs | £2,857/month |
| 30% wants | £1,714/month |
| 20% savings | £1,143/month |
| Annual savings | £13,716 |
| 20yr at 7% | £595,000 |
- Student loan eats into savings? ~£545/month (Plan 2)
- Offset mortgage for savings? Interest saved vs 4% savings
- Savings beyond 20% Accelerates wealth build greatly
- London: needs often 60%+ Adjust wants to 20%
- Pension on top? Employer contributions — not in this calc
50/30/20 rule at £120k net ~£6,346/month Needs £3,173 / Wants £1,904 / Save £1,269
At £120k (£6,346 /month net), the 50/30/20 rule allocates £1,269 /month to savings — building approximately £661,000 in 20 years at 7%. At this income level, salary sacrifice into a pension should be maximised first.
| Monthly net | £6,346/month |
|---|---|
| 50% needs | £3,173/month |
| 30% wants | £1,904/month |
| 20% savings | £1,269/month |
| Annual savings | £15,228 |
| 20yr at 7% | £661,000 |
- Salary sacrifice first (£10k) Saves £4,000 tax — effective 30% savings rate
- Mortgage offset allocation High rate return on savings bucket
- Student loan (Plan 2) at £120k ~£695/month — reduces wants budget
- Increase wants to 30%? Fine if needs are genuinely 50%
- Higher-rate band? 40% above £50,270
10% savings rate — minimum recommended £426 /month on £70k salary
A 10% savings rate is the commonly cited minimum financial health benchmark. On a £70,000 salary (£4,263 /month net), this is £426/month. At 7% over 20 years this builds approximately £222,000.
| Savings rate | 10% |
|---|---|
| On £70k salary | £426/month |
| On £100k salary | £571/month |
| 20yr at 7% on £426/month | £222,000 |
| Vs 20% savings rate | Half the wealth after 20yr |
| Starting point? | If 20% is too hard, start here |
- Build to 20% over time Add 1% per year as income grows
- Automate savings Pay yourself first approach
- 10% in offset or savings? Depends on whether you have a mortgage
- Emergency fund from 10% First 6 months
- Pension on top of 10% Employer contributions are separate
20% savings rate — 50/30/20 target £853 /month on £70k salary
The 50/30/20 rule targets 20% savings. On £70,000 salary this is £853/month. At 7% over 20 years, this builds approximately £444,000 — well on track for a comfortable retirement alongside your workplace pension.
| Savings rate | 20% |
|---|---|
| On £70k salary | £853/month |
| On £100k salary | £1,143/month |
| 20yr at 7% on £853/month | £444,000 |
| With pension on top | £700k+ at 67 |
| PLSA comfortable standard | £43,100/year (single) |
- Mortgage offset strategy? Saving goes to offset first
- Invest in ETFs? After emergency fund and debt cleared
- 50/30/20 is a guide Adjust for your circumstances
- High London rent issue May need to reduce wants to 20%
- Student loan (Plan 2) reduces effective rate Account for repayments
30% savings rate — excellent £1,279 /month on £70k salary
A 30% savings rate on a £70,000 salary means saving £1,279/month. Over 20 years at 7% this builds approximately £666,000. This rate combined with your workplace pension is sufficient for early or comfortable retirement.
| Savings rate | 30% |
|---|---|
| On £70k salary | £1,279/month |
| On £100k salary | £1,714/month |
| 20yr at 7% on £1,279/month | £666,000 |
| With workplace pension | Employer adds on top |
| PLSA comfortable standard | Achievable well before 67 |
- How to achieve 30% Minimise housing cost, no car loans
- Salary sacrifice into a pension Reduces tax, counts toward 30%
- FIRE potential? 30% rate opens early retirement path
- Partner income helps Household rate matters
- Lifestyle trade-offs Reduce wants to 20%
50% savings rate — FIRE path £2,132 /month on £70k salary
A 50% savings rate is the target for the FIRE (Financial Independence, Retire Early) movement. On £70,000 net income (£4,263 /month) this means saving £2,132/month. At 7%, financial independence in approximately 17 years.
| Savings rate | 50% |
|---|---|
| On £70k salary | £2,132/month |
| Years to FI at 50% rate | ~17 years |
| On £100k salary | £2,857/month |
| FI in ~14yr at £100k/50% | Using 4% withdrawal rule |
| Lifestyle required | Very lean living costs |
- FIRE: 4% rule target 25x annual expenses
- £30k/year spend, target £750k Achievable in ~15-17yr
- Pension access age 57 FIRE before then needs ISA/GIA assets
- Geographic arbitrage? Lower-cost location helps
- House hacking strategy Live in one unit, rent others
Worked examples
| Inputs | Monthly surplus | Note |
|---|---|---|
| 6,500 income, 5,200 expenses | £1,300 | 1,300 a month; 20% savings rate; emergency fund in 12 months |
| A 20,000 goal at 5% return | £1,300 | about 15 months |
| A deficit | -£500 | −500 a month |
FAQFrequently asked questions
What is a budget surplus?
A budget surplus is the amount remaining when your after-tax income exceeds your total monthly expenses. If you earn £6,000/month net and spend £4,200, your surplus is £1,800. This money is available for savings, investment, or debt repayment.
Should I include super in my income?
No — employer pension contributions go directly to your pension fund and are not available for day-to-day budgeting. Use your take-home pay (net after tax, National Insurance, and any Student Loan repayment). Super grows separately and is only accessible at retirement.
What expenses should I include?
Include all recurring monthly costs: rent/mortgage, groceries, utilities (electricity, gas, internet, phone), transport (car payments, fuel, public transport, registration, insurance), subscriptions, gym, dining out, entertainment, clothing, personal care, and any loan repayments. Do not include one-off annual costs — divide these by 12 to get a monthly equivalent.
What is a healthy surplus percentage?
The 50/30/20 rule suggests saving 20% of net income. In practice, 10–15% is the UK median. A surplus below 10% of net income leaves little buffer for unexpected expenses. Above 30% is excellent and allows rapid wealth accumulation.
How do I reduce expenses to create a surplus?
Start with the largest expense categories: housing (consider refinancing, downsizing, or a flatmate), transport (public transport vs car ownership analysis), and food (meal planning reduces grocery and dining bills significantly). Subscriptions and memberships are often the easiest quick wins — audit everything you pay monthly. Sources
The sources behind this calculator
- Corporate Finance Institute — EBITDA — why EBITDA is a non-GAAP measure with no single definition
- US SEC — Non-GAAP Financial Measures, Compliance & Disclosure Interpretations — the disclosure rules that exist precisely because EBITDA is not standardised
- Financial Reporting Council — the UK accounting and audit regulator
Last checked: September 2026. These are standard management-accounting definitions; where a term has no single agreed definition, the page says so.