50/30/20 budget calculator
The 50/30/20 rule is a simple, beginner-friendly framework for managing money, popularised by Elizabeth Warren in her book All Your Worth. It splits your monthly take-home pay into three buckets so you cover essentials, still enjoy life, and steadily build savings — without tracking dozens of line items. Enter your net income and this calculator shows each amount instantly.
How it works
The calculator takes your monthly take-home (net) income and divides it into three fixed proportions:
- 50% Needs — rent or mortgage, bills, groceries, transport, insurance
- 30% Wants — dining out, hobbies, subscriptions, entertainment
- 20% Savings & debt — emergency fund, investments, extra repayments
Each amount is simply your income multiplied by 0.50, 0.30 and 0.20. Use net rather than gross pay, because that is the money you actually control once tax and deductions are taken out.
Example
On a monthly take-home income of £2,500:
| Category | Share | Amount |
|---|---|---|
| Needs | 50% | £1,250.00 |
| Wants | 30% | £750.00 |
| Savings & debt | 20% | £500.00 |
So you would aim to keep essentials under £1,250, spend up to £750 on discretionary wants, and direct £500 toward savings and paying down debt.
Treat the numbers as a starting point and shift money between categories to fit your circumstances. Every calculation runs locally in your browser — nothing is uploaded.
When the split does not fit
The 50/30/20 rule is a framework, not a law. Real life often pushes outside the neat thirds:
- High-cost city: Rent alone can swallow 40-50% of take-home pay before groceries, utilities, or transport. In that case, compress the wants bucket first and accept a temporarily smaller savings percentage while you work on reducing fixed costs.
- Debt-heavy starting point: Some financial planners suggest temporarily redirecting the wants 30% toward aggressive debt pay-down, running closer to a 50/50 split of needs versus debt-and-savings until high-interest balances are cleared.
- Variable income: Freelancers and self-employed people often apply the percentages to a three-month rolling average of income rather than this month’s figure, to smooth the wild swings.
Deciding what goes in each bucket
The dividing line between needs and wants is often blurred. A useful test: if you stopped paying for it tomorrow and nothing serious happened within a month, it is probably a want. A few contested examples:
| Item | Typical category | Reasoning |
|---|---|---|
| Basic phone plan | Need | Required for work and emergencies |
| Streaming services | Want | Pausable without serious consequence |
| Gym membership | Depends | Need if health-critical; want if optional |
| Work lunch delivery | Want | Groceries and packed lunch cover the need |
| Pet insurance | Need or want | Depending on your pet’s medical situation |
Using the 20% bucket effectively
The savings-and-debt portion works best as a waterfall:
- Build a one-month emergency buffer first (even a small cushion stops debt from growing)
- Capture any employer pension match (it is an instant 50-100% return)
- Pay off high-interest debt (credit cards, buy-now-pay-later) before investing
- Invest the remainder in a pension, ISA, or other long-term vehicle
Even if the 20% is temporarily impossible, the framework tells you exactly which number to improve: either increase income, lower needs (renegotiate rent, switch energy tariffs), or trim wants until the savings line is positive.