Budget calculator
List your monthly income and spending to see what’s left and how it compares with the 50/30/20 rule.
About the budget calculator
List your monthly income and spending to see what’s left and how it compares with the 50/30/20 rule.
Part of SmartCalcy’s finance tools. It runs in your browser with no account, uses your own currency and units (change them at the top of the page), and gives estimates for information only, so check official guidance before you rely on a result.
How to use the budget calculator
What it calculates and when to use it
Lists your monthly income and spending, shows what is left and compares your needs, wants and saving with the 50/30/20 rule.
How to use it, step by step
- Add your sources of monthly income after tax.
- List your spending and mark each item as a need, a want or saving or debt repayment.
- Read the amount left and the comparison.
What each input means
- Type – Need: essentials. Want: choices. Saving or debt: savings and extra debt payments.
How to read the results
- Left over or overspent – Income minus spending.
- 50/30/20 table – Your shares of income against the 50, 30 and 20 targets.
The formula
Left = total income − total spending. Share = group total ÷ total income. The 50/30/20 rule suggests 50% needs, 30% wants and 20% saving.
A worked example
Income of 2,800 against needs of 1,700, wants of 350 and saving of 300 leaves 450 a month, 5,400 a year. Needs are 61% of income, above the 50% guide.
Assumptions and limits
- Monthly amounts. Convert irregular bills to a monthly average.
- The 50/30/20 split is a guide, not a rule.
Common mistakes
- Leaving out irregular costs such as car repairs and gifts.
Frequently asked questions
What if my needs exceed 50%?
In high-cost areas that is common. Focus on keeping saving steady and reducing wants.
Related tools
Details
- Per year
- £5,400if nothing changes
- Savings rate
- 27%saved plus unspent
Against the 50/30/20 rule
| Group | Amount | Share | Target |
|---|---|---|---|
| Needs | £1,700 | 61% | 50% |
| Wants | £350 | 13% | 30% |
| Saving and debt | £300 | 11% | 20% |