A budget that survives a real month
Split spending into fixed and variable costs, leave a buffer for unexpected costs, then track a month's spending and compare it with the plan. The difference between planned and actual amounts helps you learn from the month.
What a learner can do afterwards
- Build a one-month budget that separates fixed commitments from variable spending and carries a buffer line
- Track actual spending for a month, compare it with the plan and explain possible causes of differences
- Use recorded differences and expected changes to revise next month's budget within available income
1 · Read
You have planned saving toward a goal. A monthly budget also covers spending. Start with income you expect to have after deductions, such as tax. Fixed costs stay at the same amount over the planning period, though they can change later. Variable costs change with use, prices or choices. Food can be a variable cost and still be a need.
Leah has £180 available this month. She plans a fixed £20 phone payment, £40 for travel, £35 for food, £30 for fun, £35 for saving and a £20 buffer. These total £180. A buffer is money reserved for unexpected costs, not extra income. A surprise can exceed it. Spending, savings and buffer must fit available income; if their total is too high, revise the allocations.
Record each payment with its amount, date and category. Compare actual totals with the original plan. Actual minus planned is positive for spending above plan and negative for spending below it. For the size of the cash gap, subtract the smaller amount from the larger. Check the records for causes, such as a changed price or an unusual payment.
Percent means out of 100. Divide the gap by the positive planned amount to get a decimal, then multiply by 100. A £40 plan and £50 actual spending give a £10 gap: 10 ÷ 40 = 0.25 = 25 ÷ 100, so spending is 25% above plan. A decimal percentage such as 2.5% means 2.5 out of 100. For spending below plan, use the gap's size and say it is below. Name the planned amount as the reference. If the plan is £0, report the cash gap without dividing by zero.
A percentage compares a gap with its planned amount. It does not decide what to pay or change first. Check the cash amount, payment dates, needs and cause of the gap too. A small percentage on a large bill can still involve needed money. A large percentage on optional spending does not make that spending urgent.
Use records to revise next month's plan. A one-off taxi fare after a cancelled bus need not become a regular travel cost. Repeated higher food costs may need a new estimate. Check expected income and commitments too. If a required allocation rises while income stays the same, look for affordable reductions elsewhere. Add the revised spending, savings and buffer to check that the whole plan still fits.
Plan costs, savings and a limited buffer. Record actual spending, explain differences and revise within available income.
This monthly-budget lesson, its questions and flashcards were written for this dataset.
The readings and flashcards were written for this dataset. The linked video, Paying yourself first, is credited to Khan Academy. Its reuse terms have not been verified.
More to read
Do not allocate the same money twice
A practice budget has £240 available after deductions. Required spending takes £140, optional spending £45, saving £35 and a buffer £20. The allocations total £240.
The buffer is part of the £240 available. Calling it spare money and spending it again would count the same pounds twice. Savings are also an allocation, even though the money has not been used to buy anything yet.
List each allocation once and add the amounts. If the total exceeds available income, the plan needs changing. If essential costs cannot be covered, ask a trusted adult for help with the shortfall.
Make planned and actual records comparable
Keep the original plan beside the actual record. Use the same category names in both. Record each payment once, with its date and amount.
Suppose a bus fare appears under travel in the plan but under fun in the spending record. The category comparison will be misleading even if both totals were added correctly.
A notebook can hold these records. A spreadsheet can calculate totals from entered amounts. Check its cell references and included rows. A formula cannot include a payment that you forgot to record.
Connect this month's saving to a later goal
Suppose a £90 goal is three months away and you have nothing saved for it. Three monthly contributions of £30 would reach £90, if each month's budget can afford that contribution.
Write the £30 contribution in this month's plan alongside costs and a buffer. When you transfer it to savings, record the transfer so the money is not also treated as available spending money.
If this month's contribution changes, check what remains to be saved and how many contribution dates remain. The new calculation still needs an affordability check.
Find the reason behind a spending change
A travel total can rise because each fare costs more, because you make more journeys or because one unusual journey costs extra. The total alone does not distinguish those causes.
Look at the individual records. A regular fare increase may belong in next month's estimate. One special journey may not recur. Check what you expect to happen before choosing a new amount.
Keep the original plan visible. This lets you explain the difference rather than erase it. After revising categories, add all allocations again and compare the total with expected income.
Name the reference in a percentage comparison
A £30 plan followed by £36 spending has a £6 gap. Relative to the £30 plan, the increase is 6 ÷ 30 × 100 = 20%. Dividing by the actual £36 would answer a different comparison.
For a budget review, say that the percentage uses planned spending as its reference. This describes a difference from a plan, not the accuracy of a scientific measurement.
Keep the cash gap and its direction visible too. A percentage does not show whether a payment is urgent or necessary. If planned spending was zero, report the cash gap without calculating a percentage of that zero plan.
Explore more
2 · Watch
En anglaisTake it off screen
Where it sits
Learn first
Optional connections
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.