A monthly budget calculator answers one simple question: after my must-pay bills and savings, how much can I actually spend this month?
You enter your take-home pay (money after tax), your fixed bills (rent, insurance, loan minimums), and how much you want to save. The calculator shows what is left for variable spending — groceries, gas, dining out, subscriptions, and fun.
Take-home pay − Fixed bills − Savings = Left for variable spending
This is the same starting math used in our monthly budget guide. The calculator does not replace tracking — it gives you a number to split across categories in Ziko or on paper.
Real-life example (try this in the calculator)
Marcus earns $4,200 per month after tax. His fixed bills never change. He wants to save $500 before spending on anything flexible.
What Marcus pays
Amount
Calculator field
Take-home pay (2 paychecks)
$4,200
Monthly take-home pay
Rent
$1,400
Fixed monthly bills (add all)
Car insurance
$120
Phone + internet
$140
Student loan (minimum)
$190
Fixed total
$1,850
Emergency fund + extra debt
$500
Planned savings
$4,200 − $1,850 − $500 = $1,850 left for groceries, gas, dining out, and personal spending this month.
Marcus might split that $1,850 into caps — for example $450 groceries, $200 transport, $150 dining out, $100 subscriptions, $950 misc — and track each line in Ziko as he spends.
Tap Use example in the calculator to load Marcus's numbers, then change them to match your pay and bills.
How to read your results
Left for variable spending — Money for groceries, transport, dining, and fun. If this is negative, bills + savings exceed income; lower savings or cut fixed costs first.
Savings rate — Savings ÷ income. Many planners aim for 10–20% to start.
Fixed bills share — How much of your pay goes to non-negotiable bills. Over 50% often means housing or debt is tight.
50/30/20 wants target — A rough benchmark: 30% of income for wants. Compare your leftover number to this — you do not have to match it exactly.
Use net (take-home) pay only. Tax and payroll deductions are not available to spend.
Costs that stay about the same each month: rent, insurance, loan minimums, phone, internet, subscriptions at a set price. See our fixed vs variable guide.
Split it across spending categories (groceries, transport, fun) and track as you go. Ziko lets you set caps and log expenses without bank sync.
Turn this number into a real monthly plan.Set income, fixed bills, category caps, and email alerts in Ziko — free, no bank login.