- Enter monthly income in one currency.
- Enter living expenses separately from your investment contribution.
- Review the surplus and compare another contribution or expense amount.
Monthly budget calculator
Calculate monthly cash left after living expenses and an investment contribution. See how each amount changes the surplus. Free, without registration.
Left after expenses & investments
$0How to use this calculator
How the calculation works
Monthly surplus is income minus expenses and planned investment contributions. Taxes, exchange rates and investment returns are not added automatically.
What the monthly surplus means
It is income minus expenses and investment contributions. A contribution reduces available cash but remains a separate category: do not include the same contribution in expenses again. A negative result is a deficit under your inputs.
When payment dates matter
A positive monthly total does not guarantee cash on every day. This simple calculator has no payment dates or opening balance. The DCA budget dashboard adds an actual ledger, payment calendar, reserve, forecast and a trial comparison before applying changes.
The calculation is free and updates as you edit the fields. Investment returns, taxes and currency exchange are not added automatically.
Frequently asked questions
Are investment contributions included in expenses?
They are subtracted separately. Exclude the contribution entered in its own field from living expenses to avoid subtracting it twice.
Why can cash run out with a positive monthly surplus?
This tool compares monthly amounts only. Use the dashboard’s calendar forecast to check the timing of income and payments.
Does this select a safe investment amount automatically?
No. It gives an arithmetic surplus. Payment timing, debts, reserves, complete expenses and personal circumstances need separate consideration.
Is an account required?
No. This calculation is free. Use the dashboard for a transaction ledger and optional cross-device sync.