How much cash does your checking account really need?
Most of what sits in checking is idle. Tell it what you have and what’s due, and it tells you each day how much to keep in checking and how much to park in savings — then brings money back just in time for each bill. It starts with an example; change any number below.
Illustrative, not advice. Everything here is fictional and runs entirely in your browser — nothing you enter is sent or saved, and the numbers only appear in the page address when you tap “Copy a link.” Rates are round numbers, not market quotes.
Today’s move
Do this today
…
Leave it all in checking
Follow this plan
You gain
What that adds up to
Day by day
Only days where something happens. The highlighted row is today.
Cash sitting in checking
The dashed line is leaving everything in checking. The solid line is the plan: only what the next few days of bills need.
Your numbers
1Your money
Add up everything in your low-interest checking accounts — business and personal together — and what’s in your high-yield savings.
All accounts combined.
APY — usually close to 0.
APY of your high-yield account.
2Bills paid from checking
Credit cards come out on their due date, every month. Everything else (rent, utilities, insurance…) is lumped into one monthly total.
An average is fine.
3Money you expect in
Invoices or paychecks you’re waiting on. They land in checking on the date you give.
4How your transfers work
Moving money between your banks takes time. Tell it how long each direction takes so the plan sends money early enough to arrive when it’s needed.
Up to this long before it earns savings interest.
Weekends and bank holidays don’t count.
Extra cash left in checking, just in case.
How it works: every business day the plan keeps in checking only what the bills due before money could come back from savings need (plus your cushion), sends the rest to savings, and brings money back from savings just in time — counting weekends and US bank holidays. It only advises; it never moves money. This demo came out of a real build — read the field note.