Both ratios ask the same question: can the business cover what is due soon out of what it can turn into cash soon.
Quick ratio counts cash and money owed to you against what you owe.
Current ratio counts the same, plus stock.
Above 1.0 means yes, on paper.
Why two
Because stock is only worth what somebody pays for it, and only when they do.
A business with a healthy current ratio and a weak quick ratio is solvent in inventory and short of cash — it can pay its bills if it sells what is on the shelf, at the price it expects, in time. That is three assumptions in a sentence about paying next month's rent.
The quick ratio is the harder question, and it is the one a lender asks.
What the numbers mean in practice
Below 1.0 — more falling due than you can readily cover. Not automatically a crisis, because timing matters more than the ratio does, but it is the state where one late-paying customer becomes a problem.
Around 1.5 to 2 — comfortable for most service businesses.
Well above 2 — safe, and possibly cash sitting idle that could be working. Worth asking rather than assuming; a deliberate reserve is a decision and this ratio cannot tell the difference between a reserve and a habit.
The limit worth knowing
A ratio is a snapshot and takes no view on when. Receivables due in ninety days and bills due on Friday count the same in it, and they are not the same at all.
Read it alongside cash runway, which is about time, and days to get paid, which is about whether the receivables in the numerator actually arrive when you think.