Children register tension long before they understand its cause. In the absence of an explanation they construct one, and the version they build is usually worse than what is actually happening — that someone is ill, that their parents are separating, that it is somehow their fault.
You do not owe them the details. You do owe them enough that it is not a secret with a shape they can see.
Say enough that it is not a mystery
Age-appropriate and honest beats comprehensive. For a younger child: “We owe some money and we are getting help sorting it out. It is a grown-up problem and we are handling it. You are not going anywhere and neither are we.”
Teenagers usually know more than you think and are often quietly angry about being managed. They tend to respond better to something closer to the truth, including that it is hard.
Name what is not changing
This is the part that does the work. School, home, the people who live in the house, the dog. Say them out loud specifically. Children calibrate on concrete details, not reassurance in general.
If something is changing — a move, a different school — say that plainly too, with as much notice as you can. Being told beforehand is survivable. Discovering it is not.
Let them ask twice
Children frequently come back a day or two later with the question they actually had. Leave the door open rather than treating it as one conversation that has been had.
Do not make them the confidant
It is a genuine temptation, particularly with an older child who is being kind about it, and especially if you are going through this alone. But it puts them in a role they cannot carry and often produces a fourteen-year-old who feels responsible for household finances. Take that weight to another adult — a friend, a counsellor, a support group.
What they will remember
Not the amount. Whether the adults were honest with them, and whether the house felt safe. Both of those are within your control even in the worst month of this.