We are the MonoTape team. Filing an expense report is one thing; explaining it three weeks later when someone in finance asks “what is this $86.40?” is another. By then the calculation is long gone — you added a few amounts on a calculator, typed the total into a form, and the steps evaporated. The trouble is not that you did the math wrong. It is that the math left no record of what it was. In this article we show how to keep an expense calculation you can explain at any time.
A calculator total can’t answer “what was this for?”
A reimbursement number is rarely a single purchase. It is a taxi plus a client lunch plus a parking fee, summed into one figure. Punch 24.00 + 48.60 + 13.80 into a calculator and you get 86.40 — but the calculator throws away the three parts the instant you press the next key. Weeks later you are staring at 86.40 with no idea how it broke down, and no way to defend it.
A spreadsheet would solve it, but opening one on your phone for a three-line expense is overkill, and a notes app records the words without doing the sum. What you want is something that adds the numbers and keeps each one named, so the breakdown survives alongside the total.
Label each cost and the breakdown stays attached
In MonoTape you give each expense a label — the purpose and the date — and add it to the tape. The total is computed for you, and because the lines are named, the report explains itself.
When finance asks about the $86.40, you open the tape and read it straight off: taxi, lunch, parking, with dates. You answer by reading, not by remembering. And because the lines stay on the tape, the next report does not start from a blank slate either.
Correct one line and the total fixes itself
Expense numbers change. The lunch turns out to be $52.10, or one item gets rejected and has to come off. With a standard calculator that is a full retype. In MonoTape you edit just that line and the reimbursement total recalculates on its own. Remove the parking, fix the taxi fare — the total stays correct without you touching anything else.
To be clear, MonoTape is a calculator memo, not an expense-management system. It does not submit reports, attach receipts, or sync to your company’s tools. What it gives you is a labeled, editable record of how each total was built — the part a plain calculator throws away and the part finance always wants back.
An explainable expense report is a record problem, not a math problem. Label each cost, let the tape hold the total and the breakdown, and edit only the line that changed. The number stays defensible long after you filed it.
MonoTape
A calculator notepad where you label your math and one edit recalculates everything. Expense totals, estimates, split bills — whatever you calculate stays on the tape. Free to use.
Learn more about MonoTapeFrequently asked questions
Does MonoTape submit expense reports?
No. It is a calculator memo, not an expense-management system. It does not file reports or attach receipts. It keeps a labeled, editable record of how each total was built, which you can read out whenever you are asked.
How do I explain a total weeks later?
Open the tape and read the labeled lines. Each cost is named with its purpose and date, so the breakdown is right there next to the total.
What if one amount changes or is rejected?
Edit or delete that single line and the total recalculates automatically. You never retype the whole calculation.
Is it free, and is my data private?
Yes, it is free, and everything is saved locally on your device, never uploaded. It works on both iPhone and Android.