We are the MonoTape team. A side hustle is only worth the effort if it actually makes money — and the only way to know is profit: revenue minus expenses. But expenses sneak in a few dollars at a time (materials, fees, shipping, that one tool you bought), and most people never sit down to add them up. By the time you wonder whether the side gig is paying off, the figures are scattered and gone. In this article we show how labeling revenue and expenses keeps your profit visible month after month.
Profit is simple math you never quite finish doing
Revenue minus expenses is not hard. The problem is that the expenses arrive piecemeal and a plain calculator forgets each one. You sold $600 of work, paid a $48 platform fee, $90 in materials, and $22 in shipping. Type 600 - 48 - 90 - 22 and you get $440 — but a week later, when another expense lands, you have to remember all four figures and start over.
A standard calculator never records that 90 was materials or 48 was the fee. So you lose the breakdown, which is the part that tells you where your margin is leaking. Without it, you are guessing whether the hustle is worth it rather than reading the answer off a record.
Revenue on top, expenses labeled, profit at the bottom
In MonoTape you give revenue its own line, list each expense by name, and define profit as revenue minus those expenses. The whole picture sits on the tape at once.
Now profit is not a number you computed once and lost — it is a line you can read any time. When a new expense comes up, you add one labeled line and the profit recalculates on its own. You can see exactly which costs are eating into the margin, so you know whether to raise prices or cut a cost.
Stack months to see the trend
One month tells you little; the trend tells you everything. Keep each month's profit as a labeled line and you can see whether the side hustle is growing or stalling. Fix a wrong figure in any month and the totals downstream update on their own — no need to recompute the whole history to correct one entry.
Knowing whether a side hustle pays is a tool problem, not an accounting skill. Put revenue and each expense on labeled lines, read profit off the tape, and stack months to see the trend. The math is easy; keeping it visible is what makes it useful.
MonoTape
A calculator notepad where you label your math and one edit recalculates everything. Profit tracking, estimates, split bills — whatever you calculate stays on the tape. Free to use.
Learn more about MonoTapeFrequently asked questions
How do I keep my expenses from getting lost?
Give each expense its own labeled line and subtract them from revenue to get profit. Every cost stays on the tape, so you can see exactly where your margin goes instead of recomputing from memory.
What happens when a new expense comes up later?
Add one labeled line for it and the profit line recalculates automatically. You never have to retype revenue and every other expense just to fold in one more cost.
Can I track profit across several months?
Yes. Keep each month's profit as a labeled line so you can see the trend and add a quarter total. Correct any month and the totals downstream update on their own.
Is it free?
Yes. Labeled calculations, references, auto-recalculation, and tape-style history — every feature mentioned here is free. It works on both iPhone and Android, and your data stays on your device.