We are the MonoTape team. Before a DIY project, you sit down to figure out roughly what the materials will cost — lumber, screws, paint, a couple of brushes, sandpaper — and halfway through the list you realize a plain calculator has already lost the plot. You have a number on the screen, but you cannot tell which items it covers, and when you want to swap in a cheaper board, you are typing the whole thing over again. The trouble is not that the math is hard. It is that a calculator throws away everything except the final number.
Why a DIY estimate turns into a retyping mess
A material estimate is rarely a single sum. Each item is really price times quantity: 8 boards at $6.50, three quarts of paint at $14.99, a box of screws, a pack of sandpaper. On a standard calculator you punch in 6.50 * 8 + 14.99 * 3 + ... and out comes a total. But the moment you decide to buy ten boards instead of eight, or the store is out of that paint, you start the whole chain again from the first keystroke.
A notes app has the opposite weakness. It will happily hold the list of items, but it will not do the arithmetic, so you end up bouncing between two apps and copying numbers by hand. What a DIY estimate actually needs is something that remembers each line as a named calculation and recomputes the total when one figure changes.
Add each material as a labeled line
That mid-project moment was exactly the case we built MonoTape for. As fast as a calculator, but like a notepad it keeps a record of what you calculated. For a material estimate, you give each item a label and enter it as price times quantity.
Your tape ends up reading like the shopping list itself, with the math built in.
Now the estimate is not just a number — it is a breakdown you can read. You can see at a glance that lumber is the biggest line, and that the screws barely move the total. When you stand in the aisle and the price tag does not match what you guessed, you fix that one line and the materials total updates on its own.
Change one number, get the new total instantly
The real payoff comes when the plan changes, which on a DIY project it always does. Decide to go with ten boards instead of eight? Rewrite the quantity on the Boards line and the total recalculates — no retyping the rest. Found cheaper paint, or want to see what the project costs if you skip the new brushes? Edit or delete that one line and watch the bottom line move. You can try three or four versions of the same estimate in under a minute.
A DIY estimate is a tool problem, not a math problem. Label every material as price times quantity, keep the breakdown on the tape, and edit only the line that changed. Everything is saved locally on your device, so your estimate is still there when you get back from the hardware store. For the closely related task of working out how much wallpaper or flooring you need, see our guide on calculating wallpaper and flooring quantity and cost, and if you want the general technique for never starting over, read how to stop retyping everything to fix one digit.
MonoTape
A calculator notepad where you label your math and one edit recalculates everything. Material estimates, work quotes, event budgets — whatever you calculate stays on the tape. Free to use.
Learn more about MonoTapeFrequently asked questions
Can I enter price times quantity on one line?
Yes. You can write a full expression like 6.50 times 8 on a single labeled line, so each material keeps both its unit price and its quantity right where you can see them.
What if I change a quantity later?
Edit just that one line and the materials total recalculates automatically. You never retype the rest of the estimate, so trying a bigger or smaller order takes a few seconds.
Will my estimate still be there after I close the app?
Yes. Everything is saved locally on your device, so your tape is waiting for you when you get home from the store. Nothing is uploaded anywhere.
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.