We are the MonoTape team. A recipe says "serves 2," but guests are coming and you want to make enough for 5. The job is simple — multiply every ingredient by 2.5 — yet somehow you slip up every time. We know the feeling. Scaling portions is error-prone not because the math is hard, but because you repeat the same calculation once per ingredient, and each answer vanishes as you go. In this article we show how to scale a recipe without mistakes.
The real reason scaling goes wrong
To go to 5 servings, the factor is 5 / 2 = 2.5. Then you multiply the flour, sugar, eggs, milk, and so on, one at a time. On a standard calculator that means computing the flour, writing it on paper, computing the sugar, writing it down, and repeating. Every time the previous answer disappears, you stall: "wait, how many grams of sugar was that again?" With ten ingredients you do this ten times, and somewhere in there a forgotten multiply or a miscopied number is almost guaranteed.
What makes it worse is wanting to change the factor afterward. The moment you decide "actually, 4 servings is plenty," you are recomputing every ingredient from the top. That is why scaling a recipe is quietly stressful.
Put the factor on one line, multiply each ingredient by it
In MonoTape, you first give the scale factor itself a name on one line. Then each ingredient references that factor in its own calculation.
Each ingredient name becomes its line's label, so the new amounts all stay listed. Glance back while you cook and you see at once that sugar is 200 g. The previous answer never disappears, so you never stall.
Change the head count? Edit only the factor line
The strength of this setup shows when the head count changes. Going from 5 servings down to 4? Just edit the factor line to "4 / 2 = 2," and the flour, sugar, milk, and eggs all recalculate themselves. No recomputing each ingredient. Want half a batch? Set the factor to 0.5.
Scaling a recipe means repeating the same multiplication over and over. So decide the factor once and let each ingredient reference it, and both the mistakes and the busywork drop sharply. The more the head count is likely to change, the more auto-recalculation pays off.
MonoTape
A calculator notepad where you label your math and one edit recalculates everything. Recipe scaling, estimates, split bills — whatever you calculate stays on the tape. Free to use.
Learn more about MonoTapeFrequently asked questions
How do I figure out the factor?
Servings you want divided by the recipe's servings. To take a 2-serving recipe to 5, that's 5 / 2 = 2.5. In MonoTape you keep that factor on one line and have each ingredient reference it.
Can it handle tablespoons or "a pinch"?
Any amount you can express as a number (grams, ml, tablespoons) can be scaled by multiplying. For amounts that aren't numbers, like "a pinch" or "to taste," adjust by feel as you cook.
Do I recompute everything if the head count changes?
No. Edit the factor line and every ingredient referencing it recalculates automatically. Switch to 4 servings or half a batch with a single edit.
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.