napkin math
Rough diner calculations
Napkin math is rough calculation done quickly and informally, as if scribbled on a napkin during a conversation.
The phrase emphasizes approximation over precision—good enough to test an idea or settle a dispute, not rigorous enough for final decisions: Some napkin math suggests we'd need about fifty thousand users to break even.
Also called back-of-the-envelope math.
- guesstimateRough, intuitive calculation
- back-of-the-envelopeRoughly calculated, informal
- solveFind the answer
- calculationMathematical problem-solving process
- roughUneven in surface
rough numbers · order of magnitude · rule of thumb · ballpark figure · mental models · heuristic · sanity check · reckoning · mental arithmetic · equation · scrappy · approximation · pen-and-paper · quick-and-dirty · spitballing · seat of pants · brainstorming · rounding
- estimatesestimate, estimation, ballpark, ballpark estimate, rough estimate
- math expressionsadd up, crunch numbers, number crunching, number cruncher, factor in
- workaroundsworkaround, workarounds, fixes, hacks, quick fix
napkin, napkins, math, maths, mathematics, mathematical, mathematically, mathematician, mathematicians