ExactUnits
↑↓ move ↵ open Esc close All shortcuts

Recipe scaling calculator

Scaling by servings is a straight ratio for ingredients. Tin area, cooking time and seasoning do not scale the same way, and the calculator says so.

cm
Scaled quantity
375.00
≈ Rounded Recipe scaling
Scaling factor
1.5000
As a percentage of the original
150.0 %
Tin diameter for the same depth
24.49 cm
Rough cooking-time multiplier A weak power law, not a rule. Always check for doneness.
1.129
Show the working
  1. Original servings = 4
  2. Servings you want = 6
  3. Quantity of one ingredient = 250
  4. Original tin diameter = 20
  5. Scaling factor = 6 / 4 = 1.5
  6. Scaled quantity = 250 * 1.5 = 375
  7. As a percentage of the original = 1.5 * 100 = 150
  8. Tin diameter for the same depth = 20 * sqrt(1.5) = 24.4949
  9. area_ratio = 1.5 = 1.5
  10. Rough cooking-time multiplier = 1.5^0.3 = 1.129 35

Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.

Scenarios & local history

Compare a saved scenario

Recent calculations

    The formula

    • scaled quantity = original x target servings / original servings
    • to keep the same batter depth, tin diameter scales with the square root of the factor

    Salt, spices, leavening and alcohol rarely scale linearly. Scale them at about three quarters of the factor and adjust to taste.

    Doubling a cake does not double its baking time. A bigger, deeper tin needs a lower temperature and a longer bake.

    Related calculators

    Settings

    Theme

    System follows your operating system and changes with it.

    Text size
    High contrast

    Maximises text and border contrast and removes the grid background.

    Graph-paper background
    Round to
    Notation
    Thousands separators
    Decimal mark
    Nearest fraction

    Shows the result as the nearest tape-measure fraction, with the error it costs.

    Accessibility & interaction
    Reduce motion Stops interface animations even when the operating system does not.
    Underline links Keeps links visually distinct without relying on colour.
    Larger touch targets Makes buttons and form controls easier to tap.
    Shorter reading lines Limits article width for easier scanning.
    Monochrome display Removes colour as an information cue.
    Always-visible focus Makes the keyboard focus ring persistent and stronger.
    Verbose screen-reader results Announces the complete conversion equation.
    Sticky action bars Keeps converter and calculator actions within reach.
    Select values on focus Replaces a value immediately when you start typing.
    Left-handed mobile layout Moves key mobile actions toward the left thumb.
    Your data

    Settings, recent conversions and favourites live in this browser only. Nothing is sent anywhere.

    Offline library