Free Recipe Converter & Scaler calculator
Resize any recipe in one step: enter a new serving count or a multiplier and every ingredient is scaled at once — flour, sugar, salt and leavening — updated live, as you type.
On this page13 sections
| Ingredient | As written | Scaled |
|---|---|---|
| Flour | 500 g | 750 g |
| Sugar | 200 g | 300 g |
| Butter | 115 g | 172.5 g |
| Milk / water | 240 ml | 360 ml |
| Salt | 2 tsp | 3 tsp |
| Baking powder / soda | 2 tsp | 3 tsp |
Below 2×, the straight linear amounts are reliable. Always judge bake time by doneness, not the clock.
Scaled amounts are linear. Salt, leavening and bake time need a cook's judgement.
Results are estimates. Consult a professional.
How the recipe scaler works
Scaling a recipe is one number applied to everything. That number is the scale factor — sometimes called the conversion factor or the recipe multiplier. The calculator finds it from the yield you have and the yield you want, then multiplies every ingredient by it at once. Double a batch and the factor is 2; halve it and the factor is 0.5.
Which way to enter it
Most cooks scale by servings: a cake for 4 that now needs to feed 6 gives a factor of 6 ÷ 4 = 1.5. Bakers often scale by multiplier instead, because dough is built in ratios rather than portions. The calculator takes either — pick the mode that matches how your recipe is written. For unit swaps along the way, the cooking converter handles volume-to-weight across ingredients.
How to find your recipe scaling factor
The factor does all the work, so it pays to get it right before you touch a single ingredient. It takes one division and a moment of thought about what you need to serve.
- Count the original yield. Read the recipe's "serves" or "makes" line. That is your denominator.
- Decide the new yield. How many servings, loaves or cookies do you need now? That is your numerator.
- Divide to get the factor. New yield ÷ original yield. For 6 servings from a recipe of 4, that is 1.5.
- Multiply every ingredient. Each amount times the factor. 500 g flour × 1.5 = 750 g; 2 tsp salt × 1.5 = 3 tsp.
A worked example: scaling a cake from 4 to 6 servings
Priya's loaf cake serves 4 and she needs it to serve 6 for a small gathering. The recipe lists 500 g flour, 200 g sugar and 2 tsp salt. She wants the new amounts without guessing.
Step 1 — Find the scale factor
Desired ÷ original: 6 ÷ 4 = 1.5×. Every ingredient gets multiplied by this one number.
Step 2 — Scale the bulk ingredients
Flour: 500 × 1.5 = 750 g. Sugar: 200 × 1.5 = 300 g. These scale cleanly because they carry the structure of the cake in direct proportion.
Step 3 — Scale the salt, then ease off
Salt scales to 2 × 1.5 = 3 tsp on paper. At only 1.5× that linear figure is fine. Past 2×, salt and leavening intensify at volume, so the guidance is to hold them near 75% of the calculated amount and taste before adding more.
Doubling and halving: a recipe scaling chart
If you just want the common factors at a glance, this table covers the everyday cases. The factor column is the number you multiply every ingredient by.
| What you want | Scale factor | 4 servings becomes | Note |
|---|---|---|---|
| Halve the recipe | 0.5 | 2 servings | Weigh ingredients — small amounts are hard to eyeball |
| Two-thirds batch | 0.67 | ≈ 3 servings | Awkward egg counts; measure partial eggs by weight |
| Keep as written | 1.0 | 4 servings | No change |
| One and a half | 1.5 | 6 servings | Linear amounts are reliable below 2× |
| Double the recipe | 2.0 | 8 servings | Hold salt and leavening near 75%; use ~1.5× the pan area |
| Triple the recipe | 3.0 | 12 servings | Consider splitting across two pans for even baking |
Factors assume a recipe written for 4 servings. Bulk ingredients scale linearly; salt, leavening and bake time do not — see the next section.
What does not scale linearly when you resize a recipe
Here is the catch every honest cook learns the hard way: the maths is linear, but the kitchen is not. A few things refuse to follow the scale factor, and treating them like flour is how a doubled batch comes out salty, sunken or burnt at the edges. This is where a calculator alone falls short and judgement takes over.
Salt and strong spices
Salt, chilli, garlic and other big flavours land harder at volume because the palate reads saltiness closer to logarithmically than in a straight line. A dish that needs 1 tsp of salt for 2 servings rarely wants 4 tsp at 8 servings — more like 2.5 to 3. At 2× or more, start at about 75% of the calculated amount and adjust to taste.
Leavening agents
Baking powder, baking soda and yeast drive a chemical reaction, not a flavour, and doubling them does not double the rise. Too much leavening makes a cake balloon and collapse in the centre or carry a metallic, soapy aftertaste. The professional guideline is to scale leavening to roughly 75% of the linear amount once the factor reaches 2× or higher.
Eggs that do not divide evenly
Scaling often lands on half an egg or one and a third. The reliable fix is weight: whisk a whole egg and measure out the part you need. King Arthur Baking notes a large egg weighs about 50 g, of which the yolk is around 14 g and the white about 35 g — so half an egg is roughly 25 g of whisked egg.
Pan size and bake time
Doubling the batter does not mean doubling the pan. A deeper bake traps heat and steam differently, so a doubled recipe wants about 1.5 times the surface area, not twice. Bake time shifts too: larger batches can run 10–20% longer and smaller ones 10–20% shorter, so set the timer as a hint and judge doneness by colour, smell and a probe.
The 75% leavening and salt guidance, the 50 g egg weight, and the pan-area and bake-time rules follow King Arthur Baking's guides to reducing a recipe and Serious Eats' coverage of scaling up.Why scaling by weight beats scaling by cups
Volume measures drift, and the drift gets worse the more you scale. A cup of flour can vary by 20% depending on how it is scooped, and that error multiplies with the factor — a small slip on a single batch becomes a real miss on a tripled one. Weighing removes the guesswork.
King Arthur Baking recommends a scale for exactly this reason, and it matters most when you reduce a recipe, where small absolute amounts leave little room for error. If your recipe is written in cups, convert it to grams first with the cups to grams converter, then scale the gram figures. Weight scaling also makes partial eggs and odd factors trivial, because grams divide cleanly where "one and a third eggs" does not.
Recipe scaling terms, defined
How accurate is this recipe scaler?
The arithmetic is exact. The scale factor is your desired yield divided by your original yield, and every scaled amount is that factor times the original — precise to the decimal, in whatever unit you entered. If your inputs are right, the bulk-ingredient figures are right.
The caveats are where craft enters. Salt, leavening and bake time do not follow the factor, so the calculator scales them linearly and then flags the 75% guidance and the doneness check rather than pretending the maths is the whole answer. Treat the scaled salt, spice and leavening as a starting point, weigh ingredients where you can, measure partial eggs by weight, and judge the bake by sight and a probe. Get those four habits right and a scaled recipe behaves like the original — just bigger or smaller.
Frequently asked questions about the free Recipe Converter & Scaler calculator
About this Recipe Converter & Scaler calculator
This recipe converter runs entirely in your browser. Nothing you type is sent anywhere — the scale factor and every scaled ingredient amount are computed live on your device as you change the servings or the multiplier.
It is one of our free cooking calculators, part of a wider library of free calculators covering the kitchen, the workshop and beyond.