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Portions and preparation · USDA nutrition

Onions calories per cup: 32–157 across 6 of 7 named USDA examples

Across 6 of 7 named USDA examples, a cup contains 32–157 calories. Their listed weights span 100–225 g, so each calorie value is calculated from that example's own gram weight and published calories per 100 g. The remaining 1 specifically named example does not list that exact household measure.

Portion calculator

Estimate your portion

Choose a source measure or enter the weight you ate.

Preparation and portion

Named measures come from this exact source record.

Estimated for 108 g

79calories

Onions, cooked, fat added

Protein
1.4 g
Carbs
11.4 g
Fat
3.4 g

These values scale the selected reference food by weight. Ingredients, preparation, and portion size can change your meal’s estimate.

FoodData Central Survey Foods (FNDDS) · FDC 2709951 Full nutrition profile →

Compare all 7 food records, nutrition tables and USDA sources

The 7 exact records in this guide report 5–79 calories in the records' own listed source servings and 32–73 calories per 100 grams. Those are observations from named database records—not a universal range or an estimate of an unseen plate.

Match my meal

Start with the description closest to what you ate

For Onions, begin by separating “Onions, cooked, fat added” from “Onions, raw.” Choosing a card filters this source set; it does not infer the portion or fill in ingredients the chosen description does not name.

Showing the first 6 of 7 linked records.

Equal-weight view

How onions records compare at 100 grams

Five rank landmarks are shown from all 7 cited records: minimum, 25th-ranked, median-ranked, 75th-ranked, and maximum. Weight is held at 100 grams; source-serving weights are listed in the table.

  1. Minimum: Onions, green, raw 32 kcal
    32 kcal
  2. 25th-ranked landmark: Onions, for use on a sandwich 38 kcal
    38 kcal
  3. Median-ranked landmark: Onions, cooked, no added fat 47 kcal
    47 kcal
  4. 75th-ranked landmark: Onions, pearl, cooked 50 kcal
    50 kcal
  5. Maximum: Onions, cooked, fat added 73 kcal
    73 kcal

Shared basis: 100 g · kilocalories

What this page compares

Named source records, not one universal meal

This guide keeps 7 named USDA records in view: 7 direct matches. They span 2 source categories, including Onions and Vegetables on a sandwich. The exact descriptions remain the unit of comparison; the familiar heading is only the doorway into the evidence.

Why these records appear together: The deterministic grouping rule “normalized first description segment” placed these 7 records together under the exact grouping key “onions.” That rule determines membership before any nutrition result is read.

For Onions, this page can compare 7 named records from FDC 2709951 through FDC 2709795. It cannot observe which preparation was eaten, recover unnamed additions, or supply the eaten grams.

Read the shared calculation, provenance, and uncertainty method →

Editor’s decision brief

The three facts to carry into the table

Carry the denominator, exact identity, and strongest observed contrast into every number below.

Portion

15–108 g before composition

The largest source amount is 7.2× the smallest. Read per-serving calorie differences with that mass gap in view.

Composition

41 kcal separates the fixed-weight endpoints

The lower endpoint is “green, raw”; the higher is “fat added.” This isolates density, not ingredient causation.

Discriminator

1.6 g fiber gap per 100 g

Of protein, fiber, and sodium, the strongest normalized contrast is between “pearl” (1.4 g) and “green, cooked” (3.0 g).

Observed source examples

Three landmarks inside this source set—not universal endpoints

The cards are ordered by calories in each record's listed serving. Serving weights differ, so use per-100-gram values to compare composition. These selected records do not define a calorie range for every onions.

Important: “Lower” begins with Onions, green, raw; “higher” ends with Onions, cooked, fat added, using each record’s own source amount. Those labels order this selected set only—they are not endpoints for every onions meal.

Full comparison

Compare every selected FNDDS record

For Onions, serving columns preserve each record’s own listed amount, while calories per 100 g hold weight constant. A dash means the cited record does not supply that field; it does not mean the nutrient is absent.

On smaller screens, focus the table and scroll horizontally to read every column.

USDA records selected for the Onions nutrition guide
Exact source record Match Source amount Calories kcal / 100 g Protein Fiber Sodium USDA
Onions, cooked, fat added Direct name match 108 gUSDA reference amount 79 kcal 73 1.4 g 2.1 g 159 mg FDC 2709951 ↗
Onions, cooked, no added fat Direct name match 105 gUSDA reference amount 49 kcal 47 1.4 g 2.1 g 148 mg FDC 2709950 ↗
Onions, for use on a sandwich Direct name match 15 gUSDA reference amount 6 kcal 38 0.1 g 0.3 g 0 mg FDC 2710252 ↗
Onions, green, cooked Direct name match 15 gUSDA reference amount 9 kcal 63 0.3 g 0.5 g 24 mg FDC 2709953 ↗
Onions, green, raw Direct name match 15 gUSDA reference amount 5 kcal 32 0.3 g 0.4 g 2 mg FDC 2709794 ↗
Onions, pearl, cooked Direct name match 93 gUSDA reference amount 47 kcal 50 0.7 g 1.3 g 120 mg FDC 2709952 ↗
Onions, raw Direct name match 15 gUSDA reference amount 6 kcal 38 0.1 g 0.3 g 0 mg FDC 2709795 ↗

Portion analysis

Serving total and calorie density answer different questions

The listed source amounts run from 15 to 108 grams—a 93-gram gap before composition enters the comparison. Their own source servings run from 5 calories for “green, raw” to 79 for “fat added.” At a fixed 100 grams, “green, raw” is 32 calories and “fat added” is 73—a fixed-weight separation of 41 calories. For Onions, the serving view answers “how much is in the database portion?”; the 100-gram view answers “how concentrated is the matched record?” Neither reveals how many grams were actually eaten.

The scaling rule: multiply a per-100-gram value by eaten grams ÷ 100. The arithmetic is exact; the result is only as defensible as the record match and portion estimate.

Preparation analysis

The long description carries the evidence

The published descriptions distinguish forms such as “cooked, fat added”, “for use on a sandwich”, “green, cooked”, “pearl, cooked”, and “raw”. The source formulations contain 9 distinct ingredient codes; examples that appear in only part of the set include salt, table, oil or table fat, nfs, onions, raw, and onions, spring or scallions (includes tops and bulb), raw. On this Onions page, those rows make the records inspectable, but they are not a controlled experiment: they cannot tell us that one named input, by itself, caused a nutrient difference.

Database precision is not meal certainty. Retain the exact description beside the number so later corrections remain possible.

What changes the comparison

Four drivers worth checking before choosing a record

The family label “Onions” cannot resolve the differences between Onions, cooked, fat added and Onions, raw. The four checks below identify the record wording, source weight, and formulation evidence that can.

  1. 01

    Source weight before serving calories

    The source amounts span 15–108 grams. Compare per 100 grams before reading a serving-calorie gap as a composition gap.

  2. 02

    The words that split the family

    Representative record-level distinctions include “cooked, fat added”, “for use on a sandwich”, “green, cooked”, “pearl, cooked”, and “raw”. Those phrases are evidence for choosing a record, not decorative subtitle text.

  3. 03

    Formulation evidence, with limits

    9 source-input codes appear across the selected records. Their presence and listed weights describe USDA formulations, not finished plated proportions.

  4. 04

    The unresolved plate

    Even “Onions, cooked, fat added” leaves the eaten grams and unnamed oils, sauces, toppings, substitutions, or leftovers unresolved. Preserve those Onions unknowns for correction instead of converting them into false precision.

Record matching

Match identity first; scale quantity second

Read the source name as a sequence of decisions. First confirm that onions is the right meal family. Then resolve the phrases that actually separate this set—“cooked, fat added”, “for use on a sandwich”, “green, raw”, and “raw”—before comparing gram weight. If a package, menu, or known recipe provides a closer first-party description, prefer it and keep this USDA record as a transparent fallback.

A practical matching checklist

  1. Read the complete Onions source description, including preparation and additions.
  2. Compare the listed source weight with the amount actually eaten.
  3. Prefer a current package or restaurant source when a specific branded item is known.
  4. Record toppings, sauces, cooking fat, sides, and substitutions that the selected description does not name.

Decision support from the exact records on this page

Turn source data into a better next decision

These conclusions and reading paths are computed from 7 exact records behind Onions source-record guide. Links are chosen by record identity, controlled contrast, formulation input, nutrient spread, or serving context—not by loose keyword similarity.

Equal-weight result

Onions, green, cooked is higher in sodium per 100 g

Onions, green, cooked reports 161 mg versus 1 mg for Onions, for use on a sandwich: a 160 mg difference when both are normalized to 100 g.

Inspect the underlying evidence

The denominator changes the answer

Onions, green, cooked is denser; Onions, cooked, no added fat is higher in its source amount

Onions, green, cooked reports 63 kcal per 100 g and 9 kcal in USDA source amount (15 g). Onions, cooked, no added fat reports a lower 47 kcal per 100 g but a higher 49 kcal in USDA source amount (105 g).

Choose the record before reading the number

Onions, cooked, fat added and Onions, raw are not interchangeable

The page keeps both records at the same 100 g denominator and makes Preparation wording (No matching controlled term in the source name versus raw) the explicit record-description contrast. It does not show that the wording difference caused a nutrient difference. Pick the description that matches the food in front of you rather than averaging away the distinction.

Inspect the underlying evidence

Contextual knowledge graph

Follow the relationship that matches your question

For Onions source-record guide, each path states why the destination belongs here, so you can distinguish a true evidentiary connection from a merely similar label.

Compare two records on this page Onions, cooked, fat added vs Onions, raw

Both records appear in this page’s evidence set. The explicit record-description contrast is Preparation wording: No matching controlled term in the source name versus raw; it is a selection cue, not evidence of cause.

Follow this evidence path Compare two records on this page Onions, cooked, no added fat vs Onions, raw

Both records appear in this page’s evidence set. The explicit record-description contrast is Preparation wording: No matching controlled term in the source name versus raw; it is a selection cue, not evidence of cause.

Follow this evidence path A formulation detail that separates records Salt, table

USDA input 2047 appears in 4 of 7 context records; its summed listed input weight spans 0.3–0.3 g across those source formulations. These are source-formulation input weights, not plated or serving weights. Follow the code to inspect every represented occurrence.

Follow this evidence path A formulation detail that separates records Oil or table fat, NFS

USDA input 81200100 appears in 3 of 7 context records; its summed listed input weight spans 3–3 g across those source formulations. These are source-formulation input weights, not plated or serving weights. Follow the code to inspect every represented occurrence.

Follow this evidence path Put the observed spread in corpus context Sodium: density and serving context

In this page’s records, sodium runs from 1 mg in Onions, for use on a sandwich to 161 mg in Onions, green, cooked, all per 100 g.

Follow this evidence path Put the observed spread in corpus context Iron: density and serving context

In this page’s records, iron runs from 0.2 mg in Onions, cooked, fat added to 1.7 mg in Onions, green, cooked, all per 100 g.

Follow this evidence path 1 context record in this source topic Vegetables on a sandwich

Onions, for use on a sandwich belongs to this USDA source-category collection. Its displayed ranges and complete exact-record catalog provide the peer set for a manual comparison; the destination does not preselect this page’s record.

Follow this evidence path