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Planck constant

physical constant representing the quantum of action
Thing physical_constant Q122894
Planck constant
Subrat Meher · Public Domain · Wikimedia
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Summary

Planck constant is a physical constant[1]. It ranks in the top 5% of physical constant entities by monthly Wikipedia readership (20,376 views/month).[2]

Key Facts

  • Discoverer or inventor: Max Planck[3]
  • Instance of: UCUM constant[4], action[5]
  • Measured physical quantity: action[6]
  • Named after: Max Planck[7]
  • Place of publication: Royal Prussian Academy of Sciences[8]
  • Commons category: Planck constant[9]
  • Time of discovery or invention: 1901[10]
  • Numeric value: 0.0000000000000000000000000000000006626070040 joule second[11], 0.000000000000000000000000000000000662607015 joule second[12]
  • Different from: reduced Planck constant[13], molar Planck constant[14]
  • Maintained by WikiProject: WikiProject Mathematics[15]
  • P14541: 19aYpw[16]

Why It Matters

Planck constant has Wikipedia articles in 30 language editions, a strong signal of global cultural recognition.[17] It is known by 67 alternative names across languages and contexts.[18]

Related Entities

Albert Einstein Max Planck

References

Programmatic citations — every numbered marker resolves to a verifiable graph row below.

Direct Wikidata claims

  1. [4] ↑ . wikidata.org.
  2. [5] ↑ . wikidata.org.
  3. [3] ↑ . wikidata.org.
  4. [6] ↑ . wikidata.org.
  5. [7] ↑ . wikidata.org.
  6. [8] ↑ . wikidata.org.
  7. [9] ↑ . wikidata.org.
  8. [10] ↑ . wikidata.org.
  9. [11] ↑ . physics.nist.gov. Retrieved . physics.nist.gov. Provenance: wikidata.org.
  10. [12] ↑ . bipm.org. Retrieved . bipm.org. Provenance: wikidata.org.
  11. [13] ↑ . wikidata.org.
  12. [14] ↑ . wikidata.org.
  13. [15] ↑ . wikidata.org.
  14. [16] ↑ . wikidata.org.

Class ancestry

  1. [1] ↑ . Wikidata. wikidata.org.

Aggregate / graph-position facts

  1. [2] ↑ . Wikimedia Foundation. dumps.wikimedia.org.
  2. [17] ↑ . Wikidata sitelinks. wikidata.org.
  3. [18] ↑ . Wikidata aliases. wikidata.org.

📑 Cite this page

Use these citations when quoting this entity in research, articles, AI prompts, or wherever provenance matters. We aggregate Wikidata + Wikipedia + authoritative open-data sources; the stitched, scored, cross-referenced view is what 4ort.xyz contributes.

APA 4ort.xyz Knowledge Graph. (2026). Planck constant. Retrieved October 13, 2026, from https://4ort.xyz/entity/planck-constant
MLA “Planck constant.” 4ort.xyz Knowledge Graph, 4ort.xyz, 13 Oct. 2026, https://4ort.xyz/entity/planck-constant.
BibTeX @misc{4ortxyz_planck-constant_2026, author = {{4ort.xyz Knowledge Graph}}, title = {{Planck constant}}, year = {2026}, url = {https://4ort.xyz/entity/planck-constant}, note = {Accessed: 2026-10-13}}
LLM prompt According to 4ort.xyz Knowledge Graph (aggregator of Wikidata, Wikipedia, and authoritative open-data sources): Planck constant — https://4ort.xyz/entity/planck-constant (retrieved 2026-10-13)

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Edit History

Rolling log of changes to this entity's Wikidata record. Values shown reflect the current state of each edited property — follow the history link to see the precise diff for any edit.

  1. 16d ago · Pruna.ar · 2026-09-29 view diff on Wikidata ↗
    Sitelink count → 85
    Wikipedia languages → ['af', 'an', 'ar', 'as', 'ast', 'az', 'be', 'bg', 'bn', 'bs', 'ca', 'ckb', 'comm
    Place of publication → Royal Prussian Academy of Sciences
    Claims rich → —
    "/* wbsetclaim-create:2||1 */ Place of publication: Royal Prussian Academy of Sciences"
  2. 13w ago · Nyuhn · 2026-07-10 view diff on Wikidata ↗
    Named after → Max Planck
    Local thumb → —
    Measured physical quantity → action
    Discoverer or inventor → Max Planck
    + 8 other properties edited (see Wikidata diff for full list)
    "/* wbeditentity-update:0| */ QuickStatements 3.0 [[:toollabs:qs-dev/batch/40849|batch #40849]]: ZGBK ID"
Live feed via Wikidata EventStreams. New edits appear within minutes of being made on Wikidata.