---
type: Concept
bundle: cosmology-creation
bundle_version: "0.7.2"
id: mahayuga
title: "Mahāyuga / Caturyuga — महायुग / चतुर्युग"
iast: "Mahāyuga"
devanagari: "महायुग"
description: "The complete four-Yuga cycle (Satya + Tretā + Dvāpara + Kali = 4,320,000 human years) constituting the fundamental unit of cosmic time from which all larger Purāṇic time-scales are built; also called Caturyuga ('four-Yuga cycle') or Divya-Yuga; 1000 Mahāyugas = one Kalpa (day of Brahmā)."
darshana:
  - Purāṇic
school_scope: "Consistent across all major Purāṇas; the 4,320,000-year figure is canonical; minor texts vary individual Yuga durations but the sum is stable"
text_source: "BhP 3.11.18-20; Manu-Smṛti 1.69-71; Viṣṇu Purāṇa 1.3"
tags: [cosmology, time, mahayuga, caturyuga, kalpa, yuga, puranic]
not:
  - term: "Yuga (singular)"
    why: "A Yuga is one of the four ages within the cycle; a Mahāyuga is the complete four-Yuga sequence. 'Yuga' and 'Mahāyuga' are not interchangeable. AI models frequently use 'Yuga' when the text means 'Mahāyuga' (the complete cycle)."
    instead: "Distinguish clearly: 'Kali Yuga' names a specific age within the cycle; 'Mahāyuga' or 'Caturyuga' names the full four-age revolution."
  - term: "one Kalpa"
    why: "A Kalpa equals 1000 Mahāyugas (plus junction periods), not one Mahāyuga. The scale difference is three orders of magnitude: 4.32 million years (Mahāyuga) vs 4.32 billion years (Kalpa). Conflating them collapses the nested hierarchy of Purāṇic time."
related:
  - /concepts/yuga.md
  - /concepts/kalpa.md
  - /concepts/manvantara.md
  - /concepts/kala.md
timestamp: "2026-07-01"
okf_version: "0.2"
license: "CC BY-SA 4.0"
---

# Mahāyuga / Caturyuga — महायुग

**Not:** Yuga (singular), one Kalpa

## The Mathematical Structure

The Mahāyuga (also Caturyuga or Divya-Yuga) is the smallest complete unit of the Purāṇic cosmic calendar:

| Component | Duration |
|-----------|----------|
| Satya Yuga (+ Sandhyās) | 1,728,000 years |
| Tretā Yuga (+ Sandhyās) | 1,296,000 years |
| Dvāpara Yuga (+ Sandhyās) | 864,000 years |
| Kali Yuga (+ Sandhyās) | 432,000 years |
| **Mahāyuga total** | **4,320,000 years** |

The ratio 4:3:2:1 is a precise mathematical structure, not an approximation. The base unit is the Kali Yuga (432,000 years); multiplying by 10 gives the Satya Yuga (4,320,000 = one Mahāyuga). The number 432 and its multiples appear throughout the Purāṇic time-scale.

## The Nesting Hierarchy

The Mahāyuga is the unit from which all larger Purāṇic time-scales are built:

```
1 Mahāyuga = 4,320,000 human years
71 Mahāyugas ≈ 1 Manvantara
1000 Mahāyugas = 1 Kalpa (day of Brahmā)
2 Kalpas = 1 Brahmā-day + night
360 Brahmā-days = 1 Brahmā-year
100 Brahmā-years = Brahmā's lifespan (~311 trillion human years)
```

## Why the Cycle Resets

Each Mahāyuga represents one complete cycle of dharma's rise and decline. After the Kali Yuga ends, a new Satya Yuga begins — not a new universe, but a new cycle within the same Kalpa. The Pralaya at the end of a Kali Yuga is typically the Nitya Pralaya (constant dissolution at the micro-scale) or, if it falls at the end of a Brahmā-day, the Naimittika Pralaya. The Mahā Pralaya occurs only at the end of Brahmā's lifespan (see pralaya.md).

## Audience Metaphor

The Mahāyuga is like a complete musical phrase that repeats throughout a symphony. The Kali Yuga is its final note — not a collapse but a resolution that sets up the next repetition. One thousand of these phrases (Mahāyugas) constitute a single "movement" (Kalpa) of the cosmic symphony, after which a longer rest (Naimittika Pralaya) occurs before the next movement begins.

## Citations

1. Bhāgavata Purāṇa 3.11.18-20 — definitive Mahāyuga duration statement
2. Manu-Smṛti 1.69-71 — Mahāyuga calculation; see references/manusmriti.md
3. Viṣṇu Purāṇa 1.3 — Mahāyuga in the nested time-scale system; see references/vishnu-purana.md
