How much stronger is one earthquake than another?
As of 2 November 2026, USGS figures: each whole step up the magnitude scale means 10 times more ground-motion amplitude and about 32 times more energy, so a magnitude 7 releases about 32 times the energy of a magnitude 6 and about 1,000 times that of a magnitude 5.
Pick two earthquakes
M7 vs M6: about 32× the energy
10× the ground-motion amplitude. Rough TNT equivalent: M6 ≈ 32 thousand tonnes, M7 ≈ 1 million tonnes.
Rule: USGS, "How Much Bigger…?" Calculator, checked 2026-11-02
Rule: British Geological Survey, Earthquake FAQ: What is earthquake magnitude?, checked 2026-11-02
The two rules
- Amplitude (how big the wiggle on a seismogram is): × 10 for every whole step. Ratio = 10difference.
- Energy released: × 31.6 (about 32) for every whole step. Ratio = 101.5 × difference.
- Half a step (6.5 vs 6.0) is about 5.6× the energy, not 1.5×.
- TNT figures here are rough: scaled from the BGS figure that a magnitude 5 is about 1,000 tonnes of TNT.
Worked examplesCommon comparisons
| Compare | Amplitude | Energy | Rough TNT of the larger quake |
|---|---|---|---|
| M5 vs M4 | 10× | 32× | 1 thousand tonnes |
| M6 vs M5 | 10× | 32× | 32 thousand tonnes |
| M7 vs M6 | 10× | 32× | 1 million tonnes |
| M8 vs M7 | 10× | 32× | 32 million tonnes |
| M9 vs M8 | 10× | 32× | 1 billion tonnes |
| M7 vs M5 | 100× | 1,000× | 1 million tonnes |
| M8 vs M6 | 100× | 1,000× | 32 million tonnes |
| M9 vs M6 | 1,000× | 31,600× | 1 billion tonnes |
| M7.4 vs M6.5 | 7.9× | 22× | 4 million tonnes |
| M7.8 vs M7 | 6.3× | 16× | 16 million tonnes |
| M9.1 vs M7.6 | 32× | 178× | 1.4 billion tonnes |
| M6 vs M5.5 | 3.2× | 5.6× | 32 thousand tonnes |
ScaleRough TNT by magnitude
| Magnitude | Energy vs M5 | Rough TNT equivalent |
|---|---|---|
| M3 | 0× | 1 tonnes |
| M4 | 0× | 32 tonnes |
| M5 | 1× | 1 thousand tonnes |
| M6 | 32× | 32 thousand tonnes |
| M7 | 1,000× | 1 million tonnes |
| M8 | 31,600× | 32 million tonnes |
| M9 | 1,000,000× | 1 billion tonnes |
From our archiveFamous earthquakes vs a magnitude 6
| Earthquake | Magnitude | Energy vs M6 |
|---|---|---|
| Indian Ocean Tsunami (2004) | 9.1 | 44,700× |
| Tōhoku Earthquake and Tsunami (2011) | 9.1 | 44,700× |
| Haiyuan Earthquake (1920) | ~8.3 | 2,820× |
| Shaanxi Earthquake (1556) | ~8 | 1,000× |
| Sichuan (Wenchuan) Earthquake (2008) | 7.9 | 708× |
| Great Kantō Earthquake (1923) | 7.9 | 708× |
| Ancash Earthquake and Huascarán Avalanche (1970) | 7.9 | 708× |
| Turkey–Syria Earthquakes (2023) | 7.8 | 501× |
| Tangshan Earthquake (1976) | 7.6 | 251× |
| Kashmir Earthquake (2005) | 7.6 | 251× |
| Manjil–Rudbar Earthquake (1990) | 7.4 | 126× |
| Messina Earthquake and Tsunami (1908) | 7.1 | 45× |
| Haiti Earthquake (2010) | 7 | 32× |
| Bam Earthquake (2003) | 6.6 | 7.9× |
Magnitudes as published in the Global Incident Tracker history archive; "~" marks estimates for quakes before modern instruments.
Related on Global Incident Tracker
Earthquakes today, by city Was that an earthquake? How far away was the earthquake? Earthquakes recorded How many earthquakes happen a day? Drop, cover, hold on
What this page shows, and what it misses
It compares magnitudes, the size of the earthquake at its source. It does not tell you how strongly the ground shook where you were (that is intensity, which depends on distance, depth and soil) or how much damage was done. It does not convert between magnitude scales: agencies now report moment magnitude for large quakes, and old "Richter" numbers cannot be turned into it with a formula.
Ratios from the USGS (public domain). TNT anchor from the British Geological Survey.