Convert MCM to BCM
1 million cubic metres (MCM) = 0.001 billion cubic metres (BCM). 1 BCM = 1000 MCM. Example: 15 MCM = 15 × 0.001 = 0.015 BCM.
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1 MCM = 0.001 BCM
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk MCM to BCM converter to paste a column from Excel.
How to Convert MCM to BCM
- 1 MCM = 0.001 BCM
- 1 BCM = 1000 MCM
- Example: convert 15 MCM to BCM: 15 MCM = 15 × 0.001 BCM = 0.015 BCM
Formula
BCM = MCM ÷ 1000
Derivation from SI units:
- 1 MCM = 10⁶ m³ = 1 hm³ (cubic hectometre).
- 1 BCM = 10⁹ m³ = 1000 MCM = 1 km³.
Both units are defined exactly, so the factor is exact. MCM definition: million cubic metres; BCM definition: billion cubic metres.
Worked examples
- A reading of 5 MCM converts to 0.005 BCM.
5 MCM × 0.001 = 0.005 BCM - A value of 100 MCM is 0.1 BCM.
100 MCM × 0.001 = 0.1 BCM
MCM to BCM conversion table
| MCM | BCM |
|---|---|
| 0.1 MCM | 0.0001 BCM |
| 0.5 MCM | 0.0005 BCM |
| 1 MCM | 0.001 BCM |
| 5 MCM | 0.005 BCM |
| 10 MCM | 0.01 BCM |
| 50 MCM | 0.05 BCM |
| 100 MCM | 0.1 BCM |
| 500 MCM | 0.5 BCM |
| 1000 MCM | 1 BCM |
| 10000 MCM | 10 BCM |
Where it's used
MCM are used for CWC weekly reservoir storage bulletins, while billion cubic metres appear in national water resources assessments. Both measure volume of stored or released water (reservoirs, river flows, allocations), so the conversion is a fixed factor.
MCM to other water volume units
| Conversion | 1 MCM equals |
|---|---|
| MCM to BCM | 0.001 BCM |
| MCM to TMC | 0.03531466672 TMC |
| MCM to acre-foot | 810.7131938 acre-ft |
| MCM to cubic metre | 1000000 m³ |
| MCM to Mcft | 35.31466672 Mcft |
| MCM to MAF | 0.0008107131938 MAF |
| MCM to hectare-metre | 100 ha·m |
| MCM to megalitre | 1000 ML |
Show 2 more units
| MCM to cubic kilometre | 0.001 km³ |
|---|---|
| MCM to gigalitre | 1 GL |
Frequently asked questions
How many billion cubic metres are in 1 million cubic metres?
1 MCM = 0.001 BCM.
How do I convert million cubic metres to billion cubic metres?
Multiply the value in MCM by 0.001, or divide it by 1000. For example, 15 MCM × 0.001 = 0.015 BCM.
Is the MCM to BCM conversion exact?
Yes. Both units are defined exactly, and 1 MCM is exactly 0.001 BCM.
Sources
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 4 (derived units) and Table 8 (non-SI units accepted for use with the SI).
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Convert MCM to BCM. Retrieved October 29, 2026, from https://scientificconverters.com/water-volume/mcm-to-bcm/
IEEE
Scientific Converters, "Convert MCM to BCM," scientificconverters.com. Accessed: Oct. 29, 2026. [Online]. Available: https://scientificconverters.com/water-volume/mcm-to-bcm/