Petagram to Kilogram Converter

1. Keep Petagrams to kilograms, or pick kg to Pg, or the carbon mode that turns Pg C into Gt CO2.
2. Type the value. For big kilogram figures you can type 5e12 instead of twelve zeros.
3. Read the kilograms, then check the tonnes, gigatonnes and scientific notation cards.

A petagram (symbol Pg) is a metric unit of mass equal to 10^15 grams, or 10^12 kilograms. It joins the SI prefix peta, meaning 10^15, to the gram.

Peta is a newer prefix than most. The NIST prefix history records that peta and exa were added in 1975. The symbol is a capital P, because every multiple prefix from mega upward uses an uppercase letter. A lowercase p means pico, 10^-12, so Pg and pg differ by a factor of 10^27.

One petagram is also one gigatonne. A metric tonne is 10^6 g, NIST calls it the megagram, and 10^15 / 10^6 = 10^9. So 1 Pg = 1 billion tonnes = 1 Gt. NOAA CarbonTracker states it the same way: 1 petagram of carbon is 10^15 g C, or 1 billion metric tons of carbon.

You will rarely weigh anything in petagrams. The unit exists for planet-scale budgets: carbon in the air, the oceans, soils and rocks.

You multiply by 10^12, because peta is 10^15 g, kilo is 10^3 g, and 10^15 / 10^3 = 10^12.

1. Write the petagrams, for example 2.5.
2. Multiply by 10^12. In scientific notation you add 12 to the exponent: 2.5 x 10^0 becomes 2.5 x 10^12.
3. Write it as kg: 2.5 x 10^12 kg, which is 2,500,000,000,000 kg.

For carbon, one more step turns a carbon mass into a CO2 mass. A CO2 molecule weighs 44.009 units for every 12.011 units of carbon it holds, a ratio of about 3.664. NOAA rounds it to 3.67. The scientific notation calculator helps with the exponents.

A single petagram. 1 Pg x 10^12 = 1,000,000,000,000 kg. That is 10^9 t, 1 Gt, or about 2.2 trillion lb.

Permafrost carbon. NASA Earth Observatory gives 1,672 Pg of organic carbon in Northern Hemisphere permafrost. In kilograms that is 1.672 x 10^15 kg, or 1,672 Gt.

A year of emissions as CO2. NOAA CarbonTracker puts fossil fuel emissions at 10.7 Pg C in 2025. Multiply by 44.009 / 12.011 to get about 39.2 Gt CO2.

Reverse. A report lists 5 x 10^12 kg. Divide by 10^12 to get 5 Pg, which is 5 Gt.

Carbon-cycle science uses the petagram of carbon (Pg C) as its standard unit, because the flows are counted in billions of tonnes.

NASA Earth Observatory notes that 10^15 to 10^17 g of carbon, which is 1 to 100 Pg, moves through the fast carbon cycle each year. The CO2 column is our calculation at 44.009 / 12.011. The carbon footprint cost calculator works at household scale, where kilograms and tonnes fit better.

The factor of 10^12 is fixed. What changes the meaning of your number is what the mass refers to.

Carbon or Carbon Dioxide

Pg C counts only the carbon atoms. A mass of CO2 is about 3.664 times larger. Always check which one a report means.

Pg vs Pg

Capital P is peta, 10^15. Lowercase p is pico, 10^-12. A typing slip changes the value by 27 orders of magnitude.

Short Tons in US Text

Some US sources quote tons, meaning 2,000 lb. One petagram is about 1.1 billion short tons, not 1 billion.

Rounded Budget Figures

Carbon budgets are estimates with ranges. A 10.7 Pg C figure carries real uncertainty, so extra decimals after conversion add no accuracy.

A petagram and a gigatonne are the same mass. The teragram and gigagram are smaller steps used for national and city inventories.

For a US pound figure at this scale, the kg to lbs converter takes the kilograms straight across.

Reading Climate and Carbon Reports

NOAA, NASA and global carbon budgets quote Pg C or Gt C. Converting to kg lets you plug the value into SI formulas.

Turning Carbon into CO2

News stories usually quote CO2, while science tables quote carbon. The carbon mode bridges the two.

Physics and Geology Homework

Masses of oceans, ice sheets and rock layers reach petagram scale. Kilograms keep the units consistent in equations.

Each row is computed from 1 Pg = 10^12 kg = 10^9 t = 1 Gt.

1. Using 10^15 for Kilograms

10^15 is the number of grams in a petagram. For kilograms, use 10^12.

2. Treating Pg C as Pg CO2

A carbon mass converted without the 3.664 ratio understates CO2 by almost three quarters.

3. Lowercase Pg

pg is the picogram, a trillionth of a gram. Write the symbol with a capital P.

4. Mixing Gt with Short Tons

A gigatonne uses the metric tonne of 1,000 kg. A US ton is 907.18474 kg.

5. Counting Zeros by Hand

Twelve zeros are easy to miscount. Use scientific notation or the Tonnes card to check.

The mass conversion is exact. The carbon figures and the CO2 ratio are rounded values, so treat them as estimates.

One petagram is exactly 10^12 kg, one trillion kilograms.

Yes. 1 Pg = 10^15 g and 1 Gt = 10^9 tonnes x 10^6 g = 10^15 g, so they are equal.

Pg C means petagrams of carbon. It counts only the carbon atoms, not the whole CO2 molecule.

Multiply by about 3.664, the ratio 44.009 / 12.011. So 2 Pg C is about 7.33 Gt CO2.

There are 10^15 grams, one quadrillion, in a petagram.

One billion kilograms is 0.001 Pg, which is 1 teragram.

Petagrams keep the unit inside the SI gram-based prefix system. The value is identical to gigatonnes, so both appear in reports.

NOAA CarbonTracker gives 10.7 Pg C per year in 2025, up from 6.8 Pg C per year in 2000.

One petagram is about 1.102 billion short tons, since a short ton is 907.18474 kg.

No. The tool runs in your browser and nothing is sent to our servers. Saved results stay in this browser only.

• 1 petagram of carbon is 10^15 g C, or 1 billion metric tons C, plus annual fossil, ocean and land fluxes (NOAA Global Monitoring Laboratory, CarbonTracker CT2026).
• The carbon cycle, with carbon stored in rocks and permafrost and fluxes in petagrams (NASA Earth Observatory).
• Metric SI prefixes, including when peta was added in 1975 (NIST Office of Weights and Measures).
• SI units of mass, including the megagram or metric ton (NIST Office of Weights and Measures).
• SI prefixes table, peta P = 10^15 (BIPM, International Bureau of Weights and Measures).