Human civilization is currently somewhere below Type I, as it is able to harness only a portion of the energy that is available on Earth. The current state of human civilization has thus been named Type 0. Although intermediate values were not discussed in Kardashev's original proposal, Carl Sagan argued that they could easily be defined by interpolating and extrapolating the values given above. In 1973, he calculated humanity's civilization type to be 0.7, in relationship to Kardashev's model for Types 0 and I.

Type I — a civilization that is able to harness all of the power available on a single planet — has approximately 10¹⁶ or 10¹⁷ W available. Earth specifically has an available power of 1.74 ×10¹⁷ W (174 petawatts, see Earth's energy budget). Kardashev's original definition was 4 ×10¹² W — a "technological level close to the level presently attained on earth" (presently meaning 1964)

Type II — a civilization that is able to harness all of the power available from a single star, approximately 4 ×10²⁶ W. Again, this figure is variable; the Sun outputs approximately 3.86 ×10²⁶ W. Kardashev's original definition was also 4 ×10²⁶ W.