Trophic Level Energy Calculator. In ecology, only a fraction of energy passes from one feeding level to the next — the Trophic Level Energy Calculator measures exactly how much. Enter the Energy at Previous Trophic Level and Energy at Current Trophic Level (in kcal/m²/yr), then select a Transfer Efficiency (5%–20%, or custom) to see your Trophic Efficiency, Energy Transferred, and Energy Lost between levels. Also try the Doubling Time Calculator (Population).
The 10% rule states that only about 10% of energy is transferred from one trophic level to the next. The remaining 90% is lost through metabolic processes, heat production, and other biological functions. See also our Effective Population Size (Ne) — Effective Population Size.
Energy is lost through cellular respiration, heat production, movement, waste products, and incomplete consumption. Organisms use most energy for maintaining their own life processes rather than building biomass.
Trophic efficiency is calculated by dividing the energy at the current trophic level by the energy at the previous trophic level, then multiplying by 100 to get a percentage.
Yes, some ecosystems can have efficiencies up to 20%, particularly in aquatic environments. However, 10% is the general rule used in most ecological calculations.
The lost energy is primarily converted to heat through metabolic processes, used for cellular respiration, lost through waste products, or remains in unconsumed biomass that eventually decomposes.
Energy loss limits the number of trophic levels in an ecosystem. With only 10% efficiency, there's insufficient energy to support more than 4-5 trophic levels in most ecosystems.
Energy transfer refers to the flow of calories or joules between levels, while biomass transfer refers to the actual mass of organic matter. Both follow similar efficiency patterns but are measured differently. You might also find our Chao1 Estimator Calculator useful.