Trophic Level Calculator
Calculate energy available at trophic levels using Lindeman's 10% efficiency rule.
Why Only 10% Transfers
Energy passing from one trophic level to the next is heavily depleted. Roughly 90% is lost, and the reasons are worth separating because they are not all the same kind of loss.
| Loss route | What happens | Rough share |
|---|---|---|
| Respiration | Energy burned for metabolism, lost as heat | Largest |
| Not consumed | Bones, wood, roots never eaten | Substantial |
| Not assimilated | Eaten but egested undigested | Varies with diet |
| Death and decay | Passes to decomposers, not to predators | Varies |
Because the losses compound, the reduction is exponential. At 10% efficiency a tertiary consumer receives just 1% of primary production, and a fourth-level predator only 0.1%.
| Trophic level | Share of NPP | Consequence |
|---|---|---|
| 1 — producers | 100% | — |
| 2 — herbivores | 10% | — |
| 3 — carnivores | 1% | Populations much smaller |
| 4 — top predators | 0.1% | Why food chains rarely exceed 5 levels |
This is the fundamental reason food chains are short. Beyond four or five levels there is simply not enough energy to sustain a viable population, regardless of ecosystem productivity.
Why Diet Choice Has Such Leverage
The same arithmetic explains why eating at a lower trophic level supports far more people from the same land. Consuming plants directly captures roughly ten times the energy available from eating animals that ate those plants — the single largest factor in the land footprint of different diets.
Note that the 10% figure is a convenient average, not a constant. Real transfer efficiencies range from about 2% in some terrestrial systems to over 20% in productive marine food webs, where ectotherms waste far less energy maintaining body temperature.
Worked Examples
Common Mistakes
Real efficiencies range from about 2 to 20%. Marine ectotherms transfer far more efficiently than terrestrial endotherms, which spend heavily on thermoregulation.
Pyramids of biomass can be inverted in aquatic systems, where fast-turnover phytoplankton support a larger standing stock of consumers. Energy pyramids never invert.
A large share of energy at every level passes to decomposition rather than upward. Food chain diagrams that omit them misrepresent the flow.
Many species feed at several levels. Omnivores and opportunistic predators occupy fractional trophic positions rather than integer ones.