Data coverage is uneven. The United States and a few other countries publish detailed, audited data. Most of the world does not. Where data is thin, this desk shows best estimates from what is available, labeled as estimates, and replaces them when better information is published. Every number carries its source, its date, and one of these tiers. A meter that ticks daily is interpolating from an annual figure unless its tier says LIVE.
Reserves are economically extractable now, at current prices (USGS, January 2026). The meter drains at the 2025 production rate, interpolated to the second. It is a ledger projection, not a measurement. Static lifetime = reserves ÷ 2025 production.
The Energy Institute's proved-reserve totals have not been refreshed since year-end 2020; its methodology is under review. These ratios are 2020 reserves against 2020 production. In 2025 oil, gas, and coal all set production records, so the real ratios are lower.
What is operating, what is in the pipeline, and what could realistically be done. Operating and pipeline entries carry a scale figure with a dated source. The third column is a technician's assessment and is labeled as one.
Figures from single studies and one-off surveys. They do not tick. Each shows its own date.