Utilities

A few of the questions this blog keeps returning to come down to arithmetic: how a trait passes from parents to offspring, how concentrated a market is, what a tonne of methane counts for, whether old seed is still worth sowing, how much carbon sits in a field. Each tool below shows its formula and its sources, and runs in your browser; nothing you type is sent anywhere.

• Punnett square calculatorEnter two parents' genotypes and the tool draws the Punnett square, then counts the genotype and phenotype ratios of their offspring. It handles up to four genes, ABO blood groups and X-linked traits.
• HHI calculator: Herfindahl-Hirschman Index and merger testEnter each firm's market share, or its sales, and the tool returns the Herfindahl-Hirschman Index, the four-firm concentration ratio and what a merger between two of the firms would do to the index.
• CO2e calculator: convert methane and other gases to CO2 equivalentEnter an amount of a greenhouse gas and the tool converts it to CO2 equivalent, using global warming potentials from the IPCC's Sixth or Fifth Assessment Report. It also turns tonnes of carbon into tonnes of CO2.
• Seed germination calculator and seed viability chartEnter how many seeds sprouted in a germination test and the tool gives your germination rate, the seeds to sow per hole and the seeds to sow for the plants you want. A chart shows how long common vegetable seeds usually keep.
• Soil carbon calculator: from organic matter to tonnes of carbonEnter the organic matter figure from a soil test and the tool converts it to organic carbon, then to the tonnes of carbon, and of CO2, stored per hectare or acre in the layer you sampled.