dive-math

Scuba diving math for TypeScript: gas laws, MOD/END, blending, fills, oxygen exposure, gas planning and CCR loop math.

Safety. This library is a reference implementation for education and tooling. It is not a dive computer or a blending certification. Verify every fill and dive plan independently, with training and approved tools.

Install

npm install dive-math

The package is ESM-only, has zero runtime dependencies, and ships its own types.

Requirements

• Node.js 22 or later. CommonJS projects can load it with import(), or with require() (Node 22.12+ loads ES modules synchronously).
• TypeScript 4.7 or later, with moduleResolution set to node16, nodenext or bundler (5.0+). The legacy node/node10 resolution can't see the subpath exports, and a node16 project must itself be ESM ("type": "module" or .mts).
• Bundlers and browsers: works with any bundler (Vite, Next.js, webpack); output is ES2022 (Chrome/Edge 94+, Firefox 93+, Safari 16.4+).

Quick start

import { gas, mod, end, bestMix } from 'dive-math/gas'

mod(gas(0.32), 1.4) // => 33.75
end(gas(0.18, 0.45), 60) // => 28.5
bestMix({ depthM: 60, maxPpo2: 1.4, targetEndM: 30 }).fhe // => 0.4286

Import from the package root for everything, or from a subpath to keep bundles small.

Modules

| Module | Subpath | What it covers | | --------- | --------------------- | --------------------------------------------------------- | | units | dive-math/units | Pressure, depth, volume, flow and temperature conversions | | pressure | dive-math/pressure | Depth/pressure (ATA), water type, gauge/absolute | | altitude | dive-math/altitude | Surface pressure at altitude, theoretical ocean depth | | gas | dive-math/gas | Gas mixes, ppO₂, MOD, END, EAD, best mix | | density | dive-math/density | Gas density and density limits | | real-gas | dive-math/real-gas | Virial compressibility (Z) for O₂, N₂ and He mixes | | cylinders | dive-math/cylinders | Cylinder tables, free gas, tank factor | | equipment | dive-math/equipment | Booster presets and common mixes | | blending | dive-math/blending | Partial-pressure blending, top-up mixes, nitrox stick | | fill | dive-math/fill | Cascade, booster and hot-fill calculations | | oxygen | dive-math/oxygen | CNS and OTU oxygen exposure | | planning | dive-math/planning | SAC/RMV, rock bottom, turn pressures, tank matching | | ccr | dive-math/ccr | Loop ppO₂ and inert fractions, SCR, O₂ cell checks |

Documentation

• Docs site: https://marshallasch.github.io/dive-math/
• Moving from the fill-station math: MIGRATION.md

License

MIT. Real-gas virial coefficients and reference values are derived from GasPlanner (MIT); see THIRD_PARTY_NOTICES.md.