The Salinity Converter changes a salinity value stated in parts per thousand into parts per million by multiplying by 1,000 — ppm = ppt × 1,000. Average seawater, at about 35 ppt, therefore contains roughly 35,000 ppm of dissolved salts. The calculator also shows the water-type classification for the result, from fresh water through brackish water and seawater to brine.
An important clarification: in salinity measurement, ppt means parts per thousand (symbol ‰, also called per mille) — grams of dissolved salt per kilogram of water. It does not mean parts per trillion here, even though the same abbreviation is used for parts per trillion in trace-concentration contexts elsewhere on this site. Parts per million (ppm) is the finer scale: milligrams of salt per kilogram of water, used when salinity values need more resolution or must be compared with freshwater standards.
The conversion is routine in aquaculture and marine aquarium keeping, where stocking and treatment decisions hinge on precise salinity, and in estuary and coastal monitoring, where freshwater inflows mix with seawater across the brackish range. Expressing results in ppm also lets marine and brackish measurements sit on the same scale as the TDS and water-quality data collected with standard meters.