Water conductivity & TDS converter

The browser tool runs free on your device; the prepaid API charges $0.002 per successful item when pipelines need the same contract from servers and automation.

Supported units and how the conversion is computed

Friendly aliases such as microsiemens per centimeter, millisiemens, decisiemens per meter, siemens per meter, micromhos, parts per million, milligrams per liter, parts per thousand, grains per gallon, and grain/gallon are normalized case-insensitively so forms and APIs can pass either short codes or full names. Within the conductivity family every request multiplies the input by the exact microsiemens-per-centimeter factor for the source, then divides by the factor for the target: one millisiemens per centimeter is exactly one thousand microsiemens per centimeter, one decisiemens per meter equals one millisiemens per centimeter, one siemens per meter is ten thousand microsiemens per centimeter, and one micromho per centimeter equals one microsiemens per centimeter by definition. Within the TDS family the base is parts per million: milligrams per liter equal ppm for dilute aqueous solutions, one part per thousand is one thousand ppm, and one grain per gallon is exactly 17.1 ppm under the conventional US water-treatment identity used by this endpoint.

Request shape, response fields, and unknown-unit errors

The error message names the bad field and lists the supported set so clients can correct forms without guessing. Zero converts cleanly to zero in every target unit. Send a JSON body with three required fields: value as a finite non-negative number, from as the source unit string, and to as the target unit string. Optional factor (aliases tds_factor and k) supplies the EC-to-TDS scale when families differ; it is ignored for pure same-family work and defaults to one half when omitted. Aliases amount and quantity are accepted for value; unit_from and source for from; unit_to and target for to. On success the response echoes the canonical from and to codes, human-readable from_label and to_label strings, from_family and to_family tags, the converted result, intermediate ec_us_cm and tds_ppm quantities when applicable, the factor used for cross-family conversion or null within one family, a dimensionless conversion_factor for same-family pairs, the fixed gpg_ppm constant 17.1, a short formula line suitable for UI display, the method tag conductivity_si, tds_conventional, or ec_tds_scale, and the fixed list of units_supported. Missing value, non-finite numbers such as NaN or Infinity, negative values, missing unit fields, non-positive factor, and any token that does not map to a supported unit fail with invalid_input and are not charged after the engine rejects the request. Identical inputs always yield identical JSON because the path is pure arithmetic with no randomness, no remote lookup, and no dependence on the wall clock, which makes the endpoint safe to pin in continuous-integration goldens and SDK contract tests. Extreme magnitude pairs remain well-defined as long as IEEE double precision can represent the intermediate product.

Browser use, API pricing, and everyday workflows

Switch to the prepaid API when a water-treatment SCADA plugin, greenhouse controller, pool chemistry app, aquarium logger, environmental LIMS, or compliance pipeline must convert conductivity and dissolved solids at scale under a stable KIT contract at $0.002 per successful item; validation failures that raise invalid_input do not consume balance after rejection. Pair this endpoint with general unit converters when a product pipeline needs length or volume families as well, or call it alone when search traffic is specifically for water conductivity and TDS conversion—microsiemens, millisiemens, parts per million, and grains per gallon—rather than a general unit switchboard.