Free Calculator · Published October 2026
Nitrate Unit Converter: Nitrate-N to the Nitrate Ion
Put the lab unit and the meter unit on the same basis before you compare either one to 10 mg/L as nitrogen.
Built by SubcontractorHub — the software plumbing contractors use to quote, finance, and run every job.
Book a DemoA Nitrate Unit Converter Uses 4.43
This nitrate unit converter follows the factor in University of California Cooperative Extension. The health context of the 10 mg/L public figure is nitrates in well water. Which rules reach a backyard well is private well water regulations.
mg/L or ppm, as the University of California note treats those labels.
Nitrite does not belong in either choice.
Important: All calculator results are ballpark estimates
All calculations are estimates based on historical information and should be verified by the user. This tool is provided as a free service for planning purposes only and is not a substitute for a professional assessment, a supplier quote, or applicable local code requirements.
What the Nitrate Unit Converter Is Using
4.43 from nitrogen to the ion
The extension page says one milligram per liter of nitrate-nitrogen times 4.43 is 4.43 milligrams per liter of nitrate. Ten milligrams per liter as nitrogen is 44.3 as the ion. The tool multiplies and divides by 4.43 exactly so the note matches that page. It does not substitute a longer atomic-weight factor that the extension page did not print. Write both units on the customer record even when they describe the same water. A later visit that reads only the ion will not match a note that stored only the nitrogen. If the sheet is blank, leave it blank. Do not type a nitrite result into this conversion.
Worked examples
The 95 mg/L case is the extension illustration. They rounded 95 divided by 4.43 to 21. This table keeps one decimal.
| Case | As nitrogen | As the ion |
|---|---|---|
| 1 mg/L nitrate-nitrogen | 1 mg/L | 4.4 mg/L |
| 10 mg/L nitrate-nitrogen | 10 mg/L | 44.3 mg/L |
| 95 mg/L nitrate ion | 21.4 mg/L | 95 mg/L |
The public 10 is as nitrogen
EPA's inorganic table lists nitrate at 10 mg/L measured as nitrogen, and nitrite at 1 mg/L measured as nitrogen. The opening of that regulations page says the standards apply to public water systems. A result of 40 mg/L as the ion is 40 divided by 4.43, about 9.0 as nitrogen, which is not above 10. The same digits read as nitrogen would be above 10. The well water testing guide is where nitrate sits on the annual panel. Write the unit next to whichever number you keep.
What to write on the job ticket
The entered value, the direction, both results, and whether the nitrogen-basis figure was above the public 10. Say the factor was 4.43. A water treatment dealer who saves that note will not re-argue the unit on the next visit. Keep the entered number and both results together. A note that says only "nitrate 40" will be read two ways on the next visit. The public comparison stays on the nitrogen basis. This conversion does not size a membrane, does not state a removal percentage, and does not say the well passed a county rule.
Frequently Asked Questions
What does a nitrate unit converter change?
It converts between nitrate-nitrogen and the nitrate ion using 4.43, the factor published by University of California Cooperative Extension. One milligram per liter of nitrate-nitrogen is 4.43 milligrams per liter of nitrate. The reverse is division by 4.43. It does not convert nitrite.
Why do the two nitrate numbers disagree?
Nitrate-nitrogen counts the nitrogen. The nitrate ion counts nitrogen plus oxygen, so the ion number is larger for the same water. A meter and a lab can both be right and still print different units. Compare them only after the conversion.
Is 10 mg/L a private-well limit?
EPA's national primary drinking water regulations list nitrate at 10 mg/L measured as nitrogen. Those regulations apply to public water systems. This tool labels a nitrogen-basis result above 10 so you do not miss the public figure. It does not call a private well illegal.
Does this tool convert nitrite?
No. Nitrite has its own public figure, 1 mg/L as nitrogen, and a different ion factor. Typing nitrite into this nitrate unit converter will mis-state it. Read nitrite on its own line.
Are ppm and mg/L different here?
University of California Cooperative Extension says that at the concentrations used in this kind of measurement, ppm and mg/L are used interchangeably. This page follows that. It does not apply a density correction.
Save the Unit Next to the Lab
Nitrogen basis, ion basis, and the factor you used belong on the customer record.
Get a Free DemoAll calculations are estimates based on historical information and should be verified by the user. This tool is provided as a free service for planning purposes only and is not a substitute for a professional assessment, a supplier quote, or applicable local code requirements. It does not convert nitrite.