2.3 TDS Conversion Values

When working with TDS (Total Dissolved Solids) measurements, there is sometimes a need to convert units. Below are a few common measures and conversions to other units. 

1 Grain = 0.0648g (grams) = 64.8mg (milligrams) = 0.00228 oz (ounces) 

Convert grains to grams: multiply grains by 0.0648 grains/gram = grams 

Convert ounces to grams: multiply ounces by 28.35 grams/ounce = grams

Convert grams to mg (milligrams): multiply grams by 1000 mg/g = mg

Convert mg to ppm in a liquid: divide mg into litters = ppm

Convert ppm to ppt: divide ppm by 1000 ppm/ppt = ppt

Or vice-verse:

Convert ppt to ppm: multiply ppt by 1000 ppm/ppt = ppm 

Convert ppm to mg: multiply ppm by litters = mg 

Convert mg to grams: divide by 1000 mg/g = grams 

Convert grams to ounces: divide grams by 28.35 grams/ ounce = ounces 

Convert grams to grains: divide grams by 0.0648 grams/grain = grains

EXAMPLE: Converting grains to ppm and ppt:

5 grains x 0.0648 grains/gram = 0.324 grams

0.324 grams x 1000 mg/g = 324 mg

324 mg ÷ 1 litter = 324 ppm

(if in 2 litters . . . 324 mg ÷ 2 litters = 162 ppm)

(if in 0.5 litters . . . 324 mg ÷ 0.5 litters = 648 ppm)

324 ppm ÷ 1000 ppm/ppt = 0.324 ppt

You may already see the short cut:

0.324 grams in 1 litter = 0.324 ppt (because 1 gram in 1 litter = 1 ppt)

EXAMPLE: Converting ounces to ppm and ppt:

5 ounces x 28.35 grams/ounce = 141.75 grams

141.75 grams x 1000 mg/g = 141,750 mg

141,750 mg ÷ 1 litter = 141,750 ppm

(if in 2 litters . . . 141,750 ÷ 2 litters = 70,875 ppm)

(if in 0.5 litters . . . 141,750 ÷ 0.5 litters = 283,500 ppm)

141,750 ppm ÷ 1000 ppm/ppt = 141.75 ppt

*Information Provided Courtesy of Eutech Instruments Pte Ltd Copyright © 1997