Potassium mg to mmol Converter (mEq, KCl, mg/dL to mmol/L)

By mmolltomgdl.com Editorial Team · Conversion factor verified 24 September 2026 · How we check

Potassium mg to mmol: divide milligrams by 39.1. 1 mmol of potassium = 39.1 mg = 1 mEq. So 1 g of potassium = 25.6 mmol, and 20 mmol of potassium = 782 mg. For blood tests, potassium mg/dL ÷ 3.91 = mmol/L.

The calculator converts blood potassium (mg/dL ↔ mmol/L). For amounts in food, supplements and potassium chloride (KCl), use the tables below.

Potassium Conversion Factors (mg, mmol, mEq, mg/dL, mmol/L)

Potassium (K) has an atomic mass of 39.10, and it carries a single charge, so mmol and mEq are the same number.

Convert potassium	Formula	Example
mg to mmol	mmol = mg ÷ 39.1	500 mg = 12.8 mmol
mmol to mg	mg = mmol × 39.1	40 mmol = 1,564 mg
g to mmol	mmol = g × 25.6	1 g = 25.6 mmol
mmol to mEq	mEq = mmol (charge 1)	20 mmol = 20 mEq
mg to mEq	mEq = mg ÷ 39.1	391 mg = 10 mEq
KCl g to mmol K	mmol = g KCl × 13.4	1 g KCl = 13.4 mmol
mg/dL to mmol/L (blood)	mmol/L = mg/dL ÷ 3.91	16 mg/dL = 4.09 mmol/L
mmol/L to mg/dL (blood)	mg/dL = mmol/L × 3.91	4.0 mmol/L = 15.6 mg/dL

Potassium mg to mmol Chart

Potassium (mg)	Potassium (mmol)	Potassium (mEq)
39 mg	1.0 mmol	1.0 mEq
99 mg	2.5 mmol	2.5 mEq
100 mg	2.6 mmol	2.6 mEq
200 mg	5.1 mmol	5.1 mEq
250 mg	6.4 mmol	6.4 mEq
300 mg	7.7 mmol	7.7 mEq
400 mg	10.2 mmol	10.2 mEq
500 mg	12.8 mmol	12.8 mEq
1,000 mg	25.6 mmol	25.6 mEq
1,500 mg	38.4 mmol	38.4 mEq
2,000 mg	51.2 mmol	51.2 mEq
2,600 mg	66.5 mmol	66.5 mEq
3,000 mg	76.7 mmol	76.7 mEq
3,400 mg	87.0 mmol	87.0 mEq
3,500 mg	89.5 mmol	89.5 mEq
3,510 mg	89.8 mmol	89.8 mEq
4,000 mg	102.3 mmol	102.3 mEq
4,700 mg	120.2 mmol	120.2 mEq

The World Health Organization recommends at least 3,510 mg of potassium a day for adults, which is about 90 mmol.

Potassium mmol to mg Chart

Potassium (mmol = mEq)	Potassium (mg)	Potassium (g)
1 mmol (1 mEq)	39 mg	0.04 g
2 mmol (2 mEq)	78 mg	0.08 g
5 mmol (5 mEq)	195 mg	0.20 g
8 mmol (8 mEq)	313 mg	0.31 g
10 mmol (10 mEq)	391 mg	0.39 g
15 mmol (15 mEq)	586 mg	0.59 g
20 mmol (20 mEq)	782 mg	0.78 g
25 mmol (25 mEq)	977 mg	0.98 g
30 mmol (30 mEq)	1,173 mg	1.17 g
40 mmol (40 mEq)	1,564 mg	1.56 g
50 mmol (50 mEq)	1,955 mg	1.95 g
60 mmol (60 mEq)	2,346 mg	2.35 g
80 mmol (80 mEq)	3,128 mg	3.13 g
100 mmol (100 mEq)	3,910 mg	3.91 g

Potassium Chloride (KCl): g to mmol

Potassium supplements and IV fluids usually contain potassium chloride (molar mass 74.55 g/mol). One gram of KCl contains 13.4 mmol (mEq) of potassium, or about 524 mg of elemental potassium.

Potassium chloride	Potassium (mmol = mEq)	Elemental potassium (mg)
150 mg KCl	2.0 mmol	79 mg
600 mg KCl	8.0 mmol	315 mg
750 mg KCl	10.1 mmol	393 mg
1 g KCl	13.4 mmol	524 mg
1.5 g KCl	20.1 mmol	787 mg
2 g KCl	26.8 mmol	1,049 mg
3 g KCl	40.2 mmol	1,573 mg

A standard 10 mL ampoule of 15% potassium chloride contains 1.5 g KCl, which is 20 mmol of potassium. Always follow the product label and your prescriber: concentrated potassium must be diluted before use.

Potassium mEq to mmol

For potassium, 1 mEq = 1 mmol, because the potassium ion has a single positive charge. 8 mEq = 8 mmol, 10 mEq = 10 mmol = 391 mg, and 20 mEq = 20 mmol = 782 mg. Blood potassium in mmol/L is the same number as mEq/L.

Potassium % Daily Value to mg

US food labels show potassium as a percentage of the Daily Value (DV), which is 4,700 mg for adults. To convert % DV to mg, multiply 4,700 by the percentage.

% Daily Value	Potassium (mg)	Potassium (mmol)
2% DV	94 mg	2.4 mmol
4% DV	188 mg	4.8 mmol
6% DV	282 mg	7.2 mmol
8% DV	376 mg	9.6 mmol
10% DV	470 mg	12.0 mmol
15% DV	705 mg	18.0 mmol
20% DV	940 mg	24.0 mmol
25% DV	1,175 mg	30.1 mmol
50% DV	2,350 mg	60.1 mmol
100% DV	4,700 mg	120.2 mmol

Blood Potassium: mg/dL to mmol/L

Blood (serum) potassium, often written K on lab reports, is almost always reported in mmol/L or mEq/L. If you have a value in mg/dL, divide by 3.91 to get mmol/L, or use the potassium mmol/L to mg/dL converter for the other direction.

Potassium (mg/dL)	Potassium (mmol/L = mEq/L)
8.0 mg/dL	2.05 mmol/L
10.0 mg/dL	2.56 mmol/L
12.0 mg/dL	3.07 mmol/L
13.7 mg/dL	3.50 mmol/L
14.0 mg/dL	3.58 mmol/L
15.0 mg/dL	3.84 mmol/L
15.6 mg/dL	3.99 mmol/L
16.0 mg/dL	4.09 mmol/L
17.0 mg/dL	4.35 mmol/L
18.0 mg/dL	4.60 mmol/L
19.6 mg/dL	5.01 mmol/L
20.0 mg/dL	5.12 mmol/L
22.0 mg/dL	5.63 mmol/L
23.5 mg/dL	6.01 mmol/L
25.0 mg/dL	6.39 mmol/L

Normal Potassium Levels in Blood (mmol/L)

Serum potassium (K)	mmol/L (mEq/L)	mg/dL
Normal range (adults)	3.5 – 5.0	13.7 – 19.6
Low potassium (hypokalemia)	below 3.5	below 13.7
Severe hypokalemia	below 2.5	below 9.8
High potassium (hyperkalemia)	above 5.0 (some labs 5.5)	above 19.6
Severe hyperkalemia	6.5 or higher	25.4 or higher

A potassium of 3.3–3.4 mmol/L is mildly low, 4.0–4.2 mmol/L is in the middle of the normal range, and 5.2 mmol/L is mildly high. Potassium affects heart rhythm, so abnormal results need medical review. Use the range on your own lab report.

Frequently Asked Questions

How do I convert potassium mg to mmol?

Divide the mg value by 39.1. For example, 1,000 mg of potassium ÷ 39.1 = 25.6 mmol.

How many mmol is 1 g of potassium?

1 g of potassium = 25.6 mmol. 1 g of potassium chloride (KCl) = 13.4 mmol of potassium.

How many mg is 20 mmol of potassium?

20 mmol × 39.1 = 782 mg. 40 mmol = 1,564 mg.

How many mmol is 3,510 mg of potassium?

3,510 mg ÷ 39.1 = 89.8 mmol, the daily amount recommended by the WHO.

Is potassium mmol the same as mEq?

Yes. Potassium has a charge of +1, so 1 mmol = 1 mEq and mmol/L = mEq/L.

How much is 10 mEq of potassium in mg?

10 mEq = 10 mmol = 391 mg of potassium.

What is the potassium conversion factor from mg/dL to mmol/L?

Divide mg/dL by 3.91 (or multiply by 0.256). Multiply mmol/L by 3.91 to get mg/dL.

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