Referring to the previous post, **Calculate Specific Gravity (SG) in oilfield unit **, you get specific gravity (SG) from mud weight (ppg and lb/ft^{3}) and pressure gradient (psi/ft) but you may need to reverse calculation from specific gravity (SG) to mud weight or pressure gradient (psi/ft). So you will learn how to how to convert specific gravity to mud weight (ppg and lb/ft^{3}) and pressure gradient (psi/ft) by using simple formulas as follows:

**1. Convert specific gravity to mud weight in pounds per gallon (ppg)**

Convert specific gravity fomula: mud weight in ppg = specific gravity (SG) x 8.33

Example: specific gravity = 1.50

mud wt, ppg = 1.50 x 8.33

mud wt = 12.5 ppg

**2. Convert specific gravity to mud weight in lb/ft ^{3}**

Convert specific gravity fomula: Mud weight in lb/ft3 = specific gravity x 62.4

Example: specific gravity = 1.50

Mud weight in lb/ft

^{3}= 1.50 x 62.4 lb/ft

^{3}

Mud weight in lb/ft

^{3}= 93.6 lb/ft

^{3}

**3. Convert specific gravity to pressure gradient in psi/ft**

Convert specific gravity fomula: Pressure gradient in psi/ft = specific gravity (SG) x 0.433

Example: specific gravity = 1.5

Pressure gradient in psi/ft = 1.5 x 0.433

Pressure gradient in psi/ft = 0.650 psi/ft

Please also find the Excel sheet regarding how to **convert specific gravity (SG)**

Ref book: Formulas and Calculations for Drilling, Production and Workover, Second Edition

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