Free Oil Weight to Volume calculator with clear step-by-step results.
Cooking oils sit around 0.92 g/ml, so 100 grams is closer to 109 millilitres than 100 - an 8-9% error if treated as water. Oils also expand noticeably with heat, which is why the temperature correction is included for anyone measuring warm oil.
Temperature-corrected density
Density = density at 20 C - 0.00064 x (temperature - 20)
Volume
Millilitres = grams / density
Only slightly - the common cooking oils span about 0.914 to 0.925 g/ml, roughly a 1% spread. Temperature has a larger effect over a wide range.
Thermal expansion. Frying oil at 180 C is around 6% less dense than at room temperature, which matters when topping up a fryer by weight.