You can measure 1 cup of rice without measuring cup.
A kitchen scale will help you to get the quantity of 1 cup of rice even though you don't have a measuring cup.
The following are the measurements of 1 cup of rice in grams using a kitchen scale;
You follow the above measurements in grams if you don't have a measuring cup.
Summary:
250 gram = 250 mililitre.
300 gram = 300 mililitre.
400 gram = 400 mililitre.
500 gram = 500 mililitre.