AGL — Above Ground Level (height above terrain).
MSL — Mean Sea Level (absolute elevation).
On sectional charts: all altitudes MSL unless in parentheses — (12) means 1 200 ft AGL.
Add 00 to the printed number.

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Parens = AGL. No parens = MSL. Always add 00. So 70/30 = 7000/3000 MSL; (12) = 1200 AGL.

airspace/msl-vs-agl