Which Shockwave? Your answer will vary depending on this.
- G1 Shockwave: Very difficult to tell since he never really stayed a consistent size in any of the comics or the cartoon (but then again, who did?) but if I had to guess I'd say 30-35 or so feet. As for his weight...well that's really tricky but he probably at least weighs 5 tons and probably doesn't weigh more than 50.
- Energon Shockblast: 25-30 feet, he looks kind of short in my opinion, so his weight range is probably 3-30 tons.
- Alternators Shockblast: This I can say with the most certainty due the Alternator line's extreme adherence to scale, he's probably 18-22 feet tall and weighs 1/2-3 tons.
- Animated Shockwave: I'd say 35-50, I say he's taller than his G1 counterpart was due to the fact that he towers over Bulkhead who appears to be 25-30 feet, he probably doesn't weigh much more however because he's significantly skinnier. I can say his height with more certainty due to the increased scale consistency of Animated.
- Shattered Glass: See G1
- Aligned/Prime/War for Cybertron: I really can't say anything other than he's probably 30-40 feet tall and weighs 5-50 tons.
Dark of the Moon: See above, though seeing as how he's supposed to be a "big bad" he's probably going to be on the larger end of that estimate.