Concrete Strength Gain Calculator Track concrete curing strength, estimated MPa gain, and structural readiness using professional engineering standards. ULTRA PRO Select Concrete Grade M20 Concrete M25 Concrete M30 Concrete M35 Concrete M40 Concrete Concrete Age (Days) Temperature Condition Normal Weather Cold Weather Hot Weather Calculate Strength Gain Standard Strength Gain Reference 1 Day 16% 3 Days 40% 7 Days 65% 14 Days 90% 28 Days 99%