Use the estimate provided by the heart rate monitor that was attached to your body and continually measuring your heart rate. Since none of these measures are 100% exact, you may as well always stick with the consistent one (as opposed to using the number spit out by various machines or different estimates from online calculators).
"There's no such thing as failure. There's only feedback. Stop judging yourself & start recognizing it for what it is, an entry point for learning. The truth is, if you're not failing then you're not really reaching & really trying. If you don't like the outcome of a situation, learn from it, make corrections & reapproach wiser & stronger until you achieve your goals."