Accounting for time doing weight lifting

AngelsFan91106

I use StrongLifts 5x5, which means I only do 3 exercises per workout, with a maximum number of 25 reps per exercise. Each rep takes about, what, 3-5 secs to do, meaning I technically only strength train for five minutes.

So how should I account for weight-lifting time in terms of calculating either TDEE or the MFP calories-burned method?

I have been just using 30 minutes as a general number. But if I can be more precise, I'd like to be.