Is there anyway to know if you're singing in tune?

Ask someone who ya KNOW doesn't sod about or mince their words, and whom ya can trust to tell ya THE TRUTH, (no matter how rude and harsh it may or may not sound!) Peace and love! Be lucky! :)

Get a free trial version of a pitch detection computer programme such as Musebook Tuner, a microphone/ headset to plug into your computer if you don't already have one (a cheap crappy mic will do for this purpose) and use the tuner to practise hitting and sustaining the right notes.

Well, most people are tone deaf. That's why musical talent is so rare. I would say if you realise that you are out of tune you are not tone deaf. Best way to know if your out of tune is to record yourself singing. When you play it back you'll know straight away. Good singers don't have to think about tuning because their voice automatically hits the note they aim for. That is a rare skill but it doesn't happen by accident. They have probably spent hours practising just like any other musician. Practice = memory = confidence = better ability

If people are covering their ears and screaming for you to shut up that's a fair sign you're out of tune otherwise you're most likley fine or those around you are tone deaf.