It depends on HOW you're "tipping" the streamer.
* If you're doing a direct donation via PayPal (including, but not limited to Stream Labs), the Streamer gets the whole donation, minus any transaction fees imposed by the payment processor. The Streamer can take this money IMMEDIATELY.
* If you're doing a Bit Cheer, the Streamer gets $0.01 / bit cheered (so if you cheer 500 bits, the Streamer gets $5.00). Twitch takes their cut when you purchase bits (at general rate of $1.40 per 100 bits, but provides a discount on bulk orders of 1500 bits / $20 or more), so it's fairly even exchange. HOWEVER, a streamer typically needs to have $100 (10,000 bits) in their account before they can cash out & transaction fees are deducted from their payout. There's also a time-delay for payouts (30 days for Partners & 60 days for Affiliates)
* If you're doing a subscription (for both Partners & Affiliates), Twitch typically does a 50-50 split (so a Lv 1 subscription nets the Streamer $2.50 & so on)... HOWEVER, the split may change depending on the streamer (like 70-30), but this is usually not publicly disclosed. These funds are time-delayed & subjected to transaction fees as well.
* If you're donating via Patreon (which is outside of Twitch), the streamer gets around 85% of your donation. Patreon takes 15% to cover transaction fees & their operating costs.
Hope this helps!