It really depends on your entire situation ... but a rule of thumb is 20% of gross income or 30% of net profits.
What are estimated taxes?
https://ttlc.intuit.com/replies/3301588
Do I need to make estimated tax payments to the IRS?
https://ttlc.intuit.com/replies/3301891
Why did 1040-ES estimated tax vouchers print out? Do I need them?
https://ttlc.intuit.com/replies/3301872
How does TurboTax calculate my estimated tax payments?
https://ttlc.intuit.com/replies/3301730