Tool

Pitch tuner

Mariah
Pick a note, play it, then sing it back.
Tap Start, then sing
FlatOn pitchSharp
Target note
The note you're matching
C4
Last 6 seconds
A steady note is a flat line on the green target.

Hold your phone about an arm's length away and tap Allow when Safari asks for the mic. No sound? Check the silent switch. Nothing is recorded.