New guitarists are often having trouble tuning their guitar by ear. When using
chorder.com's guitar tuner they can tell that the particular string sounds differently than it should, but can't tell if the pitch is higher or lower. Tip: try humming the string note played from our website, than play the same string on your guitar and without stopping humming try to hum the note played on your guitar. If your voice went down you need to tighten that string, if it went up - loosen.
What you should really do is
get a guitar tuner, but you need to know this technique when your tuner is not at hand.