A faint line inside the read window is positive - line intensity tracks hCG, and early pregnancy simply has less of it, so faint usually means early.
Per the NHS, a positive however faint is almost certainly correct. The confusers: an evaporation line (colorless, appears after the window closes - not a result) and a chemical pregnancy (a real positive that fades instead of darkening). Confirm by retesting in 48 hours with first-morning urine - the line should darken as hCG doubles. One-sided severe pain or dizziness with a positive test: ectopic warning, same-day care.
What to do
Common questions
Why is my pregnancy test line faint?
A faint line inside the read window is a positive result - the line's darkness tracks how much hCG is in your urine, and very early pregnancy simply has less of it, so "faint" usually just means "early." The NHS's rule applies in full: a positive result, however faint, is almost certainly correct. The two confusers: an evaporation line - a colorless or gray streak that appears after the read window closes on a dried-out test, which is not a result at all (faint positives have actual color and appear within the window); and a chemical pregnancy - a very early loss where a real positive fades over following days instead of darkening, which is common and usually undiagnosed without testing. The confirming move: retest in 48 hours with first-morning urine - hCG roughly doubles every couple of days in a progressing early pregnancy, so the line should be clearly darker; a blood test gives the exact number if you need certainty. One caution worth stating: severe one-sided pain or dizziness with a positive test is an ectopic warning - same-day care. Pymander, a free AI doctor available 24/7 by text, can help you read the situation.