One teaspoon of instant coffee in a 240 ml cup gives you roughly 60 mg of caffeine. The same cup of drip coffee gives about 95 mg, so instant lands around two thirds of brewed.
Instant against everything else
- Instant, 1 tsp: about 60 mg
- Drip / filter coffee: about 95 mg
- Espresso, single shot: about 63 mg
- Decaf instant: 2 to 4 mg, small but not zero
- 3-in-1 sachets: usually 50 to 70 mg, plus a lot of sugar
Why your cup may be stronger
The variable is you, not the jar. A heaped spoon can be double a level one, and most people at home use more than the label assumes. Two heaped spoons put an instant coffee right next to a filter coffee.
Is instant weaker for a reason?
Partly. Instant is usually made from robusta or a blend, and robusta actually holds more caffeine than arabica. The gap comes from the serving: a spoon of powder is simply less coffee than a full brew basket.
Log it by spoons in Caffy instead of guessing, and your daily total stops being a rough estimate.