How much caffeine is in green tea vs. coffee?

So you find yourself wondering if green tea will wake you up just like a nice cup of coffee would. Often a debate occurs between these two drinks. It's an age-old question, a cup of coffee or a lovely green tea, what'll do the job better? While the health benefits differ by a lot and are known to everyone, the caffeine content is something not a lot of people know about. Let's get into it. Now obviously, coffee generally has more caffeine than green tea, but a lot of factors affect this. Actually, it can be the other way round in some cases. For example, brewing methods can affect the caffeine content in a cup of green tea significantly. One major difference is also the fact that coffee's caffeine levels are felt faster than green tea because the latter has L-theanine, which gives a calming feeling. Specifics of the caffeine levels: A cup of coffee will generally have about 80-100 mg of caffeine, while a cup of green tea will have 30-50 mg of caffeine. Now, this can vary as some coffees can have a much higher caffeine content, and other factors can affect a cup of green tea. So which factors are those? 1. Tea- the specific tea you're having could make a huge difference. A lot of varieties are grown to have higher caffeine levels. 2. Harvesting- it's generally believed that when green tea leaves are harvested early, they would have higher caffeine content. This might be hard to find out, but it matters. 3. Temperature- When you brew your tea, using hotter water will lead to more caffeine being extracted into your cup. 4. Brewing time- if you steep your tea for a longer period, it'll have more caffeine. But again, this is related to the temperature of the water. Between a cold brew steeped for longer and a brew made with hotter water, the latter will always have more caffeine. 5. Brewing method- Cold brewing gives a brew less caffeine than a hot brew does. But if you made a hot brew, you can still add ice for higher caffeine levels. Now for some factors that affect caffeine levels in coffee. 1. Coffee species and size of the grind: For example, Arabica has much lower caffeine levels than Robusta. Also, a finer grind size will always extract more caffeine when brewed than a coarse one. 2. Brewing method- Now, when we consider all the different brewing methods, like French press, espresso, drip coffee, or percolator, any brewed coffee will always have more caffeine content. 3. Amount of coffee- More coffee=More caffeine; this one is pretty obvious. 4. Brewing time-similar to tea, more brewing time means more caffeine. This is why cold brews brewed longer can have more caffeine than hot coffee when brewed longer. 5. Temperature-the hotter the temperature, the more caffeine will be extracted. What about decaf? Decaf coffee is a common thing, but did you know it's very hard to find decaf tea. Like decaffeinated coffee, decaffeinated tea isn't completely caffeine-free, but it's quite low. I hope I've answered your question.