Tea has three variables that matter and one that does not. The three are how much leaf, how hot the water, and how long it sits. The one that does not is how confidently the packet says "one teaspoon per cup", because a teaspoon is a volume and tea leaves vary enormously in density. This tea brewing calculator works in grams and millilitres, scales the whole thing to however many cups you are actually making, and adjusts the time when you re-steep the same leaf.
Arb Digital publishes this alongside our coffee ratio calculator, and the two are deliberately different tools rather than one with a dropdown. Coffee brewing is a dose-to-water ratio problem: get the grams-per-litre right and the rest follows. Tea adds two outputs coffee does not have, because water temperature is genuinely type-dependent and because the same leaf is routinely brewed several times, each infusion needing a different duration. Those two extras are what this page exists for.
What This Tea Brewing Calculator Does
It takes a tea type, a cup count and a cup size, and returns four numbers: the leaf weight in grams, the volume of water to heat, the water temperature in both Celsius and Fahrenheit, and the steep time in minutes and seconds. A strength selector moves the leaf weight up or down, an infusion selector stretches the time for second, third and fourth steeps, and a small allowance accounts for the water that wet leaves and a cold pot keep for themselves.
The leaf ratio has a genuine standard behind it. ISO 3103:2019, Tea — Preparation of liquor for use in sensory tests, specifies weighing 2 grams of tea per 100 millilitres of water for the standardised tasting method used in professional evaluation. That 2 percent ratio is the baseline this tool uses at standard strength, and it scales linearly with volume.
The temperatures and times are a different kind of number and the page is explicit about that. They are widely published brewing conventions for each tea type, not standards, and reasonable sources differ by five degrees or half a minute. They are shown as bands rather than single values for exactly that reason.
How to Use It
- Pick the type. This sets the temperature band and the time band. Green and white sit well below boiling; black, pu-erh and herbal infusions want water at or near it.
- Set cups and cup size in millilitres. Measure a mug once by filling it from a jug. Most people's "cup" is 280 to 330 ml, not 240.
- Choose a strength. Standard is the ISO ratio. Light and strong move the leaf weight, which is the honest way to change strength.
- Say which infusion this is. The second and later steeps on the same leaf get progressively longer times.
- Weigh the leaf, heat the water, set a timer. Then taste and adjust the strength setting next time rather than the clock.
The Formula and How It's Calculated
Liquor volume is cups times cup size. Water to heat is that volume divided by one minus the loss fraction, so an eight percent allowance on 960 ml of finished tea means heating 960 ÷ 0.92 = 1,043 ml. Leaf weight is the liquor volume in millilitres divided by 100, times 2 grams, times the strength multiplier.
Temperature is the midpoint of the published band for the type, and the tool shows the full band beneath. Fahrenheit is the usual conversion, Celsius times nine fifths plus thirty-two. Steep time is taken from the type's band at the position you choose, then multiplied by an infusion factor of 1 plus 0.35 for each infusion after the first — a common convention reflecting that the most soluble compounds leave the leaf first, so later steeps need longer to reach comparable strength.
Work the defaults through. Four cups at 240 ml is 960 ml of tea. At standard strength that is 960 ÷ 100 × 2 = 19.2 g of leaf. Black tea's published band is 95 to 100 °C, so the midpoint is 97.5 °C, which is 207.5 °F. The time band is 3 to 5 minutes and the middle of it is 4 minutes. A second infusion of the same leaf would run 4 × 1.35 = 5 minutes 24 seconds, and a third 4 × 1.70 = 6 minutes 48 seconds. With the eight percent allowance you would heat about 1,043 ml of water.
The Bands This Tool Uses
Green tea brews at 70 to 80 °C for 2 to 3 minutes. White tea at 75 to 85 °C for 3 to 5 minutes. Oolong at 85 to 95 °C for 3 to 5 minutes. Black tea at 95 to 100 °C for 3 to 5 minutes. Ripe pu-erh at 95 to 100 °C for 3 to 5 minutes. Herbal infusions and tisanes at full boil, 100 °C, for 5 to 7 minutes, because most are dried flowers, roots and fruit rather than Camellia sinensis and need harder extraction.
There is measurement work behind the green tea end of this. A study of Longjing, Elucidating the effect of brewing temperature on the sensory quality of Longjing tea based on multi-scale molecular sensory science, brewed the same tea at 70, 80, 90 and 100 °C and found that the umami and mellow character was strongest at 70 °C and declined as temperature rose, while bitterness and astringency increased sharply towards 100 °C. That is the reason green tea has a lower band, stated as a measured result rather than as folklore.
Temperature and time trade off against each other, but not symmetrically. Work on hot water extraction from tea leaves, published as Hot Water Extraction of Antioxidants from Tea Leaves—Optimization of Brewing Conditions for Preparing Antioxidant-Rich Tea Drinks, tested temperatures from 25 to 100 °C and times from 5 minutes to 12 hours, and found extraction responded strongly to both. Longer at a lower temperature is not the same drink as shorter at a higher one, which is why this tool moves them together rather than letting you trade one for the other.
Why Teaspoons Fail and Grams Do Not
The instruction on almost every packet is one teaspoon per cup. It survives because it is easy, not because it is accurate. Tightly rolled gunpowder green tea and compressed pu-erh pack a teaspoon densely; large-leaf white peony, whole-leaf Darjeeling and most herbal blends are mostly air. The weight of a level teaspoon across those can vary by a factor of three, which means the same instruction produces a drink three times stronger for one tea than another.
A cheap kitchen scale that reads to 0.1 g removes the problem entirely and costs less than a good tin of tea. Weigh once, note the number for the tea you drink most, and you can go back to spooning it with a spoon you have calibrated for that specific tea. This is the same reasoning that makes serious baking work in grams, and the same reason our sourdough hydration calculator and baker's percentage calculator never mention cups.
Re-Steeping, and When It Stops Being Worth It
Whole-leaf teas are built for multiple infusions. The compounds that make tea taste of anything do not all leave at the same rate: the smallest and most soluble come out fastest, which is why a second infusion at the same time is thinner and often sweeter than the first. Extending the time compensates, up to a point.
Where that point sits depends on the leaf. A good oolong or a ripe pu-erh will give four or five worthwhile infusions and change character each time. A fine broken-leaf black tea in a bag is largely spent after one, because the small particle size means extraction was nearly complete in the first three minutes. That is not a quality judgement about bags — it is geometry. Smaller pieces have more surface per gram and give everything up faster.
The practical rule is to re-steep by taste rather than by rule. If infusion three tastes of hot water with a hint of tea, stretching it to eight minutes will mostly add astringency. Start a fresh pot instead.
Water, Vessels and the Things This Tool Ignores
Two variables sit outside the calculator and both are real. The first is water. Hard water changes how tea tastes and how much of the leaf ends up dissolved, which is why the same tea can taste different in two cities. If your tea tastes flat and looks cloudy on cooling, water is the first suspect.
The second is thermal mass. A cold ceramic pot can drop freshly boiled water by ten degrees or more before the leaf has done anything, which quietly turns a black tea brew into an oolong brew. Warming the pot first is not a ritual; it is the difference between the temperature you set and the temperature the leaf actually meets. If you are working towards a serving temperature at the table rather than at the pot, that heat loss continues in the cup.
Caffeine content is deliberately absent from this page. It varies with cultivar, growing conditions, leaf grade, water temperature and steep time, and any single figure would be a guess dressed as data. If you are planning drinks for a group rather than a pot, our party drink calculator handles quantities across a whole event, and the water intake calculator covers plain hydration arithmetic.
Arb Digital builds content and tools that bring buyers to product pages instead of to a competitor's recipe blog.
See Content Marketing Talk To Our TeamCommon Mistakes to Avoid
- Measuring leaf by the spoon — leaf density varies threefold between styles, so the same spoonful is a different dose every time.
- Pouring boiling water on green tea — measured work shows bitterness and astringency climb steeply above 80 °C while umami character falls away.
- Steeping longer to make tea stronger — past the band, extra time mostly adds astringency. More leaf is the controllable lever.
- Forgetting the pot drinks first — wet leaf and an unwarmed pot keep several percent of your water and a good chunk of your heat.
- Assuming your mug holds a cup — most mugs are 280 to 330 ml, so a four-mug pot needs a third more leaf than a four-cup one.
Related Free Tools From Arb Digital
Get coffee dose and water right with the coffee ratio calculator, work out what a daily habit costs with the coffee cost calculator, plan drinks for a whole event with the party drink calculator, size a holiday menu with the Thanksgiving dinner calculator, or handle plain fluid arithmetic with the water intake calculator. The free online tools hub lists everything we publish.
Frequently Asked Questions
The ISO standard method for sensory testing uses 2 grams of tea per 100 millilitres of water. For a 240 millilitre cup that is about 4.8 grams, and for a 300 millilitre mug about 6 grams.
Published conventions put green tea at 70 to 80 degrees Celsius. A study of Longjing brewed at 70, 80, 90 and 100 degrees found umami character strongest at 70 and bitterness and astringency rising sharply as temperature increased.
The commonly published band is 3 to 5 minutes with water at 95 to 100 degrees Celsius. This tool defaults to the middle of that band, at 4 minutes.
This tool adds 35 percent per infusion after the first, so a 4 minute first steep becomes about 5 minutes 24 seconds on the second and 6 minutes 48 seconds on the third. It is a convention, and tasting beats it.
Because a teaspoon is a volume. Rolled gunpowder green and fluffy white peony can differ threefold in weight per spoon, so the same instruction produces very different strengths for different teas.
Wet leaf holds water and an unwarmed pot absorbs some. The default allowance of 8 percent covers that, so heating 1,043 millilitres yields roughly 960 millilitres in the cups.
They use a different band. Most tisanes are dried flowers, roots or fruit rather than tea leaves, so they are steeped at a full boil for 5 to 7 minutes to extract properly.
No. Caffeine varies with cultivar, leaf grade, growing conditions, water temperature and steep time, so any single figure would be a guess rather than a measurement.
This page is a brewing reference for general information. It makes no health claims about tea of any kind, and anyone with a question about caffeine or any ingredient in relation to their own health should speak to a qualified clinician or registered dietitian.
