Coffee Grind Size Guide Calculator: grind, microns and brew time by method
Pick your brew method to get the target grind size in plain words and microns, the brew time it should hit, the usual ratio and water temperature, then enter your actual brew time or taste to see whether to grind finer or coarser.
How it works
Shorter contact time → finer grind · longer contact time → coarser grind · faster than target or sour → grind finer · slower than target or bitter → grind coarser
Grind size controls how fast water extracts flavor, so it is matched to how long the water and coffee stay in contact. Espresso pushes water through in under 30 seconds, so it needs a fine grind (about 180–380 microns) to slow the water and give it enough surface to work on. Pour-over and drip run for a few minutes on a medium grind, French press steeps for four minutes on a coarse grind, and cold brew sits for half a day on the coarsest grind so it does not over-extract. The microns shown are typical ranges from grind charts and overlap, because filters, recipes and grinders differ. Use the brew time as your gauge for methods where the grind sets the flow (espresso, moka, pour-over, drip, AeroPress): if the brew runs fast, grind finer; if it runs slow or chokes, grind coarser. For steeping methods the timer sets the contact time, so fix the steep first. Taste is the final check: sour, thin coffee is usually under-extracted, and bitter, drying coffee over-extracted.
Worked example
A V60 pour-over calls for a medium grind of about 400–700 µm (0.4–0.7 mm, like table sugar to coarse sand) and should finish draining in 2.5–3.5 minutes at about 1:16 with 195–205 °F water. If yours drains in 90 seconds, that is 40% faster than the 2 min 30 s minimum, so grind finer by one or two steps and brew again.
Sources: Honest Coffee Guide: coffee grind size chart (microns by method)
Frequently asked questions
What grind size is right for pour-over?
A medium grind of roughly 400–700 microns, similar to table sugar, targeting a total brew time of about 2.5 to 3.5 minutes. If it drains too fast, grind finer; if it stalls and the bed floods, grind coarser. A Chemex likes it a little coarser.
What grind size is used for espresso?
A fine grind, about 180–380 microns, adjusted until a shot of about 1:2 runs in 25 to 30 seconds. Every grinder and coffee is different, so move in very small steps.
Why does French press need a coarse grind?
The coffee steeps for about four minutes and is pressed through a metal mesh. A coarse grind of about 700–1300 microns slows extraction to match that long contact time and keeps fine particles out of the cup.
My coffee is sour. Should I grind finer or coarser?
Finer. Sour, thin or weak coffee is usually under-extracted, so a finer grind (or a longer brew) pulls out more of the sweet and bitter compounds that balance the acidity. Bitter, harsh coffee calls for coarser.
Should I fix grind or brew time first?
Change one variable at a time. Set your dose and ratio, then use the grind to steer the brew time into the target range for your method, and only then fine-tune by taste.
What are grinder settings in microns?
Microns measure the typical particle size: 1,000 µm is 1 mm. Grinder dials are not standardized, so a setting of 15 on one model is not 15 on another; use the method’s range as a starting point and adjust by taste and time.
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This calculator is for educational purposes. Double-check important results before acting on them.