Runs on this device. Inputs are not uploaded or saved. Results rounded for display.
How to use it
- Measure the inputs in the units shown. Keep a note of your original recipe.
- Change the relevant input and calculate. Compare the answer with the worked example below.
- Use the output within the stated limits; reset to restore the example inputs.
Worked example
250 g at 2% to 1.25% requires 150 g water, giving 400 g final beverage.
Assumptions and limits
Use coffee-calibrated refractometer readings, not a water conductivity meter. Assumes added water contributes negligible coffee solids; milk is outside this model.
Questions
What does this result establish?
Conserve dissolved coffee solids: final mass = initial mass × initial TDS / target TDS. It provides the stated arithmetic or random ordering; it is not a taste or equipment certification.
What measurements should I use?
Beverage before dilution (g); Initial coffee TDS (%); Target coffee TDS (%). Keep the units consistent rather than copying a number from a differently labelled recipe.
Why is an input rejected?
Blank, non-finite, negative or out-of-domain measurements cannot produce a valid answer. Each field has a bounded range. Incompatible combinations show an explanation instead of retaining a previous result.
Can I use this without an account?
Yes. Once this page and its modules load, the calculation runs locally without accounts, external APIs or input storage. Reloading restores the defaults.
Related tools
Recipe Batch Scaling
Multiply every ingredient by new water / original water.
Open tool →Iced Pour-Over Water and Ice
Total water = dose × ratio. Ice = total water × ice share. Hot water is the remainder.
Open tool →Staged Pour Planner
Subtract bloom from total water and divide the remaining water into equal additions. Results distinguish added and cumulative weights.
Open tool →