Fluid Typography Clamp Calculator
Interpolate a clamped font size between two viewport widths and derive equivalent rem-plus-vw coefficients.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Clamp the affine interpolation to its endpoint sizes and express the intercept using the entered rem reference.
Slope=(sizeHigh−sizeLow)/(widthHigh−widthLow); preferred px=intercept+slope×viewport px
Worked example
16 px at 320 px and 24 px at 1280 px give 20 px at 800 px.
Assumptions and input details
Requires increasing viewport widths and nondecreasing endpoint sizes. Coefficients match the entered root size; changed root font sizing can change browser behavior. No CSS is applied to this page.
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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