Cubic Bezier Easing Calculator
Solve a CSS-style cubic Bezier timing curve at an input progress, including the curve parameter, local slope and a progress chart.
YOUR CALCULATION
Result
—
Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Solve the monotonic horizontal Bezier coordinate for t by bisection, then evaluate its vertical coordinate and dy/dx.
B(t)=3(1−t)²tP₁+3(1−t)t²P₂+t³(1,1); solve Bx(t)=input progress
Worked example
The CSS ease control points (0.25,0.1,0.25,1) give output progress about 0.802403 at input progress 0.5. Using t=0.5 directly would give the wrong timing mapping.
Assumptions and input details
Fixed endpoints (0,0) and (1,1). X controls are limited to 0–1; Y may overshoot. The local slope can be undefined at a vertical tangent. This evaluates numerical progress in the entered interval; property clipping, playback scheduling and extrapolation outside 0–1 are excluded.
References: MDN: cubic-bezier timing functions
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.
Evaluate a cubic Bezier curve, its tangent and an approximate length from four control points.
Enter two known points and a target x or y. Calculate the other coordinate, view the straight-line model and clearly distinguish interpolation from extrapolation.
Fit a planar homography to four source/destination point pairs and map a query coordinate with reconstruction residuals.
Reserved advertising space.