Online Tool Store
Estimation Calibrator
Estimation Calibrator measures the bias instead of fighting it — multiplying by your own ratio beats trying to estimate more carefully.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Productivity
Estimation Calibrator
Frontend preview — no upload or external service.
Calibration
You estimate 2.3× actual time. Your "quick tasks" are actually your most accurate; complex tasks need +40% buffer.
How the Estimation Calibrator works
- Log the estimate before starting and the actual when finished, without adjusting either afterwards.
- After twenty or so tasks, read your median ratio.
- Apply the multiplier to future estimates rather than attempting to estimate better. The ratio is remarkably stable and much easier to fix than the estimate.
The method
Estimation error is systematic rather than random, and it is nearly always in one direction.
adjusted estimate = raw estimate x personal median ratio
Because the bias is consistent, multiplying by a measured ratio works better than trying harder to estimate accurately.
FAQ
Why not just estimate better?
Because the planning fallacy is robust — people underestimate their own tasks even when they know they usually do, and even when reminded of past overruns. Measuring the bias and correcting for it works where introspection does not.
Why the median rather than the mean?
Because one catastrophic overrun distorts a mean badly. The median describes your typical case, which is what you are applying to a typical future task.
Should the ratio differ by task type?
Usually yes. Familiar work estimates well; novel or dependency-heavy work overruns far more. Separate ratios by type are more useful than one number once you have enough data.
How we compare
| Feature | Online Tool Store | A notes app | A project suite |
|---|---|---|---|
| Personal ratio | ✓ | ✗ | Team average |
| By task type | ✓ | ✗ | ✓ |
| Data stays on device | ✓ | ✗ | ✗ |
| No account needed | ✓ | ✗ | ✗ |
Estimation Calibrator measures the bias instead of fighting it — multiplying by your own ratio beats trying to estimate more carefully.