How do you calculate cross-browser support cost?
Supporting more browsers adds a lot of invisible work: CSS vendor prefixes, polyfills, and per-browser QA testing all pile up. This calculator takes your base development time and factors in the number of supported browsers plus legacy browser requirements to estimate the real added effort and cost.
We treat one modern evergreen browser (Chrome, Edge, Firefox, Safari, etc.) as the baseline, and assume each additional browser adds roughly 8% overhead. If you also need to support a legacy browser like IE11, polyfills, transpiling, and separate CSS handling add another 35 percentage points on top.
If the result feels heavy for your budget or timeline, check your actual audience's browser share data and reconsider your support scope. Dropping legacy browsers with negligible market share is often the most cost-effective call.
Frequently Asked Questions
Check your actual audience's browser share first. If a legacy browser is under 1% of traffic, dropping support and reallocating that time is often the more efficient call.
We assume each additional browser adds roughly 8% overhead for testing, polyfills, and CSS fixes. Actual figures vary by project complexity.
Can I Use only tells you feature support status, not the actual time and cost of building and testing for it. This calculator turns that into a schedule and budget estimate.