swiftratings.

Nine ways to understand a rating

Choose your
rating calculator.

Choose the question you want to answer. Each calculator explains its inputs and assumptions.

Calculate my average rating

Enter the number of reviews at each star level.

Calculate average

How many reviews to reach my target?

Find how many five-star reviews you need.

Find target reviews

What will new reviews change?

Try a mix of new star ratings and see the new average.

Simulate new ratings

Combine groups of reviews

Account for different review counts and choose a weight for each group.

Open weighted average

All rating methods

Arithmetic mean

Every review has equal weight. Calculate your average, reach a target or see how new reviews change it.

Open Arithmetic mean

Bayesian estimate

Combine your reviews with an adjustable prior. Estimate a rating, target or new-review scenario.

Open Bayesian estimate

Weighted average

Calculate a star rating with a different weight per review in each group.

Open Weighted average

Time-decay rating

Estimate a rating that gives recent reviews more weight using an adjustable half-life.

Open Time-decay rating

Wilson lower bound

Calculate a conservative ranking score from positive and negative review counts.

Open Wilson lower bound

Trimmed mean rating

Calculate an average after removing an equal share of the lowest and highest ratings.

Open Trimmed mean rating

Mathematical models, clear assumptions

These calculators apply the formulas shown on their pages. Real services may use unpublished weights, review filtering and rounding, so their ratings can differ.

Rating calculation examples