diff --git a/include/libcamera/internal/software_isp/swisp_stats.h b/include/libcamera/internal/software_isp/swisp_stats.h
index d9d0d9be8..43ca85b26 100644
--- a/include/libcamera/internal/software_isp/swisp_stats.h
+++ b/include/libcamera/internal/software_isp/swisp_stats.h
@@ -43,6 +43,10 @@ struct SwIspStats {
 	 * \brief A histogram of luminance values of all the sampled pixels
 	 */
 	Histogram yHistogram;
+	/**
+	 * \brief A variance value for the autofocus algorithm
+	 */
+	double variance;
 };
 
 } /* namespace libcamera */
diff --git a/src/libcamera/software_isp/swstats_cpu.cpp b/src/libcamera/software_isp/swstats_cpu.cpp
index 362fb6a86..0d2bbd686 100644
--- a/src/libcamera/software_isp/swstats_cpu.cpp
+++ b/src/libcamera/software_isp/swstats_cpu.cpp
@@ -391,6 +391,7 @@ void SwStatsCpu::startFrame(uint32_t frame)
 
 	for (auto &s : stats_) {
 		s.sum_ = RGB<uint64_t>({ 0, 0, 0 });
+		s.variance = 0.0;
 		s.yHistogram.fill(0);
 	}
 }
@@ -408,9 +409,11 @@ void SwStatsCpu::finishFrame(uint32_t frame, uint32_t bufferId)
 
 	if (valid) {
 		sharedStats_->sum_ = RGB<uint64_t>({ 0, 0, 0 });
+		sharedStats_->variance = 0.0;
 		sharedStats_->yHistogram.fill(0);
 		for (const auto &s : stats_) {
 			sharedStats_->sum_ += s.sum_;
+			sharedStats_->variance += s.variance;
 			for (unsigned int j = 0; j < SwIspStats::kYHistogramSize; j++)
 				sharedStats_->yHistogram[j] += s.yHistogram[j];
 		}