Estimate Firestore costs based on document reads, writes, storage, and bandwidth.
Last verified: May 2026
Both modes share the same pricing. Native mode supports real-time listeners; Datastore mode is for legacy compatibility.
Free tier: 50,000 reads/day. Priced at $0.06 per 100K reads.
Free tier: 20,000 writes/day. Priced at $0.18 per 100K writes.
Free tier: 20,000 deletes/day. Priced at $0.02 per 100K deletes.
Free tier: 1 GB. Priced at $0.18/GB/month.
GCP standard egress pricing: $0.12/GB (first 1 TB), $0.11/GB (1-10 TB), $0.08/GB (10+ TB).
Output will appear here...The GCP Firestore Cost Estimator calculates your expected monthly Firestore bill based on document reads, writes, deletes, stored data volume, and network egress. It supports both Firestore Native mode and Datastore mode pricing, covering the nuances of each. Input your daily operation counts and storage projections to get a granular cost breakdown that separates document operations, storage, and bandwidth charges. This tool is particularly valuable for mobile and web app developers building on Firebase who need to forecast costs before usage scales unexpectedly.
Firestore charges per document read operation. Point reads of a single document, queries that return N documents (charged as N reads), and snapshot listeners that detect changes all count. The free tier includes 50,000 reads per day, after which charges apply per 100,000 additional reads.
Yes. Firestore provides a daily free quota of 50,000 reads, 20,000 writes, 20,000 deletes, 1 GiB of stored data, and 10 GiB of network egress per month. The estimator shows your costs above these free tier thresholds so you can see exactly when paid usage begins.
Your social app's Firestore bill jumped from $40/month to $400/month overnight. The estimator helps you back-solve: with 8,000 daily active users each loading a feed of 50 posts, that's 400K reads/day above the free tier — exactly $400/month at $0.06 per 100K reads. You implement Firestore data caching with `enablePersistence()` on the client and reduce reads by 70% by hitting the local cache for repeat scrolls. Bill drops to $130/month.
The estimator computes Firestore cost as the sum of: (reads/day × 30 / 100K) × $0.06 (after 50K/day free tier), writes × $0.18 per 100K, deletes × $0.02 per 100K, stored data × $0.18/GB/month, and network egress at standard GCP rates. It applies the daily free tier first, so low-volume apps may pay $0 even with significant traffic.
Snapshot listeners (onSnapshot in Web/iOS/Android SDKs) bill 1 read per change event, not 1 read per session. A listener watching a collection of 1,000 documents will charge 1,000 reads on initial subscription, then 1 per change. Teams discover this when their bill spikes after enabling realtime UI features.
Composite indexes are the most common silent cost driver. Each composite index your app creates (or auto-creates) means writes pay extra index-update RUs. Audit firestore.indexes.json regularly and remove indexes for queries you no longer use.
The $1.80 per 1M document read pricing seems cheap until you realize a user scrolling a feed of 500 documents = 500 reads. With 100K daily active users, you're at 50M reads/day = $90/day in reads alone. Pagination + caching are non-optional at scale.
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