Cost calculator
Prompt Cache Savings Calculator
Caching is not free: misses pay a write premium on some vendors. Enter your prefix size and hit rate to see net savings, the break-even hit rate, and how every model compares.
Modeled net savings
Calculating…
Results update as you change the inputs.
Methodology and assumptions
Without caching, the prefix is billed at the standard input rate on every request. With caching, hits are billed at the cached-input rate and misses re-write the prefix at the cache-write rate: Anthropic 1.25× input for 5-minute writes or 2× for 1-hour writes, OpenAI's listed cache-write price, and the normal input rate for Gemini and DeepSeek. Gemini explicit caches add storage per million tokens per hour while kept alive; enter 0 hours for implicit caching.
Break-even hit rate = (write − input) ÷ (write − cached read). Reads to break even = ⌈(write − input) ÷ (input − cached read)⌉ per write. Long-context rates apply when prefix + uncacheable tokens exceed a model's threshold. Minimum cacheable prefix lengths, cache eviction, and vendor-specific eligibility rules are not modeled; savings are modeled, not guaranteed. Formula version 2026-10-01.
Official sources:
Pricing last verified:
Official source: Vendor API pricing pages (all listed below)
Frequently Asked Questions
What does the Prompt Cache Savings Calculator calculate?
Caching is not free: misses pay a write premium on some vendors. Enter your prefix size and hit rate to see net savings, the break-even hit rate, and how every model compares.
How accurate is the Prompt Cache Savings Calculator?
It is a planning estimate based on the inputs, formula, assumptions, and sources shown on this page. Actual prices, invoices, taxes, discounts, and outcomes can differ.
Which pricing source does the Prompt Cache Savings Calculator use?
The calculator links to Vendor API pricing pages (all listed below) as its official source. The displayed pricing or reference data was last verified on 2026-10-08.
Are calculator inputs saved or sent to analytics?
Inputs are processed in your browser. Calculator values are not included in analytics events.