Post-Quantum Signature Bandwidth Calculator
Every post-quantum signature algorithm is larger than the classical ECDSA signatures securing Bitcoin and Ethereum today. That size difference is not a minor implementation detail. It directly determines how much bandwidth and storage a blockchain network needs at a given transaction throughput. This calculator uses the exact byte sizes published in NIST's finalized FIPS 203, 204, and 205 standards, and the FIPS 206 draft, so you can check the real cost yourself rather than take anyone's word for it.
Calculator
How This Is Calculated
The formula is simple and shown in full: bytes per second equals transactions per second multiplied by the signature size of the selected algorithm, in bytes. Data per day is bytes per second multiplied by 86,400 seconds. The multiplier compares each algorithm's daily data volume against ECDSA's 71-byte baseline at the same throughput. Every signature size used here comes directly from a NIST-published standard or draft, linked in the table above.
What This Does Not Model
This calculator is deliberately narrow, and it's worth being explicit about its limits. It calculates raw signature bandwidth only. It does not include transaction metadata overhead beyond the signature itself, such as nonces, addresses, or value fields. It does not model compression, signature aggregation, or state pruning strategies that could reduce real-world storage growth. And it is not a live measurement of any running network. QubitChain.io's testnet has not yet launched, so these are specification-based calculations using published NIST parameter sizes, not observed performance data.
Why QubitChain Uses ML-DSA-65 as Its Baseline
QubitChain.io's block structure and throughput targets, documented in its technical whitepaper, were designed around the ML-DSA-65 baseline shown here from the network's genesis block, rather than retrofitted onto an architecture originally sized for 71-byte ECDSA signatures. That distinction matters: a network built knowing signatures would be roughly 46 times larger than ECDSA's can size its block structure, fee market, and bandwidth budget accordingly from day one. A network retrofitting post-quantum signatures onto infrastructure designed around 71-byte signatures faces a materially harder engineering problem.
Frequently Asked Questions
How much bigger are ML-DSA signatures than ECDSA?
ML-DSA-65, the parameter set QubitChain.io uses by default, produces 3,293-byte signatures compared to ECDSA's 71 bytes, roughly 46 times larger. ML-DSA-44 is about 34 times larger, and ML-DSA-87 is about 65 times larger than ECDSA.
Which post-quantum signature scheme has the smallest size?
Falcon-512 (FN-DSA-512), at 666 bytes, is the most compact of the NIST-standardized post-quantum options, about 9.4 times larger than ECDSA. It comes with a documented implementation tradeoff: Falcon's signing process requires constant-time floating-point arithmetic, which is harder to implement safely than ML-DSA's integer-only operations.
Does this calculator represent QubitChain's live network performance?
No. This is a specification-based calculator using exact byte sizes published in NIST's FIPS 203, 204, 205, and the FIPS 206 draft. QubitChain.io's public testnet has not yet launched, so these are theoretical bandwidth calculations based on the network's designed parameters, not observed live performance data.
Why does signature size matter for blockchain throughput?
Every transaction's signature has to be propagated across the network, verified by every node, and stored permanently in the blockchain's history. Larger signatures directly increase the bandwidth, storage, and state growth required to sustain a given transaction throughput, which is why signature size is a first-order architectural decision for any post-quantum blockchain, not a minor implementation detail.