21Relay
Bitcoin Utilities

Choose the right tool

Start with everyday calculations, plan a transaction, protect your bitcoin, then move into node and protocol tools.

19

Tools and guides

Free

No account required

Start here

Everyday Bitcoin

Begin with familiar units, regular purchases and simple value comparisons.

3 tools

Start here

Sats Converter

Convert between bitcoin, satoshis and fiat values.

Open tool

Bitcoin DCA Calculator

Model how regular Bitcoin purchases could have performed over time.

Open tool

Sats Purchasing-Power Calculator

Compare sats needed for a manually priced item historically and today.

Open tool

Plan a payment

Transactions and fees

Estimate costs first, understand transaction size, then handle UTXOs and delays.

5 tools

Start here

Fee Estimator

Compare fee rates and estimate the likely cost of an on-chain payment.

Open tool

Transaction Size Calculator

Estimate virtual bytes from address type, inputs, outputs and multisig.

Open tool

Confirmation Time Calculator

Explore probabilistic confirmation windows across block targets.

Open tool

UTXO Consolidation Calculator

Compare consolidating UTXOs during low fees with spending them later.

Open tool

Stuck Transaction Adviser

Check public status, fee priority, RBF signalling and possible CPFP options.

Open tool

Protect your bitcoin

Storage and privacy

Plan custody, inspect public data and prepare for recovery without sharing secrets.

4 tools

Start here

Bitcoin Storage Setup

Compare hardware wallets, signing devices, backups and accessories.

Open tool

UTXO Health Check

Review manual UTXO values for high-fee exposure and privacy trade-offs.

Open tool

Address and Transaction Decoder

Explain a public address or transaction without connecting a wallet.

Open tool

Bitcoin Inheritance Planner

Build a local-only recovery and trusted-person access checklist.

Open tool

Verify for yourself

Node planning and operation

Check readiness, size the setup and move into installation and ongoing operation.

Continue to the Run a Node journey

5 tools

Start here

Node Readiness Check

Review whether your hardware, connection and storage are ready.

Open tool

Node Storage Calculator

Estimate storage required for Bitcoin Core now and over future years.

Open tool

Node Bandwidth Estimator

Estimate initial-sync and ongoing full-node network usage.

Open tool

Node Sync Time Estimator

Estimate initial sync time from internet, SSD, CPU, uptime and mode.

Open tool

Blockchain Growth Tracker

Explore how Bitcoin's blockchain size has grown over time.

Open tool

Go deeper

Mining and protocol

Explore Bitcoin issuance, halvings and the economics of proof-of-work mining.

2 tools

Start here

Bitcoin Supply and Halving Explorer

Explore issued supply, subsidy eras and distance to the next halving.

Open tool

Mining Break-Even Calculator

Compare estimated mining revenue with electricity cost and pool fees.

Open tool

Official links

Node hardware

Compare common routes before buying. 21Relay receives no commission and does not rank these options.

Hardware readiness guide
Existing computerRun Bitcoin Core on supported Windows, macOS or Linux hardware.DIY x86 mini PCBuild a dedicated node using documented umbrelOS-compatible hardware.Raspberry Pi 5Compact DIY hardware for supported node platforms.Umbrel HomeA supported pre-built home server that can run the Bitcoin Node app.Start9 serversPre-built private servers running StartOS and Bitcoin services.myNode hardwarePre-built and DIY routes for the myNode Bitcoin platform.FutureBit ApolloBitcoin-focused home hardware with node and mining configurations.

Calculators provide educational estimates. Review the assumptions shown inside each tool before using a result to make a decision.