Bitcoin Total Supply Calculation

btc_supply.rb

require 'bigdecimal'

def btc(n)
  value = BigDecimal(n) / 1_0000_0000
  a, b = value.to_s('F').split('.')
  "#{a}.#{b.ljust(8, '0')} BTC"
end

BLOCKS_PER_HALVING = 210_000
INITIAL_REWARD = 50_0000_0000

total_supply = 0

(0..).each do |i|
  divisor = 2 ** i

  reward = INITIAL_REWARD / divisor
  break if reward == 0

  halving_total = reward * BLOCKS_PER_HALVING
  old_supply = total_supply
  total_supply += halving_total

  puts "Halving #{i}:"
  puts "  block reward  = 50.00000000 / 2 ^ #{divisor} = #{btc(reward)}"
  puts "  halving total = 210,000 blocks x #{btc(reward)} = #{btc(halving_total)}"
  puts "  total supply  = #{btc(old_supply)} + #{btc(halving_total)} = #{btc(total_supply)}"
  puts
end

puts "Block reward is now 0!"
puts "Final total supply is #{btc(total_supply)}"

output.txt

Halving 0:
  block reward  = 50.00000000 / 2 ^ 1 = 50.00000000 BTC
  halving total = 210,000 blocks x 50.00000000 BTC = 10500000.00000000 BTC
  total supply  = 0.00000000 BTC + 10500000.00000000 BTC = 10500000.00000000 BTC

Halving 1:
  block reward  = 50.00000000 / 2 ^ 2 = 25.00000000 BTC
  halving total = 210,000 blocks x 25.00000000 BTC = 5250000.00000000 BTC
  total supply  = 10500000.00000000 BTC + 5250000.00000000 BTC = 15750000.00000000 BTC

Halving 2:
  block reward  = 50.00000000 / 2 ^ 4 = 12.50000000 BTC
  halving total = 210,000 blocks x 12.50000000 BTC = 2625000.00000000 BTC
  total supply  = 15750000.00000000 BTC + 2625000.00000000 BTC = 18375000.00000000 BTC

Halving 3:
  block reward  = 50.00000000 / 2 ^ 8 = 6.25000000 BTC
  halving total = 210,000 blocks x 6.25000000 BTC = 1312500.00000000 BTC
  total supply  = 18375000.00000000 BTC + 1312500.00000000 BTC = 19687500.00000000 BTC

Halving 4:
  block reward  = 50.00000000 / 2 ^ 16 = 3.12500000 BTC
  halving total = 210,000 blocks x 3.12500000 BTC = 656250.00000000 BTC
  total supply  = 19687500.00000000 BTC + 656250.00000000 BTC = 20343750.00000000 BTC

Halving 5:
  block reward  = 50.00000000 / 2 ^ 32 = 1.56250000 BTC
  halving total = 210,000 blocks x 1.56250000 BTC = 328125.00000000 BTC
  total supply  = 20343750.00000000 BTC + 328125.00000000 BTC = 20671875.00000000 BTC

Halving 6:
  block reward  = 50.00000000 / 2 ^ 64 = 0.78125000 BTC
  halving total = 210,000 blocks x 0.78125000 BTC = 164062.50000000 BTC
  total supply  = 20671875.00000000 BTC + 164062.50000000 BTC = 20835937.50000000 BTC

Halving 7:
  block reward  = 50.00000000 / 2 ^ 128 = 0.39062500 BTC
  halving total = 210,000 blocks x 0.39062500 BTC = 82031.25000000 BTC
  total supply  = 20835937.50000000 BTC + 82031.25000000 BTC = 20917968.75000000 BTC

Halving 8:
  block reward  = 50.00000000 / 2 ^ 256 = 0.19531250 BTC
  halving total = 210,000 blocks x 0.19531250 BTC = 41015.62500000 BTC
  total supply  = 20917968.75000000 BTC + 41015.62500000 BTC = 20958984.37500000 BTC

Halving 9:
  block reward  = 50.00000000 / 2 ^ 512 = 0.09765625 BTC
  halving total = 210,000 blocks x 0.09765625 BTC = 20507.81250000 BTC
  total supply  = 20958984.37500000 BTC + 20507.81250000 BTC = 20979492.18750000 BTC

Halving 10:
  block reward  = 50.00000000 / 2 ^ 1024 = 0.04882812 BTC
  halving total = 210,000 blocks x 0.04882812 BTC = 10253.90520000 BTC
  total supply  = 20979492.18750000 BTC + 10253.90520000 BTC = 20989746.09270000 BTC

Halving 11:
  block reward  = 50.00000000 / 2 ^ 2048 = 0.02441406 BTC
  halving total = 210,000 blocks x 0.02441406 BTC = 5126.95260000 BTC
  total supply  = 20989746.09270000 BTC + 5126.95260000 BTC = 20994873.04530000 BTC

Halving 12:
  block reward  = 50.00000000 / 2 ^ 4096 = 0.01220703 BTC
  halving total = 210,000 blocks x 0.01220703 BTC = 2563.47630000 BTC
  total supply  = 20994873.04530000 BTC + 2563.47630000 BTC = 20997436.52160000 BTC

Halving 13:
  block reward  = 50.00000000 / 2 ^ 8192 = 0.00610351 BTC
  halving total = 210,000 blocks x 0.00610351 BTC = 1281.73710000 BTC
  total supply  = 20997436.52160000 BTC + 1281.73710000 BTC = 20998718.25870000 BTC

Halving 14:
  block reward  = 50.00000000 / 2 ^ 16384 = 0.00305175 BTC
  halving total = 210,000 blocks x 0.00305175 BTC = 640.86750000 BTC
  total supply  = 20998718.25870000 BTC + 640.86750000 BTC = 20999359.12620000 BTC

Halving 15:
  block reward  = 50.00000000 / 2 ^ 32768 = 0.00152587 BTC
  halving total = 210,000 blocks x 0.00152587 BTC = 320.43270000 BTC
  total supply  = 20999359.12620000 BTC + 320.43270000 BTC = 20999679.55890000 BTC

Halving 16:
  block reward  = 50.00000000 / 2 ^ 65536 = 0.00076293 BTC
  halving total = 210,000 blocks x 0.00076293 BTC = 160.21530000 BTC
  total supply  = 20999679.55890000 BTC + 160.21530000 BTC = 20999839.77420000 BTC

Halving 17:
  block reward  = 50.00000000 / 2 ^ 131072 = 0.00038146 BTC
  halving total = 210,000 blocks x 0.00038146 BTC = 80.10660000 BTC
  total supply  = 20999839.77420000 BTC + 80.10660000 BTC = 20999919.88080000 BTC

Halving 18:
  block reward  = 50.00000000 / 2 ^ 262144 = 0.00019073 BTC
  halving total = 210,000 blocks x 0.00019073 BTC = 40.05330000 BTC
  total supply  = 20999919.88080000 BTC + 40.05330000 BTC = 20999959.93410000 BTC

Halving 19:
  block reward  = 50.00000000 / 2 ^ 524288 = 0.00009536 BTC
  halving total = 210,000 blocks x 0.00009536 BTC = 20.02560000 BTC
  total supply  = 20999959.93410000 BTC + 20.02560000 BTC = 20999979.95970000 BTC

Halving 20:
  block reward  = 50.00000000 / 2 ^ 1048576 = 0.00004768 BTC
  halving total = 210,000 blocks x 0.00004768 BTC = 10.01280000 BTC
  total supply  = 20999979.95970000 BTC + 10.01280000 BTC = 20999989.97250000 BTC

Halving 21:
  block reward  = 50.00000000 / 2 ^ 2097152 = 0.00002384 BTC
  halving total = 210,000 blocks x 0.00002384 BTC = 5.00640000 BTC
  total supply  = 20999989.97250000 BTC + 5.00640000 BTC = 20999994.97890000 BTC

Halving 22:
  block reward  = 50.00000000 / 2 ^ 4194304 = 0.00001192 BTC
  halving total = 210,000 blocks x 0.00001192 BTC = 2.50320000 BTC
  total supply  = 20999994.97890000 BTC + 2.50320000 BTC = 20999997.48210000 BTC

Halving 23:
  block reward  = 50.00000000 / 2 ^ 8388608 = 0.00000596 BTC
  halving total = 210,000 blocks x 0.00000596 BTC = 1.25160000 BTC
  total supply  = 20999997.48210000 BTC + 1.25160000 BTC = 20999998.73370000 BTC

Halving 24:
  block reward  = 50.00000000 / 2 ^ 16777216 = 0.00000298 BTC
  halving total = 210,000 blocks x 0.00000298 BTC = 0.62580000 BTC
  total supply  = 20999998.73370000 BTC + 0.62580000 BTC = 20999999.35950000 BTC

Halving 25:
  block reward  = 50.00000000 / 2 ^ 33554432 = 0.00000149 BTC
  halving total = 210,000 blocks x 0.00000149 BTC = 0.31290000 BTC
  total supply  = 20999999.35950000 BTC + 0.31290000 BTC = 20999999.67240000 BTC

Halving 26:
  block reward  = 50.00000000 / 2 ^ 67108864 = 0.00000074 BTC
  halving total = 210,000 blocks x 0.00000074 BTC = 0.15540000 BTC
  total supply  = 20999999.67240000 BTC + 0.15540000 BTC = 20999999.82780000 BTC

Halving 27:
  block reward  = 50.00000000 / 2 ^ 134217728 = 0.00000037 BTC
  halving total = 210,000 blocks x 0.00000037 BTC = 0.07770000 BTC
  total supply  = 20999999.82780000 BTC + 0.07770000 BTC = 20999999.90550000 BTC

Halving 28:
  block reward  = 50.00000000 / 2 ^ 268435456 = 0.00000018 BTC
  halving total = 210,000 blocks x 0.00000018 BTC = 0.03780000 BTC
  total supply  = 20999999.90550000 BTC + 0.03780000 BTC = 20999999.94330000 BTC

Halving 29:
  block reward  = 50.00000000 / 2 ^ 536870912 = 0.00000009 BTC
  halving total = 210,000 blocks x 0.00000009 BTC = 0.01890000 BTC
  total supply  = 20999999.94330000 BTC + 0.01890000 BTC = 20999999.96220000 BTC

Halving 30:
  block reward  = 50.00000000 / 2 ^ 1073741824 = 0.00000004 BTC
  halving total = 210,000 blocks x 0.00000004 BTC = 0.00840000 BTC
  total supply  = 20999999.96220000 BTC + 0.00840000 BTC = 20999999.97060000 BTC

Halving 31:
  block reward  = 50.00000000 / 2 ^ 2147483648 = 0.00000002 BTC
  halving total = 210,000 blocks x 0.00000002 BTC = 0.00420000 BTC
  total supply  = 20999999.97060000 BTC + 0.00420000 BTC = 20999999.97480000 BTC

Halving 32:
  block reward  = 50.00000000 / 2 ^ 4294967296 = 0.00000001 BTC
  halving total = 210,000 blocks x 0.00000001 BTC = 0.00210000 BTC
  total supply  = 20999999.97480000 BTC + 0.00210000 BTC = 20999999.97690000 BTC

Block reward is now 0!
Final total supply is 20999999.97690000 BTC