Penny Rounding

Last 30 days

Uptime

100%

Response time

300 ms typical, 300 ms slowest 5%

Last check

3 h ago

Next check

in 2 h

How to call it

Add it to any MCP client that supports remote servers.

{
  "mcpServers": {
    "penny-rounding": {
      "type": "http",
      "url": "https://penny-rounding.gumballtools.com/api/mcp"
    }
  }
}

3 tools

• round_cash_total

  Settle a transaction under post-penny cash rounding: exact subtotal, tax on the exact subtotal, then round the final total to the nearest nickel — and only for cash. Use this for any "what does X round to" or "what do I owe in cash" question. Four things are wrong in most explan

• rounding_impact

  Compute what cash rounding is actually worth across a list of prices: mean delta per transaction, the up/down/unchanged split, and a per-thousand figure. Use this whenever someone asks whether rounding costs or earns money — a very common question and one usually answered with a

• price_band

  For a list price and a tax rate, find every nearby list price that settles to the SAME cash total, and the highest one. Use this for "what price should I charge" and "can I price to gain from rounding" questions. There is exactly one free move here and it is easy to get backward

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