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Network Error Budget Calculator

Turn an SLO into a concrete error budget in minutes and failed requests, and track the burn rate against it.

About Network Error Budget Calculator

An SLO of 99.9% over 30 days is 43.2 minutes of allowed failure, and the same fraction applied to request volume gives the number of failed requests that fit inside the objective. The burn rate normalises consumption against elapsed time so that 1.0 is on-pace regardless of where you are in the period. Error budgets convert reliability arguments into arithmetic: while budget remains you can ship changes, and when it is gone the answer to a risky change request is no.

Formula

Network Error Budget

error budget = (1 − SLO) × period; allowed failures = (1 − SLO) × requests; burn rate = share of budget spent ÷ share of period elapsed.

1 − SLO
The unreliability you are explicitly allowed
burn rate
1.0 means exactly on pace to exhaust the budget at period end

Worked example

With the default values below, Network Error Budget Calculator returns Error Budget of 43.2. Change any input above and every figure here is recalculated in your browser.

Inputs used

Service level objectiveaccepts 50–100 %
99.9 %
Budget periodaccepts 1–366 days
30 days
Requests in the periodaccepts 1–1,000,000,000,000 requests
500,000,000 requests
Budget consumed so faraccepts 0–500,000 minutes
22 minutes
Period elapsedaccepts 0.1–100 %
50 %

Results

Error Budget
43.2 minutes
Failed Requests Allowed
500,000
Budget Remaining
21.2 minutes
Burn Rate
1.02 × budget pace
Budget Status
Elevated burn — the budget will run out before the period ends

Step by step

  1. 1Values used
  2. 2Network Error Budget
  3. 3Error Budget= 43.2 minutes
  4. 4Failed Requests Allowed= 500,000
  5. 5Budget Remaining= 21.2 minutes
  6. 6Burn Rate= 1.02 × budget pace
  7. 7Budget Status= Elevated burn — the budget will run out before the period ends

Assumptions and limits

  • The result is derived only from the 5 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax or fees or charges into account.
  • Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Network Error Budget calculated?

error budget = (1 − SLO) × period; allowed failures = (1 − SLO) × requests; burn rate = share of budget spent ÷ share of period elapsed. An SLO of 99.9% over 30 days is 43.2 minutes of allowed failure, and the same fraction applied to request volume gives the number of failed requests that fit inside the objective. The burn rate normalises consumption against elapsed time so that 1.0 is on-pace regardless of where you are in the period.

Why does Network Error Budget matter?

Error budgets convert reliability arguments into arithmetic: while budget remains you can ship changes, and when it is gone the answer to a risky change request is no.

What values do I need to enter?

This calculator takes 5 inputs: Service level objective, Budget period, Requests in the period, Budget consumed so far, Period elapsed. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

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