How is a correction insulin dose calculated?

Correction units = (current blood glucose − target) ÷ insulin sensitivity factor. The sensitivity factor (ISF) is how many mg/dL one unit of rapid-acting insulin is expected to lower glucose. Doses below the target are clamped to zero.

How do I estimate the insulin sensitivity factor?

A common estimate for rapid-acting analogues is the 1800 rule: ISF ≈ 1800 ÷ total daily insulin dose. For example, a patient on 60 units a day has an ISF of about 30 mg/dL per unit. Adjust to the individual response.

How is the IV insulin drip rate found?

Pump rate (mL/hr) = ordered units per hour ÷ bag concentration (units/mL). A standard mix of 100 units in 100 mL saline is 1 unit/mL, so an order of 4 units/hr runs at 4 mL/hr.

Are sliding scales recommended as sole therapy?

No. Using a correction sliding scale alone in hospital is discouraged because it treats hyperglycaemia reactively. Basal-bolus regimens that combine scheduled basal and prandial insulin with correction doses give better, safer control.

Why are doses below target shown as zero?

The correction formula gives a negative value when glucose is below the target, which would mean withholding insulin rather than giving a negative dose. The tool clamps these to zero so the scale only ever shows correction units to add.

Insulin Sliding Scale & Drip Rate Calculator

This tool builds a correction-dose insulin sliding scale from first principles and converts a continuous IV insulin order into a pump rate. Rather than printing a one-size-fits-all table, it uses the patient’s own target glucose and insulin sensitivity so the doses are individualised.

How it works

Each row of the scale uses the correction formula:

Correction units = (current BG − target BG) ÷ ISF

The insulin sensitivity factor (ISF) is the number of mg/dL that one unit of rapid-acting insulin is expected to lower the blood glucose. A widely used bedside estimate for rapid-acting analogues is the 1800 rule: ISF ≈ 1800 ÷ total daily dose. So a patient on 60 units/day has an ISF of roughly 30. When the current glucose is at or below target the formula gives zero or a negative number, which the tool clamps to 0 units — you never give a negative correction.

Converting the IV drip

For continuous IV insulin, the pump rate follows directly from the bag concentration:

Rate (mL/hr) = ordered units/hr ÷ concentration (units/mL)

The standard intensive-care mix of 100 units of regular insulin in 100 mL of saline is 1 unit/mL, so an order of 4 units/hr simply runs at 4 mL/hr.

Notes and safety

A correction scale is a planning aid, not a complete regimen. Sliding scales used alone are discouraged in hospital because they chase hyperglycaemia after it happens; basal-bolus dosing controls glucose far better. Always follow your institution’s protocol, double-check doses with a pharmacist, and monitor for hypoglycaemia. All calculation runs locally in your browser.