diff --git a/protocol-designer/src/components/StepEditForm/FlowRateField/FlowRateField.js b/protocol-designer/src/components/StepEditForm/FlowRateField/FlowRateField.js
index a412354f96d..c207fa2ac3d 100644
--- a/protocol-designer/src/components/StepEditForm/FlowRateField/FlowRateField.js
+++ b/protocol-designer/src/components/StepEditForm/FlowRateField/FlowRateField.js
@@ -1,5 +1,6 @@
 // @flow
 import * as React from 'react'
+import round from 'lodash/round'
 import {
   AlertModal,
   FormGroup,
@@ -121,7 +122,7 @@ export default class FlowRateField extends React.Component<Props, State> {
       minFlowRate > modalFlowRateNum ||
       modalFlowRateNum > maxFlowRate
     )
-    const correctDecimals = Number(modalFlowRateNum.toFixed(DECIMALS_ALLOWED)) === modalFlowRateNum
+    const correctDecimals = round(modalFlowRateNum, DECIMALS_ALLOWED) === modalFlowRateNum
     const allowSave = modalUseDefault || (!outOfBounds && correctDecimals)
 
     let errorMessage = null
diff --git a/protocol-designer/src/components/StepEditForm/TipPositionInput/TipPositionModal.js b/protocol-designer/src/components/StepEditForm/TipPositionInput/TipPositionModal.js
index aece40c7f2c..27351fb459e 100644
--- a/protocol-designer/src/components/StepEditForm/TipPositionInput/TipPositionModal.js
+++ b/protocol-designer/src/components/StepEditForm/TipPositionInput/TipPositionModal.js
@@ -2,6 +2,7 @@
 import * as React from 'react'
 import cx from 'classnames'
 import {connect} from 'react-redux'
+import round from 'lodash/round'
 import {
   Modal,
   OutlineButton,
@@ -25,6 +26,7 @@ import styles from './TipPositionInput.css'
 
 const SMALL_STEP_MM = 1
 const LARGE_STEP_MM = 10
+const DECIMALS_ALLOWED = 1
 
 type DP = { updateValue: (string) => mixed }
 
@@ -37,10 +39,10 @@ type OP = {
 }
 
 type Props = OP & DP
-type State = { value: string}
+type State = { value: string }
 
-const formatValue = (value: mixed) => (
-  parseFloat(value).toFixed(1)
+const formatValue = (value: number | string): string => (
+  String(round(Number(value), DECIMALS_ALLOWED))
 )
 
 class TipPositionModal extends React.Component<Props, State> {
@@ -75,14 +77,14 @@ class TipPositionModal extends React.Component<Props, State> {
   }
   handleChange = (e: SyntheticEvent<HTMLSelectElement>) => {
     const {value} = e.currentTarget
-    const valueFloat = formatValue(value)
+    const valueFloat = Number(formatValue(value))
     const maximumHeightMM = (this.props.wellHeightMM * 2)
 
     if (!value) {
       this.setState({value})
-    } else if (Number(valueFloat) > maximumHeightMM) {
+    } else if (valueFloat > maximumHeightMM) {
       this.setState({value: formatValue(maximumHeightMM)})
-    } else if (Number(valueFloat) >= 0) {
+    } else if (valueFloat >= 0) {
       const numericValue = value.replace(/[^.0-9]/, '')
       this.setState({value: numericValue.replace(/(\d*[.]{1}\d{1})(\d*)/, (match, group1) => group1)})
     } else {
diff --git a/protocol-designer/src/components/StepEditForm/TipPositionInput/TipPositionZAxisViz.js b/protocol-designer/src/components/StepEditForm/TipPositionInput/TipPositionZAxisViz.js
index a089156c6b8..5b8a5d6a30a 100644
--- a/protocol-designer/src/components/StepEditForm/TipPositionInput/TipPositionZAxisViz.js
+++ b/protocol-designer/src/components/StepEditForm/TipPositionInput/TipPositionZAxisViz.js
@@ -1,5 +1,6 @@
 // @flow
 import * as React from 'react'
+import round from 'lodash/round'
 
 import PIPETTE_TIP_IMAGE from '../../../images/pipette_tip.svg'
 import WELL_CROSS_SECTION_IMAGE from '../../../images/well_cross_section.svg'
@@ -7,6 +8,7 @@ import WELL_CROSS_SECTION_IMAGE from '../../../images/well_cross_section.svg'
 import styles from './TipPositionInput.css'
 
 const WELL_HEIGHT_PIXELS = 48
+const PIXEL_DECIMALS = 2
 type Props = {
   mmFromBottom: string,
   wellHeightMM: number,
@@ -15,7 +17,7 @@ type Props = {
 const TipPositionZAxisViz = (props: Props) => {
   const fractionOfWellHeight = Number(props.mmFromBottom) / props.wellHeightMM
   const pixelsFromBottom = (Number(fractionOfWellHeight) * WELL_HEIGHT_PIXELS) - WELL_HEIGHT_PIXELS
-  const roundedPixelsFromBottom = String(pixelsFromBottom.toFixed(2))
+  const roundedPixelsFromBottom = String(round(pixelsFromBottom, PIXEL_DECIMALS))
   const bottomPx = props.wellHeightMM ? roundedPixelsFromBottom : (parseFloat(props.mmFromBottom) - WELL_HEIGHT_PIXELS)
   return (
     <div className={styles.viz_wrapper}>
diff --git a/protocol-designer/src/components/steplist/utils.js b/protocol-designer/src/components/steplist/utils.js
index 3bad1c391a6..fab1b503ceb 100644
--- a/protocol-designer/src/components/steplist/utils.js
+++ b/protocol-designer/src/components/steplist/utils.js
@@ -12,6 +12,7 @@ export function formatVolume (inputVolume: ?string | ?number, sigDigits?: number
   return inputVolume || ''
 }
 
+const PERCENTAGE_DECIMALS_ALLOWED = 1
 export const formatPercentage = (part: number, total: number): string => {
-  return `${Number((part / total) * 100).toFixed(1)}%`
+  return `${round((part / total) * 100, PERCENTAGE_DECIMALS_ALLOWED)}%`
 }